diff --git a/NewLife.IoT/Drivers/DriverBase.cs b/NewLife.IoT/Drivers/DriverBase.cs
index 29a20a2..823ff28 100644
--- a/NewLife.IoT/Drivers/DriverBase.cs
+++ b/NewLife.IoT/Drivers/DriverBase.cs
@@ -26,7 +26,7 @@ public class DriverBase<TNode, TParameter> : DriverBase
     /// <param name="device">逻辑设备</param>
     /// <param name="parameter">参数。不同驱动的参数设置相差较大，对象字典具有较好灵活性，其对应IDriverParameter</param>
     /// <returns>节点对象，可存储站号等信息，仅驱动自己识别</returns>
-    public override INode Open(IDevice device, IDriverParameter parameter)
+    public override INode Open(IDevice device, IDriverParameter? parameter)
     {
         var node = new TNode
         {
@@ -55,7 +55,7 @@ public abstract class DriverBase : DisposeBase, IDriver, ILogFeature, ITracerFea
     /// </remarks>
     /// <param name="parameter">Xml/Json参数配置</param>
     /// <returns></returns>
-    public virtual IDriverParameter CreateParameter(String parameter)
+    public virtual IDriverParameter? CreateParameter(String? parameter)
     {
         var p = OnCreateParameter();
         if (p == null) return null;
@@ -76,7 +76,7 @@ public virtual IDriverParameter CreateParameter(String parameter)
 
     /// <summary>创建驱动参数对象，分析参数配置或创建默认参数</summary>
     /// <returns></returns>
-    protected virtual IDriverParameter OnCreateParameter() => null;
+    protected virtual IDriverParameter? OnCreateParameter() => null;
 
     /// <summary>获取产品物模型</summary>
     /// <remarks>
@@ -87,7 +87,7 @@ public virtual IDriverParameter CreateParameter(String parameter)
     /// 获取后，按新版本覆盖旧版本。
     /// </remarks>
     /// <returns></returns>
-    public virtual ThingSpec GetSpecification()
+    public virtual ThingSpec? GetSpecification()
     {
         var type = GetType();
         var spec = new ThingSpec
@@ -115,7 +115,7 @@ public virtual ThingSpec GetSpecification()
     /// <param name="device">逻辑设备</param>
     /// <param name="parameter">参数。不同驱动的参数设置相差较大，对象字典具有较好灵活性，其对应IDriverParameter</param>
     /// <returns>节点对象，可存储站号等信息，仅驱动自己识别</returns>
-    public virtual INode Open(IDevice device, IDriverParameter parameter)
+    public virtual INode Open(IDevice device, IDriverParameter? parameter)
     {
         var node = new Node
         {
@@ -140,7 +140,7 @@ public virtual void Close(INode node) { }
     /// <param name="node">节点对象，可存储站号等信息，仅驱动自己识别</param>
     /// <param name="points">点位集合</param>
     /// <returns></returns>
-    public virtual IDictionary<String, Object> Read(INode node, IPoint[] points) => throw new NotImplementedException();
+    public virtual IDictionary<String, Object?> Read(INode node, IPoint[] points) => throw new NotImplementedException();
 
     /// <summary>写入数据</summary>
     /// <remarks>
@@ -150,7 +150,7 @@ public virtual void Close(INode node) { }
     /// <param name="node">节点对象，可存储站号等信息，仅驱动自己识别</param>
     /// <param name="point">点位</param>
     /// <param name="value">数值</param>
-    public virtual Object Write(INode node, IPoint point, Object value) => throw new NotImplementedException();
+    public virtual Object? Write(INode node, IPoint point, Object? value) => throw new NotImplementedException();
 
     /// <summary>控制设备，特殊功能使用</summary>
     /// <remarks>
@@ -159,15 +159,15 @@ public virtual void Close(INode node) { }
     /// </remarks>
     /// <param name="node">节点对象，可存储站号等信息，仅驱动自己识别</param>
     /// <param name="parameters">参数</param>
-    public virtual Object Control(INode node, IDictionary<String, Object> parameters) => throw new NotImplementedException();
+    public virtual Object? Control(INode node, IDictionary<String, Object?> parameters) => throw new NotImplementedException();
     #endregion
 
     #region 日志
     /// <summary>日志</summary>
-    public ILog Log { get; set; }
+    public ILog Log { get; set; } = Logger.Null;
 
     /// <summary>性能追踪器</summary>
-    public ITracer Tracer { get; set; }
+    public ITracer? Tracer { get; set; }
 
     /// <summary>写日志</summary>
     /// <param name="format"></param>
diff --git a/NewLife.IoT/Drivers/DriverFactory.cs b/NewLife.IoT/Drivers/DriverFactory.cs
index f224d45..de572a5 100644
--- a/NewLife.IoT/Drivers/DriverFactory.cs
+++ b/NewLife.IoT/Drivers/DriverFactory.cs
@@ -2,7 +2,6 @@
 using System.Reflection;
 using NewLife.Log;
 using NewLife.Reflection;
-using NewLife.Xml;
 
 namespace NewLife.IoT.Drivers;
 
@@ -15,12 +14,12 @@ public class DriverFactory
     public static IDictionary<String, Type> Map => _map;
 
     /// <summary>驱动集合</summary>
-    public static IList<DriverInfo> Drivers { get; private set; }
+    public static IList<DriverInfo> Drivers { get; private set; } = null!;
 
     /// <summary>注册协议实现</summary>
     /// <param name="name"></param>
     /// <param name="type"></param>
-    public static void Register(String name, Type type)
+    public static void Register(String? name, Type type)
     {
         if (type == null) throw new ArgumentNullException(nameof(type));
         if (name.IsNullOrEmpty()) name = type.Name;
@@ -31,14 +30,14 @@ public static void Register(String name, Type type)
     /// <summary>注册协议实现</summary>
     /// <typeparam name="T"></typeparam>
     /// <param name="name"></param>
-    public static void Register<T>(String name = null) where T : IDriver => Register(name, typeof(T));
+    public static void Register<T>(String? name = null) where T : IDriver => Register(name, typeof(T));
 
-    private static readonly ConcurrentDictionary<String, IDriver> _cache = new();
+    private static readonly ConcurrentDictionary<String, IDriver?> _cache = new();
     /// <summary>创建协议实例，根据地址确保唯一，多设备共用同一个串口</summary>
     /// <param name="name">驱动名称。一般由DriverAttribute特性确定</param>
     /// <param name="identifier">唯一标识。没有传递标识时，每次返回新实例</param>
     /// <returns></returns>
-    public static IDriver Create(String name, String identifier)
+    public static IDriver? Create(String name, String identifier)
     {
         if (!_map.TryGetValue(name, out var type) || type == null) return null;
 
