Question

I have RichTextBox control with some BASIC TEXT entered. I wish to customize it in a way that, when user will enter or paste some text this would have different font color than the BASIC TEXT.

i was changing SelectionBackColor prperty on KeyDown event, but it occurs also when user tries only to copy part of BASIC TEXT.

 private void richTextBox1_KeyDown(object sender, KeyEventArgs e)
    {
        RichTextBox richTextBox1 = sender as RichTextBox;
        richTextBox1.SelectionBackColor = Color.LightCoral;
    }

Answer 1

Instead of KeyDown, use TextChanged event:

private void richTextBox1_TextChanged(object sender, EventArgs e)
{
    RichTextBox richTextBox1 = sender as RichTextBox;
    richTextBox1.SelectionBackColor = Color.LightCoral;
}