diff --git a/CPF.Windows/UnmanagedMethods.cs b/CPF.Windows/UnmanagedMethods.cs
index 07982fe..a087b14 100644
--- a/CPF.Windows/UnmanagedMethods.cs
+++ b/CPF.Windows/UnmanagedMethods.cs
@@ -1490,8 +1490,10 @@ BLENDFUNCTION blendFunction // alpha-blending function
         //[DllImport("shell32.dll", CharSet = CharSet.Auto)]
         //public static extern int DragQueryFile(HandleRef hDrop, int iFile, StringBuilder lpszFile, int cch);
 
-        [DllImport("dwmapi.dll", PreserveSig = false)]
-        public static extern bool DwmIsCompositionEnabled();
+        //[DllImport("dwmapi.dll", PreserveSig = false)]
+        //public static extern bool DwmIsCompositionEnabled();
+        [DllImport("dwmapi.dll", BestFitMapping = false)]
+        public static extern int DwmIsCompositionEnabled(out Int32 enabled);
 
         [DllImport("dwmapi.dll")]
         public static extern int DwmEnableBlurBehindWindow(IntPtr hWnd, ref DWM_BLURBEHIND pBlurBehind);
diff --git a/CPF.Windows/WindowImpl.cs b/CPF.Windows/WindowImpl.cs
index 1a02deb..eeb31fe 100644
--- a/CPF.Windows/WindowImpl.cs
+++ b/CPF.Windows/WindowImpl.cs
@@ -83,7 +83,7 @@ namespace CPF.Windows
             }
             posttime = Application.Elapsed;
             var v = System.Environment.OSVersion.Version;
-            if (v.Major >= 6 && DwmIsCompositionEnabled() && !Application.DesignMode)
+            if (v.Major >= 6 && DwmIsCompositionEnabled(out var e) == 0 && e == 1 && !Application.DesignMode)
             {
             }
             else
@@ -92,7 +92,7 @@ namespace CPF.Windows
             }
             if ((v.Major == 6 && v.Minor < 2))
             {
-               touchMsg =  RegisterTouchWindow(handle, RegisterTouchFlags.TWF_NONE);
+                touchMsg = RegisterTouchWindow(handle, RegisterTouchFlags.TWF_NONE);
             }
             _className = "CPFWindow-" + Guid.NewGuid();
             // 初始化窗口类结构  
diff --git a/CPF/Binding.cs b/CPF/Binding.cs
index d72013f..d217983 100644
--- a/CPF/Binding.cs
+++ b/CPF/Binding.cs
@@ -620,7 +620,7 @@ namespace CPF
                 throw new Exception($"错误:{ex}");
             }
         }
-        CpfObject SourceProperty = null;
+        //CpfObject SourceProperty = null;
         private void Target_PropertyChanged(object sender, PropertyChangedEventArgs e)
         {
             //重新绑定
diff --git a/CPF/Json/Reflection.cs b/CPF/Json/Reflection.cs
index 0ddda5d..e5a9892 100644
--- a/CPF/Json/Reflection.cs
+++ b/CPF/Json/Reflection.cs
@@ -163,6 +163,10 @@ namespace CPF.Json
             {
                 sd = new Dictionary<string, myPropInfo>();
                 var bf = BindingFlags.Public | BindingFlags.Instance | BindingFlags.Static;
+                if (type.Name == "Nullable`1")
+                {
+                    type = type.GetGenericArguments()[0];
+                }
                 PropertyInfo[] pr = type.GetProperties(bf);
                 foreach (PropertyInfo p in pr)
                 {
@@ -317,16 +321,26 @@ namespace CPF.Json
                     }
                     else // structs
                     {
-                        DynamicMethod dynMethod = new DynamicMethod("_", typeof(object), null);
-                        ILGenerator ilGen = dynMethod.GetILGenerator();
-                        var lv = ilGen.DeclareLocal(objtype);
-                        ilGen.Emit(OpCodes.Ldloca_S, lv);
-                        ilGen.Emit(OpCodes.Initobj, objtype);
-                        ilGen.Emit(OpCodes.Ldloc_0);
-                        ilGen.Emit(OpCodes.Box, objtype);
-                        ilGen.Emit(OpCodes.Ret);
-                        c = (CreateObject)dynMethod.CreateDelegate(typeof(CreateObject));
-                        _constrcache.Add(objtype, c);
+                        if (objtype.Name == "Nullable`1")
+                        {
+                            var sType = objtype.GetGenericArguments()[0];
+                            var create = objtype.GetConstructor(new Type[] { sType });
+                            c = () => create.Invoke(new object[] { null });
+                            _constrcache.Add(objtype, c);
+                        }
+                        else
+                        {
+                            DynamicMethod dynMethod = new DynamicMethod("_", typeof(object), null);
+                            ILGenerator ilGen = dynMethod.GetILGenerator();
+                            var lv = ilGen.DeclareLocal(objtype);
+                            ilGen.Emit(OpCodes.Ldloca_S, lv);
+                            ilGen.Emit(OpCodes.Initobj, objtype);
+                            ilGen.Emit(OpCodes.Ldloc_0);
+                            ilGen.Emit(OpCodes.Box, objtype);
+                            ilGen.Emit(OpCodes.Ret);
+                            c = (CreateObject)dynMethod.CreateDelegate(typeof(CreateObject));
+                            _constrcache.Add(objtype, c);
+                        }
                     }
                     return c();
                 }
diff --git a/CPF/Platform/Application.cs b/CPF/Platform/Application.cs
index 1fe0532..1c8deb1 100644
--- a/CPF/Platform/Application.cs
+++ b/CPF/Platform/Application.cs
@@ -228,6 +228,11 @@ namespace CPF.Platform
             get;
             set;
         }
+        /// <summary>
+        /// 某些平台下不能使用CPF的消息循环，需要将该属性改成false
+        /// </summary>
+        public static bool NeedRunLoop { get; set; } = true;
+
 //#if NETSTANDARD
 //        /// <summary>
 //        /// 启用AOT功能，net5以及以上版本才能使用，其中包括，禁用弱引用事件功能，一般在Aot的release发布的时候设置。如果不用Aot，请勿设置，否则可能有内存泄露风险，而且会导致性能降低。 以及切换windows的com包装
diff --git a/CPF/Threading/DispatcherTimer.cs b/CPF/Threading/DispatcherTimer.cs
index 15b234f..169aaba 100644
--- a/CPF/Threading/DispatcherTimer.cs
+++ b/CPF/Threading/DispatcherTimer.cs
@@ -46,7 +46,7 @@ namespace CPF.Threading
             if (timeThread == null)
             {
                 timers = new List<DispatcherTimer>();
-                tempTimers = new List<DispatcherTimer>(); 
+                tempTimers = new List<DispatcherTimer>();
                 timeThread = new Thread(SetTime) { IsBackground = true, Name = "定时器线程" };
                 timeThread.Start();
             }
@@ -100,7 +100,7 @@ namespace CPF.Threading
                 }
                 if (tempTimers.Count > 0)
                 {
-                    if (CPF.Platform.Application.Main != null)
+                    if ((CPF.Platform.Application.NeedRunLoop && CPF.Platform.Application.Main != null) || !CPF.Platform.Application.NeedRunLoop)
                     {
                         Dispatcher.MainThread.Invoke(() =>
                         {