@@ -49,12 +48,12 @@ public static IDriver Create(String name, String identifier)
         return _cache.GetOrAdd(key, k => type.CreateInstance() as IDriver);
     }
 
-    private static readonly ConcurrentDictionary<String, IDriver> _defaults = new();
+    private static readonly ConcurrentDictionary<String, IDriver?> _defaults = new();
     /// <summary>创建驱动参数对象，分析参数配置或创建默认参数</summary>
     /// <param name="name">驱动名称。一般由DriverAttribute特性确定</param>
     /// <param name="parameter">Xml/Json参数配置</param>
     /// <returns></returns>
-    public static IDriverParameter CreateParameter(String name, String parameter)
+    public static IDriverParameter? CreateParameter(String name, String parameter)
     {
         if (!_map.TryGetValue(name, out var type) || type == null) return null;
 
diff --git a/NewLife.IoT/Drivers/DriverInfo.cs b/NewLife.IoT/Drivers/DriverInfo.cs
index 509ba4f..ad12739 100644
--- a/NewLife.IoT/Drivers/DriverInfo.cs
+++ b/NewLife.IoT/Drivers/DriverInfo.cs
@@ -1,6 +1,4 @@
-using System.Runtime.Serialization;
-using System.Xml.Serialization;
-using NewLife.IoT.ThingSpecification;
+using NewLife.IoT.ThingSpecification;
 
 namespace NewLife.IoT.Drivers;
 
@@ -9,31 +7,31 @@ public class DriverInfo
 {
     #region 属性
     /// <summary>名称</summary>
-    public String Name { get; set; }
+    public String Name { get; set; } = null!;
 
     /// <summary>显示名</summary>
-    public String DisplayName { get; set; }
+    public String? DisplayName { get; set; }
 
     /// <summary>类型。编程语言等，例如.NET</summary>
-    public String Type { get; set; }
+    public String? Type { get; set; }
 
     /// <summary>类型名</summary>
-    public String ClassName { get; set; }
+    public String? ClassName { get; set; }
 
     /// <summary>驱动版本</summary>
-    public String Version { get; set; }
+    public String? Version { get; set; }
 
     /// <summary>该驱动所依赖的IoT版本</summary>
-    public String IoTVersion { get; set; }
+    public String? IoTVersion { get; set; }
 
     /// <summary>描述</summary>
-    public String Description { get; set; }
+    public String? Description { get; set; }
 
     /// <summary>默认参数。可作为设备参数模版，Xml格式带注释</summary>
-    public String DefaultParameter { get; set; }
+    public String? DefaultParameter { get; set; }
 
     /// <summary>产品物模型。如果设备有固定点位属性、服务和事件，则直接返回，否则返回空</summary>
-    public ThingSpec Specification { get; set; }
+    public ThingSpec? Specification { get; set; }
     #endregion
 
     /// <summary>友好显示名称</summary>
diff --git a/NewLife.IoT/Drivers/IDriver.cs b/NewLife.IoT/Drivers/IDriver.cs
index 1eb5367..d0c5a0a 100644
--- a/NewLife.IoT/Drivers/IDriver.cs
+++ b/NewLife.IoT/Drivers/IDriver.cs
@@ -21,7 +21,7 @@ public interface IDriver
     /// </remarks>
     /// <param name="parameter">Xml/Json参数配置，为空时仅创建默认参数</param>
     /// <returns></returns>
-    IDriverParameter CreateParameter(String parameter = null);
+    IDriverParameter? CreateParameter(String? parameter = null);
 
     /// <summary>获取产品物模型</summary>
     /// <remarks>
@@ -32,7 +32,7 @@ public interface IDriver
     /// 获取后，按新版本覆盖旧版本。
     /// </remarks>
     /// <returns></returns>
-    ThingSpec GetSpecification();
+    ThingSpec? GetSpecification();
     #endregion
 
     #region 核心方法
@@ -42,7 +42,7 @@ public interface IDriver
     /// <param name="device">逻辑设备</param>
     /// <param name="parameter">参数。不同驱动的参数设置相差较大，对象字典具有较好灵活性，其对应IDriverParameter</param>
     /// <returns>节点对象，可存储站号等信息，仅驱动自己识别</returns>
-    INode Open(IDevice device, IDriverParameter parameter);
+    INode Open(IDevice device, IDriverParameter? parameter);
 
     /// <summary>
     /// 关闭设备节点。多节点共用通信链路时，需等最后一个节点关闭才能断开
@@ -58,7 +58,7 @@ public interface IDriver
     /// <param name="node">节点对象，可存储站号等信息，仅驱动自己识别</param>
     /// <param name="points">点位集合</param>
     /// <returns></returns>
-    IDictionary<String, Object> Read(INode node, IPoint[] points);
+    IDictionary<String, Object?> Read(INode node, IPoint[] points);
 
     /// <summary>写入数据</summary>
     /// <remarks>
@@ -68,7 +68,7 @@ public interface IDriver
     /// <param name="node">节点对象，可存储站号等信息，仅驱动自己识别</param>
     /// <param name="point">点位</param>
     /// <param name="value">数值</param>
-    Object Write(INode node, IPoint point, Object value);
+    Object? Write(INode node, IPoint point, Object? value);
 
     /// <summary>控制设备，特殊功能使用</summary>
     /// <remarks>
@@ -77,7 +77,7 @@ public interface IDriver
     /// </remarks>
     /// <param name="node">节点对象，可存储站号等信息，仅驱动自己识别</param>
     /// <param name="parameters">参数</param>
-    Object Control(INode node, IDictionary<String, Object> parameters);
+    Object? Control(INode node, IDictionary<String, Object?> parameters);
     #endregion
 }
 
@@ -94,6 +94,7 @@ public static class DriverExtensions
     public static INode Open(this IDriver driver, IDevice device, IDictionary<String, Object> parameters)
     {
         var type = driver.CreateParameter()?.GetType();
+        if (type == null) throw new InvalidOperationException();
 
         var ps = JsonHelper.Default.Convert(parameters, type) as IDriverParameter;
         var node = driver.Open(device, ps);
diff --git a/NewLife.IoT/Drivers/IDriverParameter.cs b/NewLife.IoT/Drivers/IDriverParameter.cs
index 599b5d4..abdd6bb 100644
--- a/NewLife.IoT/Drivers/IDriverParameter.cs
+++ b/NewLife.IoT/Drivers/IDriverParameter.cs
@@ -56,20 +56,20 @@ public static String GetKey(this IDriverParameter parameter)
     /// <summary>序列化参数对象为Xml</summary>
     /// <param name="parameter"></param>
     /// <returns></returns>
-    public static String EncodeParameter(this IDriverParameter parameter) => parameter?.ToXml(null, true).Trim((Char)0xFEFF);
+    public static String EncodeParameter(this IDriverParameter parameter) => parameter.ToXml(null, true).Trim((Char)0xFEFF);
 
