Do not allow twice values into a textbox

Question

Hi!

 

I have one combobox with a textbox.

Inside of my combobox I have three items (Morning, afternoon, goodnight). Then each selection is displayed into the textBox.

What I need to do?

When I select "morning" for example I would like that even I selected the second way its not should appear twice into the textbox (only once). Its allow to  appear again ONLY when the textbox its clean it.

 

My code:

 

private void cbxChoice_SelectedIndexChanged(object sender, EventArgs e)

{

switch (cbxChoice.SelectedIndex)

{

case 0:

//Morning

textDisplay.Text += "\n" + Environment.NewLine + cbxChoice.Text + Environment.NewLine + ",";

textDisplay.clear();

break;

 

case 1:

//Afternoon

textDisplay.Text += "\n" + Environment.NewLine + cbxChoice.Text + Environment.NewLine + ",";

textDisplay.clear();

break;

 

case 2:

//Night

textDisplay.Text += "\n" + Environment.NewLine + cbxChoice.Text + Environment.NewLine + ",";

textDisplay.clear();

break;