[Solved] Text in comBobox

[chan]

HI
There are a couple of comBobox named comBobox1 and comBobox2, and there is a SelectIndexChanged event for comBobox1.when this event fired,value (text as well) in  comBobox2 shloud be changed as value in comBobox1 was changed. Here i get a problem,when the event occured,text in comBobox2 always the old one(even if it did not exist in the new datasourse),it did not refresh, and i need to delete the old text manually.
Is there any way to resolve it? Following is the demo

 protected void ddlMfg_SelectedIndexChanged(object sender, EventArgs e)
    {
        int mfg;
        if (int.TryParse(this.ddlMfg.SelectedValue, out mfg))
        {
            this.ddlBrandedLabel.Items.Clear();
            this.ddlBrandedLabel.DataSource = ProductStatus.ProductBrandedLabel_SelectAll_ByMfgId_AsDataSet(mfg, 0, 9);
            this.ddlBrandedLabel.DataBind();
        }
        else
        {
            ddlBrandedLabel.Items.Clear();
        }
    }

Best regards