     /// <summary>序列化参数字典为Xml</summary>
     /// <param name="parameter"></param>
     /// <returns></returns>
-    public static String EncodeParameter(this IDictionary<String, Object> parameter) => parameter?.ToXml(null, true).Trim((Char)0xFEFF);
+    public static String EncodeParameter(this IDictionary<String, Object> parameter) => parameter.ToXml(null, true).Trim((Char)0xFEFF);
 
     /// <summary>从Xml/Json反序列化为字典</summary>
     /// <param name="parameter"></param>
     /// <returns></returns>
-    public static IDictionary<String, Object> DecodeParameter(this String parameter)
+    public static IDictionary<String, Object?>? DecodeParameter(this String parameter)
     {
-        parameter = parameter?.Trim((Char)0xFEFF);
-        if (parameter.IsNullOrEmpty()) return null;
+        parameter = parameter.Trim((Char)0xFEFF);
+        if (parameter.IsNullOrEmpty()) throw new ArgumentNullException(nameof(parameter));
 
         // 按Xml或Json解析参数成为字典
         var ps = parameter.StartsWith("<") && parameter.EndsWith(">") ?
diff --git a/NewLife.IoT/Drivers/INode.cs b/NewLife.IoT/Drivers/INode.cs
index ff4711e..87c6df9 100644
--- a/NewLife.IoT/Drivers/INode.cs
+++ b/NewLife.IoT/Drivers/INode.cs
@@ -13,12 +13,12 @@ public interface INode
     /// <summary>
     /// 设备。业务逻辑设备
     /// </summary>
-    IDevice Device { get; set; }
+    IDevice? Device { get; set; }
 
     /// <summary>
     /// 参数。设备使用的专用参数
     /// </summary>
-    IDriverParameter Parameter { get; set; }
+    IDriverParameter? Parameter { get; set; }
 }
 
 /// <summary>
@@ -29,15 +29,15 @@ public class Node : INode
     /// <summary>
     /// 驱动。设备节点使用的驱动对象，可能多设备共用
     /// </summary>
-    public IDriver Driver { get; set; }
+    public IDriver Driver { get; set; } = null!;
 
     /// <summary>
     /// 设备。业务逻辑设备
     /// </summary>
-    public IDevice Device { get; set; }
+    public IDevice? Device { get; set; }
 
     /// <summary>
     /// 参数。设备使用的专用参数
     /// </summary>
-    public IDriverParameter Parameter { get; set; }
+    public IDriverParameter? Parameter { get; set; }
 }
\ No newline at end of file
diff --git a/NewLife.IoT/IDevice.cs b/NewLife.IoT/IDevice.cs
index 5b79028..0d3676b 100644
--- a/NewLife.IoT/IDevice.cs
+++ b/NewLife.IoT/IDevice.cs
@@ -15,13 +15,13 @@ public interface IDevice
     public String Code { get; set; }
 
     /// <summary>属性集合</summary>
-    IDictionary<String, Object> Properties { get; }
+    IDictionary<String, Object?> Properties { get; }
 
     /// <summary>产品物模型。自定义客户端或驱动插件内部，可借助物模型去规范所需要采集的数据</summary>
-    ThingSpec Specification { get; set; }
+    ThingSpec? Specification { get; set; }
 
     /// <summary>点位集合</summary>
-    IPoint[] Points { get; set; }
+    IPoint[]? Points { get; set; }
 
     /// <summary>服务集合</summary>
     IDictionary<String, Delegate> Services { get; }
@@ -60,7 +60,7 @@ public interface IDevice
     /// <summary>设置属性</summary>
     /// <param name="name"></param>
     /// <param name="value"></param>
-    void SetProperty(String name, Object value);
+    void SetProperty(String name, Object? value);
 
     /// <summary>添加自定义数据，批量上传</summary>
     /// <param name="name"></param>
diff --git a/NewLife.IoT/Models/DeviceInfo.cs b/NewLife.IoT/Models/DeviceInfo.cs
index c5a71aa..286170e 100644
--- a/NewLife.IoT/Models/DeviceInfo.cs
+++ b/NewLife.IoT/Models/DeviceInfo.cs
@@ -4,17 +4,17 @@
 public class DeviceInfo : IDeviceInfo
 {
     /// <summary>编码</summary>
-    public String Code { get; set; }
+    public String Code { get; set; } = null!;
 
     /// <summary>名称</summary>
-    public String Name { get; set; }
+    public String? Name { get; set; }
 
     /// <summary>产品编码</summary>
-    public String ProductCode { get; set; }
+    public String? ProductCode { get; set; }
 
     /// <summary>协议。选择使用哪一种驱动协议</summary>
-    public String Protocol { get; set; }
+    public String? Protocol { get; set; }
 
     /// <summary>设备参数。Xml/Json格式配置，根据协议驱动来解析</summary>
-    public String Parameter { get; set; }
+    public String? Parameter { get; set; }
 }
\ No newline at end of file
diff --git a/NewLife.IoT/Models/DeviceModel.cs b/NewLife.IoT/Models/DeviceModel.cs
index eb8568f..aaa1566 100644
--- a/NewLife.IoT/Models/DeviceModel.cs
+++ b/NewLife.IoT/Models/DeviceModel.cs
@@ -4,13 +4,13 @@
 public class DeviceModel : IDeviceInfo
 {
     /// <summary>编码</summary>
-    public String Code { get; set; }
+    public String Code { get; set; } = null!;
 
     /// <summary>名称</summary>
-    public String Name { get; set; }
+    public String? Name { get; set; }
 
     /// <summary>产品编码</summary>
-    public String ProductCode { get; set; }
+    public String? ProductCode { get; set; }
 
     /// <summary>上报间隔。属性上报间隔，采集后暂存数据，定时上报，默认60秒，-1表示不上报属性</summary>
     public Int32 PostPeriod { get; set; }
@@ -22,10 +22,10 @@ public class DeviceModel : IDeviceInfo
     public Int32 PollingTime { get; set; }
 
