I need to change the color of the ProgressBar depending on the value I assign it. If the value is above 50, it should be green, if it's between 20 and 50, it should be yellow and if it's below 20, it should be red.

I found a great [answer](https://stackoverflow.com/a/9753302/1077789) here on how to change the color of the ProgressBar. I tested it and it works. However it's written as an extension method.

```
public static class ModifyProgressBarColor
{
    [DllImport("user32.dll", CharSet = CharSet.Auto, SetLastError = false)]
    static extern IntPtr SendMessage(IntPtr hWnd, uint Msg, IntPtr w, IntPtr l);
    public static void SetState(this ProgressBar pBar, int state)
    {
        SendMessage(pBar.Handle, 1040, (IntPtr)state, IntPtr.Zero);
    }
}

```

I want the color to change when you set the value for the `Value` property of the ProgressBar instead of having to manually assign it.

So I subclassed the ProgressBar class. Here's what I did.

```
using System.Runtime.InteropServices;
using System.Windows.Forms;

namespace MyApp
{
    class MyProgressBar: ProgressBar
    {
        [DllImport("user32.dll", CharSet = CharSet.Auto, SetLastError = false)]
        static extern IntPtr SendMessage(IntPtr hWnd, uint Msg, IntPtr w, IntPtr l);

        public int Value
        {
            set
            {
                if (value > 50)
                {
                    SendMessage(this.Handle, 1040, (IntPtr)1, IntPtr.Zero);
                }
                else if (value < 50 && value > 20)
                {
                    SendMessage(this.Handle, 1040, (IntPtr)2, IntPtr.Zero);
                }
                else if (value < 20)
                {
                    SendMessage(this.Handle, 1040, (IntPtr)3, IntPtr.Zero);
                }
            }
        }
    }
}

```

The control shows up in the Toolbox.

[![enter image description here](https://i.stack.imgur.com/fKpTv.png)](https://i.stack.imgur.com/fKpTv.png)

But when I set the `Value` in code, nothing shows up in the ProgressBar!

Any idea what I'm missing here?