添加几个参数

AIStudio.Wpf.DiagramDesigner/Helpers/BitmapHelper.cs

@@ -1,4 +1,5 @@
 using System;
+using System.Collections;
 using System.Drawing;
 using System.Drawing.Imaging;
 using System.IO;
@@ -316,5 +317,15 @@ namespace AIStudio.Wpf.DiagramDesigner
                 return null;
             }
         }
+
+        public static Stream CopyStream(this Stream stream)
+        {
+            byte[] bytearray = new byte[stream.Length];
+            stream.Seek(0, SeekOrigin.Begin);
+            stream.Read(bytearray, 0, bytearray.Length);
+
+            var destination = new MemoryStream(bytearray);
+            return destination;
+        }
     }
 }