     /// <summary>协议。选择使用哪一种驱动协议</summary>
-    public String Protocol { get; set; }
+    public String? Protocol { get; set; }
 
     /// <summary>设备参数。Xml/Json格式配置，根据协议驱动来解析</summary>
-    public String Parameter { get; set; }
+    public String? Parameter { get; set; }
 
     /// <summary>更新时间。用于判断数据变化</summary>
     public DateTime UpdateTime { get; set; }
diff --git a/NewLife.IoT/Models/IDeviceInfo.cs b/NewLife.IoT/Models/IDeviceInfo.cs
index 1ef0440..b7041be 100644
--- a/NewLife.IoT/Models/IDeviceInfo.cs
+++ b/NewLife.IoT/Models/IDeviceInfo.cs
@@ -13,8 +13,8 @@ public interface IDeviceInfo
     String Code { get; set; }
 
     /// <summary>名称</summary>
-    String Name { get; set; }
+    String? Name { get; set; }
 
     /// <summary>产品编码</summary>
-    String ProductCode { get; set; }
+    String? ProductCode { get; set; }
 }
\ No newline at end of file
diff --git a/NewLife.IoT/Models/ServiceRequest.cs b/NewLife.IoT/Models/ServiceRequest.cs
index 6244441..259aa93 100644
--- a/NewLife.IoT/Models/ServiceRequest.cs
+++ b/NewLife.IoT/Models/ServiceRequest.cs
@@ -7,13 +7,13 @@ public class ServiceRequest
     public Int32 DeviceId { get; set; }
 
     /// <summary>设备编码。目标设备或其子设备</summary>
-    public String DeviceCode { get; set; }
+    public String? DeviceCode { get; set; }
 
     /// <summary>服务名</summary>
-    public String ServiceName { get; set; }
+    public String ServiceName { get; set; } = null!;
 
     /// <summary>入参。传递给该服务的参数，常见Json格式</summary>
-    public String InputData { get; set; }
+    public String? InputData { get; set; }
 
     /// <summary>开始执行时间。用于提前下发指令后延期执行</summary>
     public DateTime StartTime { get;set; }
diff --git a/NewLife.IoT/NewLife.IoT.csproj b/NewLife.IoT/NewLife.IoT.csproj
index 37a7419..9d16a12 100644
--- a/NewLife.IoT/NewLife.IoT.csproj
+++ b/NewLife.IoT/NewLife.IoT.csproj
@@ -13,6 +13,7 @@
     <Deterministic>false</Deterministic>
     <OutputPath>..\Bin</OutputPath>
     <GenerateDocumentationFile>True</GenerateDocumentationFile>
+    <Nullable>enable</Nullable>
     <ImplicitUsings>enable</ImplicitUsings>
     <LangVersion>latest</LangVersion>
     <SignAssembly>True</SignAssembly>
@@ -27,7 +28,7 @@
     <RepositoryUrl>https://github.com/NewLifeX/NewLife.IoT</RepositoryUrl>
     <RepositoryType>git</RepositoryType>
     <PackageTags>物联网;IoT;边缘计算;Edge;新生命团队;NewLife;$(AssemblyName)</PackageTags>
-    <PackageReleaseNotes>增强IDriver.Open；恢复支持net45</PackageReleaseNotes>
+    <PackageReleaseNotes>启用可空特性</PackageReleaseNotes>
     <PackageLicenseExpression>MIT</PackageLicenseExpression>
     <PublishRepositoryUrl>true</PublishRepositoryUrl>
     <EmbedUntrackedSources>true</EmbedUntrackedSources>
@@ -49,10 +50,10 @@
     </PackageReference>
   </ItemGroup>
   <ItemGroup Condition="'$(TargetFramework)'!='net40'">
-    <PackageReference Include="NewLife.Core" Version="10.5.2023.801" />
+    <PackageReference Include="NewLife.Core" Version="10.6.2023.1001" />
   </ItemGroup>
   <ItemGroup Condition="'$(TargetFramework)'=='net40'">
-    <PackageReference Include="NewLife.Core" Version="10.5.2023.801-net40" />
+    <PackageReference Include="NewLife.Core" Version="10.6.2023.1001-net40" />
   </ItemGroup>
 
   <ItemGroup>
diff --git a/NewLife.IoT/ThingModels/DataModel.cs b/NewLife.IoT/ThingModels/DataModel.cs
index 57a4c86..a3fe764 100644
--- a/NewLife.IoT/ThingModels/DataModel.cs
+++ b/NewLife.IoT/ThingModels/DataModel.cs
@@ -7,8 +7,8 @@ public class DataModel
     public Int64 Time { get; set; }
 
     /// <summary>名称</summary>
-    public String Name { get; set; }
+    public String Name { get; set; } = null!;
 
     /// <summary>数据</summary>
-    public String Value { get; set; }
+    public String? Value { get; set; }
 }
\ No newline at end of file
diff --git a/NewLife.IoT/ThingModels/DataModels.cs b/NewLife.IoT/ThingModels/DataModels.cs
index f73574f..f95fbbc 100644
--- a/NewLife.IoT/ThingModels/DataModels.cs
+++ b/NewLife.IoT/ThingModels/DataModels.cs
@@ -4,8 +4,8 @@
 public class DataModels
 {
     /// <summary>设备编码</summary>
-    public String DeviceCode { get; set; }
+    public String DeviceCode { get; set; } = null!;
 
     /// <summary>数据集合</summary>
-    public DataModel[] Items { get; set; }
+    public DataModel[]? Items { get; set; }
 }
\ No newline at end of file
diff --git a/NewLife.IoT/ThingModels/DevicePropertyModel.cs b/NewLife.IoT/ThingModels/DevicePropertyModel.cs
index 9b5cd85..3686058 100644
--- a/NewLife.IoT/ThingModels/DevicePropertyModel.cs
+++ b/NewLife.IoT/ThingModels/DevicePropertyModel.cs
@@ -4,5 +4,5 @@
 public class DevicePropertyModel : PropertyModel
 {
     /// <summary>设备编码</summary>
-    public String DeviceCode { get; set; }
+    public String DeviceCode { get; set; } = null!;
 }
diff --git a/NewLife.IoT/ThingModels/EventModel.cs b/NewLife.IoT/ThingModels/EventModel.cs
index 7d3b97e..cb8b77c 100644
--- a/NewLife.IoT/ThingModels/EventModel.cs
+++ b/NewLife.IoT/ThingModels/EventModel.cs
@@ -7,11 +7,11 @@ public class EventModel
     public Int64 Time { get; set; }
 
