on click of row event of grid you can add code like this to create a textxbox.
protected void grd_RowEditing(object sender, GridViewEditEventArgs e)
{
GridViewRow selectRow = grd.Rows(e.NewEditIndex);
TextBox txtKj=(TextBox)selectRow.Cells[3].FindControl("txtKjId");
}
Hope this help.
-SG