ColorDialog MyDialog = new ColorDialog();
// Keeps the user from selecting a custom color.
MyDialog.AllowFullOpen = false;
// Allows the user to get help. (The default is false.)
MyDialog.ShowHelp = true;
// Sets the initial color select to the current text color.
MyDialog.Color = textBox1.ForeColor;
// Update the text box color if the user clicks OK
if (MyDialog.ShowDialog() == DialogResult.OK)
textBox1.ForeColor = MyDialog.Color;