     /// <summary>事件类型。info/alert/error</summary>
-    public String Type { get; set; }
+    public String? Type { get; set; }
 
     /// <summary>名称。事件名称，例如LightOpen</summary>
-    public String Name { get; set; }
+    public String? Name { get; set; }
 
     /// <summary>内容。事件详情</summary>
-    public String Remark { get; set; }
+    public String? Remark { get; set; }
 }
\ No newline at end of file
diff --git a/NewLife.IoT/ThingModels/EventModels.cs b/NewLife.IoT/ThingModels/EventModels.cs
index 64edf38..deb7506 100644
--- a/NewLife.IoT/ThingModels/EventModels.cs
+++ b/NewLife.IoT/ThingModels/EventModels.cs
@@ -4,8 +4,8 @@
 public class EventModels
 {
     /// <summary>设备编码</summary>
-    public String DeviceCode { get; set; }
+    public String DeviceCode { get; set; } = null!;
 
     /// <summary>事件集合</summary>
-    public EventModel[] Items { get; set; }
+    public EventModel[]? Items { get; set; }
 }
\ No newline at end of file
diff --git a/NewLife.IoT/ThingModels/IPoint.cs b/NewLife.IoT/ThingModels/IPoint.cs
index 66324f6..7975594 100644
--- a/NewLife.IoT/ThingModels/IPoint.cs
+++ b/NewLife.IoT/ThingModels/IPoint.cs
@@ -7,14 +7,14 @@ namespace NewLife.IoT.ThingModels;
 public interface IPoint
 {
     /// <summary>名称</summary>
-    String Name { get; set; }
+    String? Name { get; set; }
 
     /// <summary>地址。表示点位的地址，具体含义由设备驱动决定。例如常规地址6，字母地址DI07，Modbus地址4x0015，位域地址D012.05，比特位置0~15</summary>
     /// <remarks>在某些场景中，特殊点位地址（如#）表示虚拟地址，该点位数值由ReadRule表达式动态计算得到，点位信息并不会传递给驱动层</remarks>
-    String Address { get; set; }
+    String? Address { get; set; }
 
     /// <summary>数据类型。来自物模型</summary>
-    String Type { get; set; }
+    String? Type { get; set; }
 
     /// <summary>大小。数据字节数，或字符串长度，Modbus寄存器一般占2个字节</summary>
     Int32 Length { get; set; }
@@ -46,7 +46,7 @@ public static Object Convert(this IPoint point, Byte[] data)
             TypeCode.UInt16 => BitConverter.ToUInt16(data, 0),
             TypeCode.UInt32 => BitConverter.ToUInt32(data, 0),
             TypeCode.UInt64 => BitConverter.ToUInt64(data, 0),
-            _ => null,
+            _ => throw new NotSupportedException(),
         };
     }
 
@@ -56,24 +56,24 @@ public static Object Convert(this IPoint point, Byte[] data)
     /// <param name="point">点位</param>
     /// <param name="value">数据对象</param>
     /// <returns></returns>
-    public static Byte[] GetBytes(this IPoint point, Object value)
+    public static Byte[]? GetBytes(this IPoint point, Object value)
     {
         var type = point.GetNetType();
         var val = value.ChangeType(type);
 
         return type.GetTypeCode() switch
         {
-            TypeCode.Boolean => BitConverter.GetBytes((Boolean)val),
-            TypeCode.Byte => new[] { (Byte)val },
-            TypeCode.Char => BitConverter.GetBytes((Char)val),
-            TypeCode.Double => BitConverter.GetBytes((Double)val),
-            TypeCode.Int16 => BitConverter.GetBytes((Int16)val),
-            TypeCode.Int32 => BitConverter.GetBytes((Int32)val),
-            TypeCode.Int64 => BitConverter.GetBytes((Int64)val),
-            TypeCode.Single => BitConverter.GetBytes((Single)val),
-            TypeCode.UInt16 => BitConverter.GetBytes((UInt16)val),
-            TypeCode.UInt32 => BitConverter.GetBytes((UInt32)val),
-            TypeCode.UInt64 => BitConverter.GetBytes((UInt64)val),
+            TypeCode.Boolean => BitConverter.GetBytes((Boolean)(val ?? false)),
+            TypeCode.Byte => new[] { (Byte)(val ?? 0) },
+            TypeCode.Char => BitConverter.GetBytes((Char)(val ?? 0)),
+            TypeCode.Double => BitConverter.GetBytes((Double)(val ?? 0)),
+            TypeCode.Int16 => BitConverter.GetBytes((Int16)(val ?? 0)),
+            TypeCode.Int32 => BitConverter.GetBytes((Int32)(val ?? 0)),
+            TypeCode.Int64 => BitConverter.GetBytes((Int64)(val ?? 0)),
+            TypeCode.Single => BitConverter.GetBytes((Single)(val ?? 0)),
+            TypeCode.UInt16 => BitConverter.GetBytes((UInt16)(val ?? 0)),
+            TypeCode.UInt32 => BitConverter.GetBytes((UInt32)(val ?? 0)),
+            TypeCode.UInt64 => BitConverter.GetBytes((UInt64)(val ?? 0)),
             _ => null,
         };
     }
@@ -84,7 +84,7 @@ public static Byte[] GetBytes(this IPoint point, Object value)
     /// <param name="data">原始数据，一般是字符串</param>
     /// <param name="spec">物模型</param>
     /// <returns></returns>
-    public static UInt16[] ConvertToBit(this IPoint point, Object data, ThingSpec spec = null)
+    public static UInt16[]? ConvertToBit(this IPoint point, Object data, ThingSpec? spec = null)
     {
         var type = TypeHelper.GetNetType(point);
         if (type == null)
@@ -120,7 +120,7 @@ public static UInt16[] ConvertToBit(this IPoint point, Object data, ThingSpec sp
     /// <param name="data">原始数据，一般是字符串</param>
     /// <param name="spec">物模型</param>
     /// <returns>返回短整型数组，有可能一个整数拆分为双字</returns>
-    public static UInt16[] ConvertToWord(this IPoint point, Object data, ThingSpec spec = null)
+    public static UInt16[]? ConvertToWord(this IPoint point, Object data, ThingSpec? spec = null)
     {
         var type = TypeHelper.GetNetType(point);
         if (type == null)
diff --git a/NewLife.IoT/ThingModels/PointModel.cs b/NewLife.IoT/ThingModels/PointModel.cs
index 74eff07..5605b71 100644
--- a/NewLife.IoT/ThingModels/PointModel.cs
+++ b/NewLife.IoT/ThingModels/PointModel.cs
@@ -4,23 +4,23 @@
 public class PointModel : IPoint
 {
     /// <summary>名称</summary>
-    public String Name { get; set; }
+    public String? Name { get; set; }
 
