كيفية كتابت ارقم فقط في Text

//Event
        private void textBox1_KeyPress(object sender, KeyPressEventArgs e)
        {
            TextNumber= textBox1.Text;
        }
          //Event
        private void textBox1_TextChanged(object sender, EventArgs e)
        {


            try
            { 

                Convert.ToInt32(textBox1.Text);

            }

            catch (Exception ex)
            {


                MessageBox.Show("PIZ write to Number");

                textBox1.Text = TextNumber;

            }

ring TextNumber;