watermark textbox

[AngelicOne]

I read some articles with regards on watermarks in windows app, but I found it to be quite complicated. What is the best way to implement watermark in textboxes?

[Momerath]

Add this:

public static class TextBoxWatermarkExtensionMethod {
    private const uint ECM_FIRST = 0x1500;
    private const uint EM_SETCUEBANNER = ECM_FIRST + 1;

    [DllImport("user32.dll", CharSet = CharSet.Auto, SetLastError = false)]
    private static extern IntPtr SendMessage(IntPtr hWnd, uint Msg, uint wParam, [MarshalAs(UnmanagedType.LPWStr)] string lParam);

    public static void SetWatermark(this TextBox textBox, string watermarkText) {
        SendMessage(textBox.Handle, EM_SETCUEBANNER, 0, watermarkText);
    }
}

After that you can do this:

myTextbox.SetWatermark("This is the watermark");

[AngelicOne]

Thanks. That's easy compared to sub classing it.

[AngelicOne]

Hello, i'm sorry if this is late but where could I call the watermark class for my textbox? Tried in my form's load event but it's not present.

[Momerath]

If it isn't present then you didn't include the above code correctly.

[AngelicOne]

I copied the code and put it in code behind. How to include it correctly?

[Momerath]

That code works for winforms applications, not ASP.NET. To watermark on ASP you'll have to use javascript, if it's possible.

[AngelicOne]

I'm using it in winforms application.

[AngelicOne]

I've fixed it! Thanks!

[Momerath]

I've fixed it! Thanks!

Just wanted to say 'code behind' is an ASP.NET term :)