[ImageResizer]Check for files in HDropIterator before processing (#20985)

Author: stefansjfw

src/common/utils/HDropIterator.h

@@ -7,6 +7,7 @@ class HDropIterator
     HDropIterator(IDataObject* pDataObject)
     {
         _current = 0;
+        _listCount = 0;
 
         FORMATETC formatetc = {
             CF_HDROP,
@@ -16,14 +17,22 @@ class HDropIterator
             TYMED_HGLOBAL
         };
 
-        pDataObject->GetData(&formatetc, &m_medium);
-
-        _listCount = DragQueryFile((HDROP)m_medium.hGlobal, 0xFFFFFFFF, NULL, 0);
+        if (SUCCEEDED(pDataObject->GetData(&formatetc, &m_medium)))
+        {
+            _listCount = DragQueryFile((HDROP)m_medium.hGlobal, 0xFFFFFFFF, NULL, 0);
+        }
+        else
+        {
+            m_medium = {};
+        }
     }
 
     ~HDropIterator()
     {
-        ReleaseStgMedium(&m_medium);
+        if (m_medium.tymed)
+        {
+            ReleaseStgMedium(&m_medium);
+        }
     }
 
     void First()

src/modules/imageresizer/dll/ContextMenuHandler.cpp

@@ -72,6 +72,11 @@ HRESULT CContextMenuHandler::QueryContextMenu(_In_ HMENU hmenu, UINT indexMenu,
     // NB: We just check the first item. We could iterate through more if the first one doesn't meet the criteria
     HDropIterator i(m_pdtobj);
     i.First();
+    if (i.IsDone())
+    {
+        return S_OK;
+    }
+
 // Suppressing C26812 warning as the issue is in the shtypes.h library
 #pragma warning(suppress : 26812)
     PERCEIVED type;