     /// <summary>地址。表示点位的地址，具体含义由设备驱动决定。例如常规地址6，字母地址DI07，Modbus地址4x0015，位域地址D012.05，比特位置0~15</summary>
     /// <remarks>在某些场景中，特殊点位地址（如#）表示虚拟地址，该点位数值由ReadRule表达式动态计算得到，点位信息并不会传递给驱动层</remarks>
-    public String Address { get; set; }
+    public String? Address { get; set; }
 
     /// <summary>数据类型。来自物模型</summary>
-    public String Type { get; set; }
+    public String? Type { get; set; }
 
     /// <summary>大小。数据字节数，或字符串长度，Modbus寄存器一般占2个字节</summary>
     public Int32 Length { get; set; }
 
     /// <summary>读取规则。数据解析规则，表达式或脚本</summary>
-    public String ReadRule { get; set; }
+    public String? ReadRule { get; set; }
 
     /// <summary>写入规则。数据反解析规则，表达式或脚本</summary>
-    public String WriteRule { get; set; }
+    public String? WriteRule { get; set; }
 
     /// <summary>已重载。友好显示</summary>
     /// <returns></returns>
diff --git a/NewLife.IoT/ThingModels/PropertyModel.cs b/NewLife.IoT/ThingModels/PropertyModel.cs
index cf61ef0..5f6230d 100644
--- a/NewLife.IoT/ThingModels/PropertyModel.cs
+++ b/NewLife.IoT/ThingModels/PropertyModel.cs
@@ -4,8 +4,8 @@
 public class PropertyModel
 {
     /// <summary>名称</summary>
-    public String Name { get; set; }
+    public String Name { get; set; } = null!;
 
     /// <summary>数值</summary>
-    public Object Value { get; set; }
+    public Object? Value { get; set; }
 }
\ No newline at end of file
diff --git a/NewLife.IoT/ThingModels/PropertyModels.cs b/NewLife.IoT/ThingModels/PropertyModels.cs
index a2c231a..dbe265a 100644
--- a/NewLife.IoT/ThingModels/PropertyModels.cs
+++ b/NewLife.IoT/ThingModels/PropertyModels.cs
@@ -6,8 +6,8 @@
 public class PropertyModels
 {
     /// <summary>设备编码</summary>
-    public String DeviceCode { get; set; }
+    public String DeviceCode { get; set; } = null!;
 
     /// <summary>属性集合</summary>
-    public PropertyModel[] Items { get; set; }
+    public PropertyModel[]? Items { get; set; }
 }
\ No newline at end of file
diff --git a/NewLife.IoT/ThingModels/ServiceEventArgs.cs b/NewLife.IoT/ThingModels/ServiceEventArgs.cs
index d2fe1fb..10f5489 100644
--- a/NewLife.IoT/ThingModels/ServiceEventArgs.cs
+++ b/NewLife.IoT/ThingModels/ServiceEventArgs.cs
@@ -8,10 +8,10 @@ public class ServiceEventArgs : EventArgs
     /// <summary>
     /// 命令
     /// </summary>
-    public ServiceModel Model { get; set; }
+    public ServiceModel? Model { get; set; }
 
     /// <summary>
     /// 响应
     /// </summary>
-    public ServiceReplyModel Reply { get; set; }
+    public ServiceReplyModel? Reply { get; set; }
 }
\ No newline at end of file
diff --git a/NewLife.IoT/ThingModels/ServiceModel.cs b/NewLife.IoT/ThingModels/ServiceModel.cs
index bb4276e..eac4213 100644
--- a/NewLife.IoT/ThingModels/ServiceModel.cs
+++ b/NewLife.IoT/ThingModels/ServiceModel.cs
@@ -7,10 +7,10 @@ public class ServiceModel
     public Int64 Id { get; set; }
 
     /// <summary>服务名。如SetProperty</summary>
-    public String Name { get; set; }
+    public String Name { get; set; } = null!;
 
     /// <summary>入参。传递给该服务的参数，常见Json格式</summary>
-    public String InputData { get; set; }
+    public String? InputData { get; set; }
 
     /// <summary>开始执行时间。用于提前下发指令后延期执行，暂时不支持取消</summary>
     public DateTime StartTime { get; set; }
@@ -19,8 +19,8 @@ public class ServiceModel
     public DateTime Expire { get; set; }
 
     /// <summary>设备编码。服务调用请求发送给网关设备时，该参数指定子设备编码</summary>
-    public String DeviceCode { get; set; }
+    public String? DeviceCode { get; set; }
 
     /// <summary>链路追踪</summary>
-    public String TraceId { get; set; }
+    public String? TraceId { get; set; }
 }
\ No newline at end of file
diff --git a/NewLife.IoT/ThingModels/ServiceReplyModel.cs b/NewLife.IoT/ThingModels/ServiceReplyModel.cs
index f59a8ba..57290ec 100644
--- a/NewLife.IoT/ThingModels/ServiceReplyModel.cs
+++ b/NewLife.IoT/ThingModels/ServiceReplyModel.cs
@@ -10,5 +10,5 @@ public class ServiceReplyModel
     public ServiceStatus Status { get; set; }
 
     /// <summary>返回数据</summary>
-    public String Data { get; set; }
+    public String? Data { get; set; }
 }
\ No newline at end of file
diff --git a/NewLife.IoT/ThingModels/ShadowModel.cs b/NewLife.IoT/ThingModels/ShadowModel.cs
index 6054a49..3002e51 100644
--- a/NewLife.IoT/ThingModels/ShadowModel.cs
+++ b/NewLife.IoT/ThingModels/ShadowModel.cs
@@ -6,8 +6,8 @@
 public class ShadowModel
 {
     /// <summary>设备编码</summary>
-    public String DeviceCode { get; set; }
+    public String DeviceCode { get; set; } = null!;
 
     /// <summary>影子</summary>
-    public Object Shadow { get; set; }
+    public Object? Shadow { get; set; }
 }
\ No newline at end of file
diff --git a/NewLife.IoT/ThingSpecification/DataSpecs.cs b/NewLife.IoT/ThingSpecification/DataSpecs.cs
index 38079b3..538b2a9 100644
--- a/NewLife.IoT/ThingSpecification/DataSpecs.cs
+++ b/NewLife.IoT/ThingSpecification/DataSpecs.cs
@@ -13,10 +13,10 @@ public class DataSpecs
     public Double Max { get; set; }
 
