Toggle text color in C#

You can use a timer drop it in your form, and you do a modulo on 3 and if the color nlack chage it to red otherwise black

timer_Tick()
{
if((DateTime.Now.Second % 3) ==0)
{
if(textBox.BackColor == Color.Black)
textBox.BackColor == Color.Red;
else
textBox.BackColor == Color.Black;
}
}

In C# WinForms...

        private System.Windows.Forms.Timer tmr;

        private void Form1_Load(object sender, EventArgs e)
        {
            label1.ForeColor = Color.Red;
            label1.Tag = Color.Black;

            tmr = new System.Windows.Forms.Timer();
            tmr.Interval = 3000;
            tmr.Tick += new EventHandler(tmr_Tick);
            tmr.Start();
        }

        void tmr_Tick(object sender, EventArgs e)
        {
            Color tmp = label1.ForeColor;
            label1.ForeColor = (Color)label1.Tag;
            label1.Tag = tmp;
        }

how do I make it to stop after it has toggled couple of times?

timer.Enbled = false;