regex - How to keep only specific item at Combobox

Question

I'm newbie here, and new to programing c#.

I am using Microsoft c#.

I want to know how to keep only specific item at Combobox when click on button1.

That item is a random word that was loaded automaticaly to the combobox1, but will contain "-test" word.

For example in this picture i just want to keep the list that contains "-test" word only in ouput combobox2 when click on button1.

To become like this

question from:https://stackoverflow.com/questions/65517150/how-to-keep-only-specific-item-at-combobox

Answer 1

i use this basic code but don't work

  private void button1_Click(object sender, EventArgs e)
    {




        var removeword = comboBox1.Items.Contains("test");
        if (comboBox1.Items.Contains("test") == true)
           
        }

            else
            {
            comboBox1.Items.Remove(removeword);
        }