Move from IntPtr to nint to avoid runtime casting errors. (#5791)

We still had a number of potential and actual overflow scenarios. In order to make this more resilient, move SendMessage, PostMessage, and Get/SetWindowLong from IntPtr to nint.

This also makes things slightly faster as we aren't creating IntPtr structs and invoking the cast methods on it.

Note that IntPtr implicitly converts to nint. I've removed most of the actual IntPtr usages. I've also removed most of the HandleRef overloads and vetted the callers to do the right thing in regards to avoiding finalizer issues.

There is more we can do here, but this is a big first step.

Also clean up DateTimePicker and move SYSTEMTIME converters to SYSTEMTIME.

I've tried to remove all (IntPtr) casts in SendMessage calls.

src/System.Windows.Forms.Design/src/System/ComponentModel/Design/DesignerActionPanel.EditorPropertyLine.cs

@@ -608,7 +608,7 @@ public void ShowDropDown(Control parent)
                         IntPtr hWndCapture = User32.GetCapture();
                         if (hWndCapture != IntPtr.Zero)
                         {
-                            User32.SendMessageW(hWndCapture, User32.WM.CANCELMODE, IntPtr.Zero, IntPtr.Zero);
+                            User32.SendMessageW(hWndCapture, User32.WM.CANCELMODE);
                             User32.ReleaseCapture();
                         }
 

src/System.Windows.Forms.Design/src/System/ComponentModel/Design/ObjectSelectorEditor.cs

@@ -72,7 +72,7 @@ public static void ApplyTreeViewThemeStyles(TreeView treeView)
             IntPtr hwnd = treeView.Handle;
             ComCtl32.TVS_EX exstyle = (ComCtl32.TVS_EX)User32.SendMessageW(hwnd, (User32.WM)ComCtl32.TVM.GETEXTENDEDSTYLE);
             exstyle |= ComCtl32.TVS_EX.DOUBLEBUFFER | ComCtl32.TVS_EX.FADEINOUTEXPANDOS;
-            User32.SendMessageW(hwnd, (User32.WM)ComCtl32.TVM.SETEXTENDEDSTYLE, IntPtr.Zero, (IntPtr)exstyle);
+            User32.SendMessageW(hwnd, (User32.WM)ComCtl32.TVM.SETEXTENDEDSTYLE, 0, (nint)exstyle);
         }
 
         public override UITypeEditorEditStyle GetEditStyle(ITypeDescriptorContext context) => UITypeEditorEditStyle.DropDown;

src/System.Windows.Forms.Design/src/System/Windows/Forms/Design/Behavior/ResizeBehavior.cs

@@ -618,7 +618,7 @@ public override bool OnMouseMove(Glyph g, MouseButtons button, Point mouseLoc)
                 Rectangle oldBorderRect = BehaviorService.ControlRectInAdornerWindow(control);
                 bool needToUpdate = true;
                 // The ResizeBehavior can easily get into a situation where we are fighting with a layout engine. E.g., We resize control to 50px, LayoutEngine lays out and finds 50px was too small and resized back to 100px.  This is what should happen, but it looks bad in the designer.  To avoid the flicker we temporarily turn off painting while we do the resize.
-                User32.SendMessageW(control, User32.WM.SETREDRAW, PARAM.FromBool(false));
+                User32.SendMessageW(control, User32.WM.SETREDRAW, (nint)BOOL.FALSE);
                 try
                 {
                     bool fRTL = false;
@@ -772,7 +772,7 @@ public override bool OnMouseMove(Glyph g, MouseButtons button, Point mouseLoc)
                 finally
                 {
                     // While we were resizing we discarded painting messages to reduce flicker.  We now turn painting back on and manually refresh the controls.
-                    User32.SendMessageW(control, User32.WM.SETREDRAW, PARAM.FromBool(true));
+                    User32.SendMessageW(control, User32.WM.SETREDRAW, (nint)BOOL.TRUE);
                     //update the control
                     if (needToUpdate)
                     {

src/System.Windows.Forms.Design/src/System/Windows/Forms/Design/CommandSet.cs

@@ -782,7 +782,7 @@ protected virtual bool OnKeyCancel(object sender)
                     IntPtr hwnd = User32.WindowFromPoint(p);
                     if (hwnd != IntPtr.Zero)
                     {
-                        User32.SendMessageW(hwnd, User32.WM.SETCURSOR, hwnd, (IntPtr)User32.HT.CLIENT);
+                        User32.SendMessageW(hwnd, User32.WM.SETCURSOR, hwnd, (nint)User32.HT.CLIENT);
                     }
                     else
                     {

src/System.Windows.Forms.Design/src/System/Windows/Forms/Design/ControlDesigner.cs

