dotnet
diff --git a/‎src/Microsoft.DotNet.Wpf/src/PresentationCore/System/Windows/Media/Imaging/WriteableBitmap.cs
Lines changed: 16 additions & 30 deletions b/‎src/Microsoft.DotNet.Wpf/src/PresentationCore/System/Windows/Media/Imaging/WriteableBitmap.cs
Lines changed: 16 additions & 30 deletions
@@ -318,6 +318,11 @@ ref lockBufferStride
         ///   on the back buffer and request a render pass.
         /// </summary>
         public void Unlock()
+        {
+            UnlockInner();
+        }
+
+        private void UnlockInner(bool shouldSubscribeToCommittingBatch = true)
         {
             WritePreamble();
 
@@ -334,34 +339,23 @@ public void Unlock()
                 _pBackBufferLock.Dispose();
                 _pBackBufferLock = null;
 
-                if (_hasDirtyRects)
+                if(shouldSubscribeToCommittingBatch)
                 {
-                    SubscribeToCommittingBatch();
-
-                    //
-                    // Notify listeners that we have changed.
-                    //
-                    WritePostscript();
+                    SubscribeToCommittingBatchAndWritePostscript();
                 }
             }
         }
 
-        private void UnlockWithoutSubscribeToCommittingBatch()
+        private void SubscribeToCommittingBatchAndWritePostscript()
         {
-            WritePreamble();
-
-            if (_lockCount == 0)
+            if (_hasDirtyRects)
             {
-                throw new InvalidOperationException(SR.Get(SRID.Image_MustBeLocked));
-            }
-            Invariant.Assert(_lockCount > 0, "Lock count should never be negative!");
+                SubscribeToCommittingBatch();
 
-            _lockCount--;
-            if (_lockCount == 0)
-            {
-                // This makes the back buffer read-only.
-                _pBackBufferLock.Dispose();
-                _pBackBufferLock = null;
+                //
+                // Notify listeners that we have changed.
+                //
+                WritePostscript();
             }
         }
 
@@ -814,18 +808,10 @@ out _pDoubleBufferedBitmap
                 source.CriticalCopyPixels(rcFull, _backBuffer, bufferSize, _backBufferStride.Value);
                 AddDirtyRect(rcFull);
 
-                UnlockWithoutSubscribeToCommittingBatch();
+                UnlockInner(shouldSubscribeToCommittingBatch: false);
             }
 
-            if (_hasDirtyRects)
-            {
-                SubscribeToCommittingBatch();
-
-                //
-                // Notify listeners that we have changed.
-                //
-                WritePostscript();
-            }
+            SubscribeToCommittingBatchAndWritePostscript();
 
             EndInit();
         }