     /// <summary>单位</summary>
-    public String Unit { get; set; }
+    public String? Unit { get; set; }
 
     /// <summary>单位名称</summary>
-    public String UnitName { get; set; }
+    public String? UnitName { get; set; }
 
     /// <summary>步进</summary>
     public Double Step { get; set; }
@@ -25,16 +25,16 @@ public class DataSpecs
     public Int32 Length { get; set; }
 
     /// <summary>枚举映射。布尔型和数字型特有，例如“0=关,1=开”，又如“1=东,2=南,3=西,4=北”</summary>
-    public IDictionary<String, String> Mapping { get; set; }
+    public IDictionary<String, String>? Mapping { get; set; }
     #endregion
 
     #region 方法
     /// <summary>根据指定数据类型获取成员字典，不同类型所需要的字段不一样</summary>
     /// <param name="type">数据类型</param>
     /// <returns></returns>
-    public IDictionary<String, Object> GetDictionary(String type)
+    public IDictionary<String, Object?> GetDictionary(String type)
     {
-        var ds = new Dictionary<String, Object>();
+        var ds = new Dictionary<String, Object?>();
 
         var t = TypeHelper.GetNetType(type);
         if (t == null) return this.ToDictionary();
diff --git a/NewLife.IoT/ThingSpecification/EventSpec.cs b/NewLife.IoT/ThingSpecification/EventSpec.cs
index f955ebc..070efae 100644
--- a/NewLife.IoT/ThingSpecification/EventSpec.cs
+++ b/NewLife.IoT/ThingSpecification/EventSpec.cs
@@ -14,22 +14,22 @@ public class EventSpec : SpecBase
     /// <summary>
     /// 类型。info/warning/error
     /// </summary>
-    public String Type { get; set; }
+    public String? Type { get; set; }
 
     /// <summary>
     /// 描述
     /// </summary>
     [DataMember(Name="desc")]
-    public String Description { get; set; }
+    public String? Description { get; set; }
 
     /// <summary>
     /// 方法
     /// </summary>
-    public String Method { get; set; }
+    public String? Method { get; set; }
 
     /// <summary>
     /// 输出
     /// </summary>
-    public PropertySpec[] OutputData { get; set; }
+    public PropertySpec[]? OutputData { get; set; }
     #endregion
 }
\ No newline at end of file
diff --git a/NewLife.IoT/ThingSpecification/Profile.cs b/NewLife.IoT/ThingSpecification/Profile.cs
index 5ca70f3..4d0347f 100644
--- a/NewLife.IoT/ThingSpecification/Profile.cs
+++ b/NewLife.IoT/ThingSpecification/Profile.cs
@@ -13,5 +13,5 @@ public class Profile
     /// <summary>
     /// 产品编码
     /// </summary>
-    public String ProductKey { get; set; }
+    public String? ProductKey { get; set; }
 }
\ No newline at end of file
diff --git a/NewLife.IoT/ThingSpecification/PropertyExtend.cs b/NewLife.IoT/ThingSpecification/PropertyExtend.cs
index 0b93e9a..e502bae 100644
--- a/NewLife.IoT/ThingSpecification/PropertyExtend.cs
+++ b/NewLife.IoT/ThingSpecification/PropertyExtend.cs
@@ -13,10 +13,10 @@ public class PropertyExtend : IDictionarySource
     #region 属性
     /// <summary>唯一标识</summary>
     [DataMember(Name = "identifier")]
-    public String Id { get; set; }
+    public String Id { get; set; } = null!;
 
     /// <summary>采集点位置信息。常规地址6，Modbus地址 4x0023，位域地址D12.05，虚拟点位地址#</summary>
-    public String Address { get; set; }
+    public String? Address { get; set; }
 
     /// <summary>交换16。字节交换，12转21，默认false大端</summary>
     public Boolean Swap16 { get; set; }
@@ -31,10 +31,10 @@ public class PropertyExtend : IDictionarySource
     public Single Constant { get; set; }
 
     /// <summary>读取规则。数据解析规则，表达式或脚本</summary>
-    public String ReadRule { get; set; }
+    public String? ReadRule { get; set; }
 
     /// <summary>写入规则。数据反解析规则，表达式或脚本</summary>
-    public String WriteRule { get; set; }
+    public String? WriteRule { get; set; }
 
     /// <summary>事件模式。在客户端或服务端生成属性变更事件</summary>
     public EventModes EventMode { get; set; }
diff --git a/NewLife.IoT/ThingSpecification/PropertySpec.cs b/NewLife.IoT/ThingSpecification/PropertySpec.cs
index 7dbd63d..a71d5e5 100644
--- a/NewLife.IoT/ThingSpecification/PropertySpec.cs
+++ b/NewLife.IoT/ThingSpecification/PropertySpec.cs
@@ -15,12 +15,12 @@ public class PropertySpec : SpecBase, IDictionarySource
     /// <summary>
     /// 访问模式
     /// </summary>
-    public String AccessMode { get; set; }
+    public String? AccessMode { get; set; }
 
     /// <summary>
     /// 数据类型
     /// </summary>
-    public TypeSpec DataType { get; set; }
+    public TypeSpec? DataType { get; set; }
 
     ///// <summary>
     ///// 采集点位置信息
@@ -60,7 +60,7 @@ public static PropertySpec Create(String id, String name, String type, Int32 len
     /// <returns></returns>
     public static PropertySpec Create(MemberInfo member, Int32 length = 0)
     {
-        if (member == null) return null;
+        //if (member == null) return null;
 
         var ps = new PropertySpec
         {
@@ -83,9 +83,9 @@ public static PropertySpec Create(MemberInfo member, Int32 length = 0)
     #region 方法
     /// <summary>转字典。根据不同类型，提供不一样的序列化能力</summary>
     /// <returns></returns>
-    public IDictionary<String, Object> ToDictionary()
+    public IDictionary<String, Object?> ToDictionary()
     {
-        var dic = new Dictionary<String, Object>();
+        var dic = new Dictionary<String, Object?>();
         if (!Id.IsNullOrEmpty())
             dic.Add("identifier", Id);
         if (!Name.IsNullOrEmpty())
diff --git a/NewLife.IoT/ThingSpecification/ServiceSpec.cs b/NewLife.IoT/ThingSpecification/ServiceSpec.cs
index dce1ecd..5386a0b 100644
--- a/NewLife.IoT/ThingSpecification/ServiceSpec.cs
+++ b/NewLife.IoT/ThingSpecification/ServiceSpec.cs
@@ -16,28 +16,28 @@ public class ServiceSpec : SpecBase
     /// 调用类型。sync/async
     /// </summary>
     [DataMember(Name = "callType")]
-    public String Type { get; set; }
+    public String? Type { get; set; }
 
