Change the borderColor of the TextBox

Question

How can I change the BorderColor of the Textbox when a user Clicks on it or focuses on it?

Answer 1

try this

bool focus = false;
private void Form1_Paint(object sender, PaintEventArgs e)
{
    if (focus)
    {
        textBox1.BorderStyle = BorderStyle.None;
        Pen p = new Pen(Color.Red);
        Graphics g = e.Graphics;
        int variance = 3;
        g.DrawRectangle(p, new Rectangle(textBox1.Location.X - variance, textBox1.Location.Y - variance, textBox1.Width + variance, textBox1.Height +variance ));
    }
    else
    {
        textBox1.BorderStyle = BorderStyle.FixedSingle;
    }
}

private void textBox1_Enter(object sender, EventArgs e)
{
    focus = true;
    this.Refresh();
}

private void textBox1_Leave(object sender, EventArgs e)
{
    focus = false;
    this.Refresh();
}