How to change the font color of a disabled TextBox?

NOTE: see Cheetah's answer below as it identifies a prerequisite to get this solution to work. Setting the BackColor of the TextBox.

I think what you really want to do is enable the TextBox and set the ReadOnly property to true.

It's a bit tricky to change the color of the text in a disabled TextBox. I think you'd probably have to subclass and override the OnPaint event.

ReadOnly though should give you the same result as !Enabled and allow you to maintain control of the color and formatting of the TextBox. I think it will also still support selecting and copying text from the TextBox which is not possible with a disabled TextBox.

Another simple alternative is to use a Label instead of a TextBox.

Additionally, in order for ForeColor to be obeyed on a TextBox marked ReadOnly, you must explicitly set the BackColor. If you want to have it still use the default BackColor, you have to make the set explicit, as the designer is too smart for its own good here. It is sufficient to set the BackColor to its current value. I do this in the Load event for the form, like so:

private void FormFoo_Load(...) {
    txtFoo.BackColor = txtFoo.BackColor;
}

I've just found a great way of doing that. In my example I'm using a RichTextBox but it should work with any Control:

public class DisabledRichTextBox : System.Windows.Forms.RichTextBox
{
    // See: http://wiki.winehq.org/List_Of_Windows_Messages

    private const int WM_SETFOCUS   = 0x07;
    private const int WM_ENABLE     = 0x0A;
    private const int WM_SETCURSOR  = 0x20;

    protected override void WndProc(ref System.Windows.Forms.Message m)
    {
        if (!(m.Msg == WM_SETFOCUS || m.Msg == WM_ENABLE || m.Msg == WM_SETCURSOR))
            base.WndProc(ref m);
    }
}

You can safely set Enabled = true and ReadOnly = false, and it will act like a label, preventing focus, user input, cursor change, without being actually disabled.

See if it works for you. Greetings