     /// <summary>
     /// 描述
     /// </summary>
     [DataMember(Name = "desc")]
-    public String Description { get; set; }
+    public String? Description { get; set; }
 
     /// <summary>
     /// 方法
     /// </summary>
-    public String Method { get; set; }
+    public String? Method { get; set; }
 
     /// <summary>
     /// 输入
     /// </summary>
-    public PropertySpec[] InputData { get; set; }
+    public PropertySpec[]? InputData { get; set; }
 
     /// <summary>
     /// 输出
     /// </summary>
-    public PropertySpec[] OutputData { get; set; }
+    public PropertySpec[]? OutputData { get; set; }
     #endregion
 
     #region 方法
@@ -51,7 +51,7 @@ public class ServiceSpec : SpecBase
     /// <returns></returns>
     public static ServiceSpec Create(MethodBase method)
     {
-        if (method == null) return null;
+        //if (method == null) return null;
 
         var ss = new ServiceSpec
         {
@@ -79,7 +79,7 @@ public static ServiceSpec Create(MethodBase method)
     /// <returns></returns>
     public static PropertySpec Create(ParameterInfo member)
     {
-        if (member == null) return null;
+        //if (member == null) return null;
 
         var ps = new PropertySpec
         {
diff --git a/NewLife.IoT/ThingSpecification/SpecBase.cs b/NewLife.IoT/ThingSpecification/SpecBase.cs
index 9a4bd29..9832354 100644
--- a/NewLife.IoT/ThingSpecification/SpecBase.cs
+++ b/NewLife.IoT/ThingSpecification/SpecBase.cs
@@ -12,12 +12,12 @@ public abstract class SpecBase
     /// 唯一标识
     /// </summary>
     [DataMember(Name = "identifier")]
-    public String Id { get; set; }
+    public String Id { get; set; } = null!;
 
     /// <summary>
     /// 名称
     /// </summary>
-    public String Name { get; set; }
+    public String? Name { get; set; }
 
     /// <summary>
     /// 是否必须
diff --git a/NewLife.IoT/ThingSpecification/ThingSpec.cs b/NewLife.IoT/ThingSpecification/ThingSpec.cs
index 9d70e00..6ed5dbd 100644
--- a/NewLife.IoT/ThingSpecification/ThingSpec.cs
+++ b/NewLife.IoT/ThingSpecification/ThingSpec.cs
@@ -13,19 +13,19 @@ public class ThingSpec
     public String Schema { get; set; } = "http://iot.feifan.link/schema.json";
 
     /// <summary>简介</summary>
-    public Profile Profile { get; set; }
+    public Profile? Profile { get; set; }
 
     /// <summary>属性</summary>
-    public PropertySpec[] Properties { get; set; }
+    public PropertySpec[]? Properties { get; set; }
 
     /// <summary>事件</summary>
-    public EventSpec[] Events { get; set; }
+    public EventSpec[]? Events { get; set; }
 
     /// <summary>服务</summary>
-    public ServiceSpec[] Services { get; set; }
+    public ServiceSpec[]? Services { get; set; }
 
     /// <summary>属性扩展</summary>
-    public PropertyExtend[] ExtendedProperties { get; set; }
+    public PropertyExtend[]? ExtendedProperties { get; set; }
     #endregion
 
     #region 方法
@@ -36,7 +36,7 @@ public class ThingSpec
     /// <param name="length">长度</param>
     /// <param name="address">点位地址</param>
     /// <returns></returns>
-    public void AddProperty(String id, String name, String type, Int32 length = 0, String address = null)
+    public void AddProperty(String id, String name, String type, Int32 length = 0, String? address = null)
     {
         {
             var ps = PropertySpec.Create(id, name, type, length);
diff --git a/NewLife.IoT/ThingSpecification/TypeSpec.cs b/NewLife.IoT/ThingSpecification/TypeSpec.cs
index 6ab4f14..2b9e279 100644
--- a/NewLife.IoT/ThingSpecification/TypeSpec.cs
+++ b/NewLife.IoT/ThingSpecification/TypeSpec.cs
@@ -10,12 +10,12 @@ public class TypeSpec : IDictionarySource
     /// <summary>
     /// 类型。int/float/text
     /// </summary>
-    public String Type { get; set; }
+    public String? Type { get; set; }
 
     /// <summary>
     /// 数据规范
     /// </summary>
-    public DataSpecs Specs { get; set; }
+    public DataSpecs? Specs { get; set; }
 
     /// <summary>转字典。根据不同类型，提供不一样的序列化能力</summary>
     /// <returns></returns>
diff --git a/NewLife.IoT/TypeHelper.cs b/NewLife.IoT/TypeHelper.cs
index e749d94..d630d87 100644
--- a/NewLife.IoT/TypeHelper.cs
+++ b/NewLife.IoT/TypeHelper.cs
@@ -64,7 +64,7 @@ public static Int32 GetLength(Type type)
     /// <param name="type"></param>
     /// <returns></returns>
     /// <exception cref="NotImplementedException"></exception>
-    public static Type GetNetType(String type)
+    public static Type? GetNetType(String? type)
     {
         if (type.IsNullOrEmpty()) return null;
 
diff --git a/XUnitTest/XUnitTest.csproj b/XUnitTest/XUnitTest.csproj
index ca766f4..5244618 100644
--- a/XUnitTest/XUnitTest.csproj
+++ b/XUnitTest/XUnitTest.csproj
@@ -13,10 +13,10 @@
 
   <ItemGroup>
     <PackageReference Include="Microsoft.Extensions.DependencyInjection" Version="7.0.0" />
-    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.7.1" />
+    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.7.2" />
     <PackageReference Include="NewLife.PC" Version="1.0.2023.511" />
-    <PackageReference Include="xunit" Version="2.5.0" />
-    <PackageReference Include="xunit.runner.visualstudio" Version="2.5.0">
+    <PackageReference Include="xunit" Version="2.5.1" />
+    <PackageReference Include="xunit.runner.visualstudio" Version="2.5.1">
       <PrivateAssets>all</PrivateAssets>
       <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
     </PackageReference>