fix:墨迹纠正

Ink Canvas/Helpers/InkRecognizeHelper.cs

@@ -152,6 +152,9 @@ namespace Ink_Canvas.Helpers
 
             var node = legacy.InkDrawingNode;
             var shape = node.GetShape();
+            if (shape == null)
+                return InkShapeRecognitionResult.Empty;
+
             var hot = ClonePointCollection(node.HotPoints);
             return new InkShapeRecognitionResult(
                 node.GetShapeName(),
@@ -173,6 +176,9 @@ namespace Ink_Canvas.Helpers
 
         public static bool IsContainShapeType(string name)
         {
+            if (string.IsNullOrEmpty(name))
+                return false;
+
             if (name.Contains("Triangle") || name.Contains("Circle") ||
                 name.Contains("Rectangle") || name.Contains("Diamond") ||
                 name.Contains("Parallelogram") || name.Contains("Square")

Ink Canvas/Helpers/WinRtInkShapeRecognizer.cs

@@ -124,6 +124,9 @@ namespace Ink_Canvas.Helpers
                 return null;
 
             var da = stroke.DrawingAttributes;
+            if (da == null)
+                return null;
+
             var wda = new global::Windows.UI.Input.Inking.InkDrawingAttributes
             {
                 PenTip = global::Windows.UI.Input.Inking.PenTipShape.Circle,

Ink Canvas/MainWindow.xaml.cs

@@ -4492,6 +4492,9 @@ namespace Ink_Canvas
         {
             try
             {
+                if (!IsLoaded)
+                    return;
+
                 if (Settings.ModeSettings.IsPPTOnlyMode)
                 {
                     if (TrayTemporaryShowUntilUtc.HasValue && DateTime.UtcNow < TrayTemporaryShowUntilUtc.Value)