@@ -1950,7 +1950,7 @@ protected unsafe virtual void WndProc(ref Message m)
 
                     // We don't really want the focus, but we want to focus the designer. Below we handle WM_SETFOCUS
                     // and do the right thing.
-                    User32.SendMessageW(Control.Handle, User32.WM.SETFOCUS, IntPtr.Zero, IntPtr.Zero);
+                    User32.SendMessageW(Control.Handle, User32.WM.SETFOCUS);
 
                     // We simulate doubleclick for things that don't...
                     if (button == MouseButtons.Left && IsDoubleClick(x, y))
@@ -1984,7 +1984,7 @@ protected unsafe virtual void WndProc(ref Message m)
 
                         if (_toolPassThrough)
                         {
-                            User32.SendMessageW(Control.Parent.Handle, (User32.WM)m.Msg, m.WParam, (IntPtr)GetParentPointFromLparam(m.LParam));
+                            User32.SendMessageW(Control.Parent.Handle, (User32.WM)m.Msg, m.WParam, GetParentPointFromLparam(m.LParam));
                             return;
                         }
 
@@ -2033,7 +2033,7 @@ protected unsafe virtual void WndProc(ref Message m)
                                 Control.Parent.Handle,
                                 (User32.WM)m.Msg,
                                 m.WParam,
-                                (IntPtr)GetParentPointFromLparam(m.LParam));
+                                GetParentPointFromLparam(m.LParam));
                             return;
                         }
 
@@ -2080,7 +2080,7 @@ protected unsafe virtual void WndProc(ref Message m)
                                 Control.Parent.Handle,
                                 (User32.WM)m.Msg,
                                 m.WParam,
-                                (IntPtr)GetParentPointFromLparam(m.LParam));
+                                GetParentPointFromLparam(m.LParam));
                             _toolPassThrough = false;
                             return;
                         }

src/System.Windows.Forms.Design/src/System/Windows/Forms/Design/DesignerFrame.cs

@@ -105,7 +105,7 @@ private unsafe void ForceDesignerRedraw(bool focus)
         {
             if (_designer != null && _designer.IsHandleCreated)
             {
-                User32.SendMessageW(_designer.Handle, User32.WM.NCACTIVATE, PARAM.FromBool(focus), IntPtr.Zero);
+                User32.SendMessageW(_designer.Handle, User32.WM.NCACTIVATE, PARAM.FromBool(focus));
                 User32.RedrawWindow(_designer.Handle, null, IntPtr.Zero, User32.RDW.FRAME);
             }
         }
@@ -256,7 +256,7 @@ protected override void WndProc(ref Message m)
                     if ((msg == User32.WM.VSCROLL) || (msg == User32.WM.HSCROLL))
                     {
                         // Send a message to ourselves to scroll
-                        User32.SendMessageW(_designerRegion.Handle, msg, (IntPtr)PARAM.ToInt((int)wScrollNotify, 0), IntPtr.Zero);
+                        User32.SendMessageW(_designerRegion.Handle, msg, PARAM.ToInt((int)wScrollNotify, 0));
                         return;
                     }
 

src/System.Windows.Forms.Design/src/System/Windows/Forms/Design/DesignerUtils.cs

@@ -438,30 +438,33 @@ public static bool GenerateSnapShotWithWM_PRINT(Control control, ref Image image
             IntPtr hWnd = control.Handle;
             image = new Bitmap(Math.Max(control.Width, MINCONTROLBITMAPSIZE), Math.Max(control.Height, MINCONTROLBITMAPSIZE), PixelFormat.Format32bppPArgb);
 
-            //Have to do this BEFORE we set the testcolor.
+            // Have to do this BEFORE we set the testcolor.
             if (control.BackColor == Color.Transparent)
             {
-                using (Graphics g = Graphics.FromImage(image))
-                {
-                    g.Clear(SystemColors.Control);
-                }
+                using Graphics g = Graphics.FromImage(image);
+                g.Clear(SystemColors.Control);
             }
 
