Collect user input from form and change it to upper or lower case in C#

In this example I have a text box on my windows form to collect the user input and a label to display the outcome once a button is pressed. The code is as follows to change the input to upper and lower case.

private void button3_Click(object sender, EventArgs e)

{

label1.Text = textBox.Text.ToUpper();

}

or

{

label1.Text = textBox.Text.ToLower();

}