Visual Studio 2012 C# Transparent Overlay Panel

Posted on Wednesday, February 5, 2014

I recently had a need to overlay a warning over all the tools I had displayed on a Panel.   Basically I wanted a transparent image over the entire panel that said something like "Warning" over and over again.

This guide will be a complete step by step on how to accomplish this.

From Visual Studio 2013 click on File -> New -> Project
To create a new project.

Choose a Windows Forms Application and click OK

Drag and drop a few buttons on the Form.

Drag and Drop a Data Grid View as well.

Click Edit Columns

Click Add

Set the Header Text and Click Add

Add a few more Column Names like this

Click Cancel when you are done

Click OK to close it out

Add a few labels on their

Click Start to run it and see what we got.


Create the Custom Panel Class

Right click on your Windows application and select Add -> Class

Select Class
Name it


And click Add

Update the code to the following

using System;
using System.Collections.Generic;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;

namespace WindowsFormsApplication1 {
    class TransparentMessagePanel : Panel {

        protected override CreateParams CreateParams {
            get {
                CreateParams cp = base.CreateParams;
                cp.ExStyle |= 0x00000020; // WS_EX_TRANSPARENT
                return cp;

        protected override void OnPaintBackground(PaintEventArgs e) {

        protected override void OnPaint(PaintEventArgs e) {
            Graphics g = e.Graphics;
            Font font = new Font("Microsoft Sans Serif", 36F,
            SizeF stringSize = new SizeF();
            String str = "";
            int rowHeight;
            int textWidth;
            int xAdjust = 0;

            stringSize = e.Graphics.MeasureString(str, font, 800);
            rowHeight = (int)stringSize.Height +
            textWidth = ((int)stringSize.Width);

            for (int x = 0; x <
                    (this.Width / textWidth) + 2; x++) {
                for (int y = 0; y < 2 *
                         (this.Height / rowHeight) + 2; y++) {
                    xAdjust = textWidth / 2;
                    g.DrawString(str, font,
                       new Point(x * textWidth - xAdjust,
                             y * rowHeight));

Save the file and recompile

Click on Start

Now the TransparentMessagePanel has been compiled it will show up in the toolbox.

Search for Transpar to shorten the list.

Add A TransparentMessagePanel to the Form and resize it to overlay all the other components.

Click on Start to run

That worked, but I can't click on any of the buttons as they are behind this TransparentMessagePanel  To fix this do the following….

Select the TransparenteMessagePanel and in its properties select Enabled to False.

Click on Start to run

Now you can click through on any of the other components.

There you go a transparent panel to overlay other components that you can click through.


[1]  How can I set the opacity or transparency of a Panel in WinForms?
       Visited 2/2014


  1. I got this to work in Visual Studio 2012, the TransparentMessagePanel pops up immediately after build in the toolbox. This is not the case for Visual Studio 2013. In your instructions you say, 'From Visual Studio 2013 click on File -> New -> Project' ... So is this template for VS12 or VS13? Thank you.

  2. I found a fix. In Visual Studio 2013. Go to Tools > Options > Windows Forms Designer > General
    At the bottom of the list you'll find Toolbox > AutoToolboxPopulate which on a fresh install defaults to False. Set it true and then rebuild your solution. Good luck to the next person!

    1. Thanks for leaving that, I am sure it will help the next guy :)

  3. The panel is very slow and it does not look like it should be,