修正 GraphicalOverlayComponent在所属控件 this.OnPaint(null) 时会抛出例外。

HZH_Controls/HZH_Controls/Controls/GraphicalOverlay/GraphicalOverlayComponent.cs

@@ -79,6 +79,8 @@ namespace HZH_Controls.Controls
 
 
         private void Control_Paint(object sender, PaintEventArgs e)
         private void Control_Paint(object sender, PaintEventArgs e)
         {
         {
+            if (e == null) return;
+
             // As each control on the form is repainted, this handler is called.
             // As each control on the form is repainted, this handler is called.
 
 
             Control control = sender as Control;
             Control control = sender as Control;