cannot bind data to gridview combobox in datagridview at editing mode

Question

The following is my code for row editing event.

protected void branchgrid_RowEditing(object sender, GridViewEditEventArgs e)
        {
            if (TextBox1.Text == "")
        {
            workingdaygrid.EditIndex = e.NewEditIndex;
            bindworkingday();

            GridViewRow row = workingdaygrid.Rows[e.NewEditIndex];
            DropDownList dl = row.FindControl("Workingdaytype") as DropDownList;
            DataTable worktype = inter.bindworkdaytype();
            dl.DataSource = worktype;
            dl.DataTextField = "Workingday_type";
            dl.DataValueField = "Time_id";
            dl.DataBind();
        }
        else
        {
            string datetime = TextBox1.Text;
            comp.DATETIME = Convert.ToDateTime(datetime);
            DataTable result = inter.searchworkday(comp);
            workingdaygrid.DataSource = result;
            workingdaygrid.DataBind();

            workingdaygrid.EditIndex = e.NewEditIndex;
            GridViewRow row = workingdaygrid.Rows[e.NewEditIndex];
            DropDownList dl = row.FindControl("Workingdaytype") as DropDownList;
            DataTable worktype = inter.bindworkdaytype();
            //string datetime = TextBox1.Text;
            dl.DataSource = worktype;
            dl.DataTextField = "Workingday_type";
            dl.DataValueField = "Time_id";
            dl.DataBind();
        }

after filtration using search button, I am trying editing the particular row(data) but i cannot get the gridview combobox value. it is blank. but in the full databind(first if condition) combobox value is binded.

my seach button code is

string datetime = TextBox1.Text;
            comp.DATETIME = Convert.ToDateTime(datetime);

            DataTable result = inter.searchworkday(comp);
            workingdaygrid.DataSource = result;
            workingdaygrid.DataBind();