How to fill DataGridView Cells on cellvaluechanged in MYSQL

Question

I have a DataGridView in which there are 4 columns; Reference,Quantity, Rate and Amount.
The DataGridView is Editable. When I enter a value in the Reference Column then immediately it will fill the other values in the others cells from mysql database.

This is what I tried....

private void TAB_Credit_CellValueChanged(object sender, DataGridViewCellEventArgs e)
        {

            try
            {
                if (TAB_Credit.CurrentCell.ColumnIndex == 0)
                {

                    MySqlDataAdapter sa = new MySqlDataAdapter("SELECT * FROM table WHERE Reference='" + TAB_Credit.Rows[e.RowIndex].Cells["Reference"].Value + "'", MyConnexion);
                    DataTable dt2 = new DataTable();

                    sa.Fill(dt2);

                        double value = (double)TAB_Credit.Rows[e.RowIndex].Cells["Quantite"].Value * (double)TAB_Credit.Rows[e.RowIndex].Cells["PU"].Value;

                        TAB_Credit.Rows[e.RowIndex].Cells["Designation"].Value = dt2.Rows[0]["Designation"].ToString();
                        TAB_Credit.Rows[e.RowIndex].Cells["Quantite"].Value = dt2.Rows[0]["Quantite"].ToString();
                        TAB_Credit.Rows[e.RowIndex].Cells["PU"].Value = dt2.Rows[0]["Prix_Unitaire"].ToString();
                        TAB_Credit.Rows[e.RowIndex].Cells["Total"].Value = value.ToString();


                    }

            }
            catch
            { }
        }

So in the datagrid, when I insert in the Reference Cell nothing is appearing in the other cells.
Thank you.