-            // To validate that the control responded to the wm_print message, we pre-populate the bitmap with a colored center pixel.  We assume that the control _did not_ respond to wm_print if these center pixel is still this value
+            //  To validate that the control responded to the wm_print message, we pre-populate the bitmap with a
+            //  colored center pixel.  We assume that the control _did not_ respond to wm_print if these center pixel
+            //  is still this value.
+
             Color testColor = Color.FromArgb(255, 252, 186, 238);
             ((Bitmap)image).SetPixel(image.Width / 2, image.Height / 2, testColor);
             using (Graphics g = Graphics.FromImage(image))
             {
                 IntPtr hDc = g.GetHdc();
-                //send the actual wm_print message
-                User32.SendMessageW(hWnd, User32.WM.PRINT, hDc, (IntPtr)(User32.PRF.CHILDREN | User32.PRF.CLIENT | User32.PRF.ERASEBKGND | User32.PRF.NONCLIENT));
+                User32.SendMessageW(
+                    hWnd,
+                    User32.WM.PRINT,
+                    hDc,
+                    (nint)(User32.PRF.CHILDREN | User32.PRF.CLIENT | User32.PRF.ERASEBKGND | User32.PRF.NONCLIENT));
                 g.ReleaseHdc(hDc);
             }
 
-            //now check to see if our center pixel was cleared, if not then our wm_print failed
+            // Now check to see if our center pixel was cleared, if not then our WM_PRINT failed
             if (((Bitmap)image).GetPixel(image.Width / 2, image.Height / 2).Equals(testColor))
             {
-                //wm_print failed
                 return false;
             }
 
@@ -863,9 +866,7 @@ private static int ScaleLogicalToDeviceUnitsX(int unit)
             => DpiHelper.IsScalingRequired ? DpiHelper.LogicalToDeviceUnitsX(unit) : unit;
 
         private static ComCtl32.TVS_EX TreeView_GetExtendedStyle(IntPtr handle)
-        {
-            return (ComCtl32.TVS_EX)User32.SendMessageW(handle, (User32.WM)ComCtl32.TVM.GETEXTENDEDSTYLE);
-        }
+            => (ComCtl32.TVS_EX)User32.SendMessageW(handle, (User32.WM)ComCtl32.TVM.GETEXTENDEDSTYLE);
 
         /// <summary>
         ///  Modify a WinForms TreeView control to use the new Explorer style theme
@@ -884,7 +885,7 @@ public static void ApplyTreeViewThemeStyles(TreeView treeView)
             UxTheme.SetWindowTheme(hwnd, "Explorer", null);
             ComCtl32.TVS_EX exstyle = TreeView_GetExtendedStyle(hwnd);
             exstyle |= ComCtl32.TVS_EX.DOUBLEBUFFER | ComCtl32.TVS_EX.FADEINOUTEXPANDOS;
-            User32.SendMessageW(hwnd, (User32.WM)ComCtl32.TVM.SETEXTENDEDSTYLE, IntPtr.Zero, (IntPtr)exstyle);
+            User32.SendMessageW(hwnd, (User32.WM)ComCtl32.TVM.SETEXTENDEDSTYLE, 0, (nint)exstyle);
         }
 
         /// <summary>
@@ -900,7 +901,11 @@ public static void ApplyListViewThemeStyles(ListView listView)
 
             IntPtr hwnd = listView.Handle;
             UxTheme.SetWindowTheme(hwnd, "Explorer", null);
-            User32.SendMessageW(hwnd, (User32.WM)ComCtl32.LVM.SETEXTENDEDLISTVIEWSTYLE, (IntPtr)ComCtl32.LVS_EX.DOUBLEBUFFER, (IntPtr)ComCtl32.LVS_EX.DOUBLEBUFFER);
+            User32.SendMessageW(
+                hwnd,
+                (User32.WM)ComCtl32.LVM.SETEXTENDEDLISTVIEWSTYLE,
+                (nint)ComCtl32.LVS_EX.DOUBLEBUFFER,
+                (nint)ComCtl32.LVS_EX.DOUBLEBUFFER);
         }
     }
 }

src/System.Windows.Forms.Design/src/System/Windows/Forms/Design/DocumentDesigner.cs

@@ -1206,9 +1206,9 @@ private void OnDesignerActivate(object source, EventArgs evevent)
         private unsafe void OnDesignerDeactivate(object sender, EventArgs e)
         {
             Control control = Control;
-            if (control != null && control.IsHandleCreated)
+            if (control is not null && control.IsHandleCreated)
             {
-                User32.SendMessageW(control.Handle, User32.WM.NCACTIVATE);
+                User32.SendMessageW(control.Handle, User32.WM.NCACTIVATE, (nint)BOOL.FALSE);
                 User32.RedrawWindow(control.Handle, null, IntPtr.Zero, User32.RDW.FRAME);
             }
         }

src/System.Windows.Forms.Design/src/System/Windows/Forms/Design/FormDocumentDesigner.cs

