C#如何允许我的textbox.text接受多个数字

private void textBox1_TextChanged(object sender, EventArgs e)
{
    Regex regex = new Regex("^[0-9]+$");
    if (!regex.IsMatch(textBox1.Text))
    {
        textBox1.Text = "";
        MessageBox.Show("请输入数字！");
    }
}

private void textBox1_KeyPress(object sender, KeyPressEventArgs e)
{
    if (!char.IsControl(e.KeyChar) && !char.IsDigit(e.KeyChar))
    {
        e.Handled = true;
        MessageBox.Show("请输入数字！");
    }
}

private void textBox1_KeyDown(object sender, KeyEventArgs e)
{
    if (e.KeyCode < Keys.D0 || e.KeyCode > Keys.D9)
    {
        e.SuppressKeyPress = true;
        MessageBox.Show("请输入数字！");
    }
}