Add checks for CellPainting

Author: Ricardo Bossan (BEYONDSOFT CONSULTING INC) (from Dev Box)

src/System.Windows.Forms/src/System/Windows/Forms/Controls/DataGridView/DataGridViewCell.cs

@@ -3671,7 +3671,9 @@ internal void PaintWork(Graphics graphics,
             cellStyle,
             advancedBorderStyle,
             paintParts);
-        dataGridView.OnCellPainting(dgvcpe);
+
+        dataGridView?.OnCellPainting(dgvcpe);
+
         if (dgvcpe.Handled)
         {
             return;

src/System.Windows.Forms/src/System/Windows/Forms/Controls/DataGridView/DataGridViewCheckBoxCell.cs

@@ -839,9 +839,9 @@ protected override void OnKeyUp(KeyEventArgs e, int rowIndex)
                 e.Handled = true;
             }
 
-            NotifyMSAAClient(ColumnIndex, rowIndex);
+                NotifyMSAAClient(ColumnIndex, rowIndex);
+            }
         }
-    }
 
     protected override void OnLeave(int rowIndex, bool throughMouseClick)
     {
@@ -967,9 +967,12 @@ private void NotifyUiaClient()
 
     private void NotifyMSAAClient(int columnIndex, int rowIndex)
     {
-        Debug.Assert(DataGridView is not null);
-        Debug.Assert((columnIndex >= 0) && (columnIndex < DataGridView.Columns.Count));
-        Debug.Assert((rowIndex >= 0) && (rowIndex < DataGridView.Rows.Count));
+        if (DataGridView is null ||
+            columnIndex < 0 || columnIndex >= DataGridView.Columns.Count ||
+            rowIndex < 0 || rowIndex >= DataGridView.Rows.Count)
+        {
+            return;
+        }
 
         int visibleRowIndex = DataGridView.Rows.GetRowCount(DataGridViewElementStates.Visible, 0, rowIndex);
         int visibleColumnIndex = DataGridView.Columns.ColumnIndexToActualDisplayIndex(columnIndex, DataGridViewElementStates.Visible);
@@ -1043,7 +1046,11 @@ private Rectangle PaintPrivate(
         bool computeErrorIconBounds,
         bool paint)
     {
+        if(DataGridView is null)
         // Parameter checking.
+        {
+            return Rectangle.Empty;
+        }
 
         // One bit and one bit only should be turned on
         Debug.Assert(paint || computeContentBounds || computeErrorIconBounds);

src/System.Windows.Forms/src/System/Windows/Forms/Controls/DataGridView/DataGridViewRow.cs

@@ -786,9 +786,13 @@ private void BuildInheritedRowHeaderCellStyle(DataGridViewCellStyle inheritedCel
 
     private void BuildInheritedRowStyle(int rowIndex, DataGridViewCellStyle inheritedRowStyle)
     {
+        if (DataGridView is null)
+        {
+            return;
+        }
+
         Debug.Assert(inheritedRowStyle is not null);
         Debug.Assert(rowIndex >= 0);
-        Debug.Assert(DataGridView is not null);
 
         DataGridViewCellStyle? rowStyle = null;
         if (HasDefaultCellStyle)

src/System.Windows.Forms/src/System/Windows/Forms/Controls/DataGridView/DataGridViewRowHeaderCell.cs

@@ -653,6 +653,12 @@ private Rectangle PaintPrivate(
         bool cellSelected = (dataGridViewElementState & DataGridViewElementStates.Selected) != 0;
 
         Debug.Assert(DataGridView is not null);
+
+        if (DataGridView is null)
+        {
+            return Rectangle.Empty;
+        }
+
         if (DataGridView.ApplyVisualStylesToHeaderCells)
         {
             if (cellStyle.Padding != Padding.Empty)

src/System.Windows.Forms/src/System/Windows/Forms/Controls/DataGridView/DataGridViewTextBoxCell.cs

@@ -649,6 +649,11 @@ private Rectangle PaintPrivate(
         bool computeErrorIconBounds,
         bool paint)
     {
+        if (DataGridView is null)
+        {
+            return Rectangle.Empty;
+        }
+
         // Parameter checking. One bit and one bit only should be turned on.
         Debug.Assert(paint || computeContentBounds || computeErrorIconBounds);
         Debug.Assert(!paint || !computeContentBounds || !computeErrorIconBounds);