@@ -379,7 +379,7 @@ private unsafe void OnDesignerActivate(object source, EventArgs evevent)
             Control control = Control;
             if (control != null && control.IsHandleCreated)
             {
-                User32.SendMessageW(control.Handle, User32.WM.NCACTIVATE, (IntPtr)1, IntPtr.Zero);
+                User32.SendMessageW(control.Handle, User32.WM.NCACTIVATE, (nint)BOOL.TRUE);
                 User32.RedrawWindow(control.Handle, null, IntPtr.Zero, User32.RDW.FRAME);
             }
         }
@@ -392,7 +392,7 @@ private unsafe void OnDesignerDeactivate(object sender, EventArgs e)
             Control control = Control;
             if (control != null && control.IsHandleCreated)
             {
-                User32.SendMessageW(control.Handle, User32.WM.NCACTIVATE, IntPtr.Zero, IntPtr.Zero);
+                User32.SendMessageW(control.Handle, User32.WM.NCACTIVATE, (nint)BOOL.FALSE);
                 User32.RedrawWindow(control.Handle, null, IntPtr.Zero, User32.RDW.FRAME);
             }
         }

src/System.Windows.Forms.Design/src/System/Windows/Forms/Design/ListBoxDesigner.cs

@@ -195,7 +195,7 @@ private void UpdateControlName(string name)
             if (lb.IsHandleCreated && lb.Items.Count == 0)
             {
                 User32.SendMessageW(lb, (User32.WM)User32.LB.RESETCONTENT);
-                User32.SendMessageW(lb, (User32.WM)User32.LB.ADDSTRING, IntPtr.Zero, name);
+                User32.SendMessageW(lb, (User32.WM)User32.LB.ADDSTRING, 0, name);
             }
         }
 

src/System.Windows.Forms.Design/src/System/Windows/Forms/Design/ListViewDesigner.cs

@@ -67,11 +67,10 @@ private View View
             }
         }
 
-        /// <summary>
-        ///  We override GetHitTest to make the header in report view UI-active.
-        /// </summary>
         protected unsafe override bool GetHitTest(Point point)
         {
+            // We override GetHitTest to make the header in report view UI-active.
+
             ListView listView = (ListView)Component;
             if (listView.View == View.Details)
             {
@@ -85,7 +84,7 @@ protected unsafe override bool GetHitTest(Point point)
                     {
                         User32.MapWindowPoints(IntPtr.Zero, headerHwnd, &point, 1);
                         _hdrhit.pt = point;
-                        User32.SendMessageW(headerHwnd, (User32.WM)ComCtl32.HDM.HITTEST, IntPtr.Zero, ref _hdrhit);
+                        User32.SendMessageW(headerHwnd, (User32.WM)ComCtl32.HDM.HITTEST, 0, ref _hdrhit);
                         if (_hdrhit.flags == ComCtl32.HHT.ONDIVIDER)
                             return true;
                     }

src/System.Windows.Forms.Design/src/System/Windows/Forms/Design/MaskDesignerDialog.cs

@@ -484,7 +484,7 @@ private void UpdateSortedListView(MaskDescriptorComparer.SortType sortType)
             // Since we need to pre-process each item before inserting it in the ListView, it is better to remove all items
             // from it first and then add the sorted ones back (no replace).  Stop redrawing while we change the list.
 
-            User32.SendMessageW(_listViewCannedMasks, User32.WM.SETREDRAW, PARAM.FromBool(false));
+            User32.SendMessageW(_listViewCannedMasks, User32.WM.SETREDRAW, (nint)BOOL.FALSE);
 
             try
             {
@@ -518,7 +518,7 @@ private void UpdateSortedListView(MaskDescriptorComparer.SortType sortType)
             finally
             {
                 // Resume redraw.
-                User32.SendMessageW(_listViewCannedMasks, User32.WM.SETREDRAW, PARAM.FromBool(true));
+                User32.SendMessageW(_listViewCannedMasks, User32.WM.SETREDRAW, (nint)BOOL.TRUE);
                 _listViewCannedMasks.Invalidate();
             }
         }

src/System.Windows.Forms.Design/src/System/Windows/Forms/Design/OleDragDropHandler.cs

@@ -891,17 +891,13 @@ public void DoOleDragDrop(DragEventArgs de)
 
                                 try
                                 {
-                                    name = null;
-                                    if (comp.Site != null)
-                                    {
-                                        name = comp.Site.Name;
-                                    }
+                                    name = comp.Site?.Name;
 
