How to append all data of Repeater Items in String and then to a TextBox in ASP.Net

Refer

foreach (RepeaterItem item in Repeater1.Items)
{
   this.txtCustomerName.Text += (item.FindControl("lblName") as Label).Text + ",";
}

this.txtCustomerName.Text = this.txtCustomerName.Text.Remove(this.txtCustomerName.Text.LastIndexOf(",") - 1);