C# Datarepeater check Textbox Value

Question

I have a C# Datarepeator on my Form1 and I bind it dynamically with Binding Source. and everything is fine by displaying the data.
Now I have to check an textbox value for each item in the repeater using if statement and if true then I should write a value in a label control on the same item of the repeater.

My code is as following:

private void btn_search_DE_Click(object sender, EventArgs e)
{
    txt_tech_approval.DataBindings.Clear();
    txt_tech_approval.DataBindings.Add("Text", bSource, "Username", false, 
                                        DataSourceUpdateMode.OnPropertyChanged);

   switch (txt_tech_approval.Text)
   {
        case "CE":
            lbl_CE.Text = "X";
            break;
    }   
}

how can i solve it?

thanks alot .