                                     Control oldDesignerControl = null;
                                     if (updateLocation)
                                     {
                                         oldDesignerControl = client.GetDesignerControl();
-                                        User32.SendMessageW(oldDesignerControl.Handle, User32.WM.SETREDRAW);
+                                        User32.SendMessageW(oldDesignerControl.Handle, User32.WM.SETREDRAW, (nint)BOOL.FALSE);
                                     }
 
                                     Point dropPt = client.GetDesignerControl().PointToClient(new Point(de.X, de.Y));
@@ -950,10 +946,10 @@ public void DoOleDragDrop(DragEventArgs de)
                                         }
                                     }
 
-                                    if (oldDesignerControl != null)
+                                    if (oldDesignerControl is not null)
                                     {
                                         //((ComponentDataObject)dataObj).ShowControls();
-                                        User32.SendMessageW(oldDesignerControl.Handle, User32.WM.SETREDRAW, (IntPtr)1);
+                                        User32.SendMessageW(oldDesignerControl.Handle, User32.WM.SETREDRAW, (nint)BOOL.TRUE);
                                         oldDesignerControl.Invalidate(true);
                                     }
 

src/System.Windows.Forms.Design/src/System/Windows/Forms/Design/ScrollableControlDesigner.cs

@@ -28,12 +28,11 @@ protected override bool GetHitTest(Point pt)
                 return true;
             }
 
-            // The scroll bars on a form are "live"
-            //
+            // The scroll bars on a form are "live".
             ScrollableControl f = (ScrollableControl)Control;
             if (f.IsHandleCreated && f.AutoScroll)
             {
-                int hitTest = (int)(long)User32.SendMessageW(f.Handle, User32.WM.NCHITTEST, IntPtr.Zero, PARAM.FromLowHigh(pt.X, pt.Y));
+                int hitTest = (int)User32.SendMessageW(f.Handle, User32.WM.NCHITTEST, 0, PARAM.FromLowHigh(pt.X, pt.Y));
                 if (hitTest == (int)User32.HT.VSCROLL || hitTest == (int)User32.HT.HSCROLL)
                 {
                     return true;

src/System.Windows.Forms.Design/src/System/Windows/Forms/Design/ToolStripTemplateNode.cs

@@ -909,12 +909,12 @@ private void EnterInSituEdit()
                     tb.KeyDown += new KeyEventHandler(OnKeyDown);
                     tb.SelectAll();
                     Control baseComponent = null;
-                    if (_designerHost != null)
+                    if (_designerHost is not null)
                     {
                         baseComponent = (Control)_designerHost.RootComponent;
-                        User32.SendMessageW(baseComponent.Handle, User32.WM.SETREDRAW, IntPtr.Zero, IntPtr.Zero);
+                        User32.SendMessageW(baseComponent.Handle, User32.WM.SETREDRAW, (nint)BOOL.FALSE);
                         tb.Focus();
-                        User32.SendMessageW(baseComponent.Handle, User32.WM.SETREDRAW, (IntPtr)1, IntPtr.Zero);
+                        User32.SendMessageW(baseComponent.Handle, User32.WM.SETREDRAW, (nint)BOOL.TRUE);
                     }
                 }
                 finally
@@ -994,15 +994,13 @@ internal void FocusEditor(ToolStripItem currentItem)
         /// </summary>
         private void FocusForm()
         {
-            if (_component.Site.GetService(typeof(ISplitWindowService)) is DesignerFrame designerFrame)
+            if (_component.Site.GetService(typeof(ISplitWindowService)) is DesignerFrame designerFrame
+                && _designerHost is not null)
             {
-                if (_designerHost != null)
-                {
-                    Control baseComponent = (Control)_designerHost.RootComponent;
-                    User32.SendMessageW(baseComponent.Handle, User32.WM.SETREDRAW, IntPtr.Zero, IntPtr.Zero);
-                    designerFrame.Focus();
-                    User32.SendMessageW(baseComponent.Handle, User32.WM.SETREDRAW, (IntPtr)1, IntPtr.Zero);
-                }
+                Control baseComponent = (Control)_designerHost.RootComponent;
+                User32.SendMessageW(baseComponent.Handle, User32.WM.SETREDRAW, (nint)BOOL.FALSE);
+                designerFrame.Focus();
+                User32.SendMessageW(baseComponent.Handle, User32.WM.SETREDRAW, (nint)BOOL.TRUE);
             }
         }