How to add an new item to a combobox which will bound to database

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C#

WinForms

hi hi

in my application i am using table called teacherdetailloading which will to bound combobox

here is my piece of code:

    combobox2.DataSource = ds.Tables["teacherdetailloading"];//ds is dataset
combobox2.DisplayMember = "name";
combobox2.ValueMember = "name";

if i try to add new item called select to that combobox it will display an error message.

Item collection cannont be modified when the datasource is set.

i have tried this concepts

//DataTable Dt1 = new DataTable();
             //Dt1.Columns.Add("district");
             //Dt1.Rows.Add("select");
             //Dt1.Merge(ds.Tables["teacherdetailloading"]);

             combobox2.DataSource = ds.Tables["Dt1"];
             combobox2.DisplayMember = "district";
             combobox2.ValueMember = "district";

but it will not work. if anyone have any other way of doing it help me.

thanks in advance.