the selectedindex and selectedvalue attributes are mutually exclusive exception?

See more:

C#

ASP.NET

 protected void ddlbranchdate_SelectedIndexChanged(object sender, EventArgs e)
   {
       try
       {
           DataTable dtgetvalues = new DataTable();
           //objRetailPL.date = Convert.ToDateTime(hdndate.Value);
           objRetailPL.branchdate = ddlbranchdate.SelectedItem.ToString();
           dtgetvalues = objRetailBAL.getbradisdate(objRetailPL);
           foreach(GridViewRow row in gvMeatDispatch.Rows)
           {
               DataTable dtpr = new DataTable();
               DropDownList ddl1 = (DropDownList)row.FindControl("ddlpartyname");
               objRetailPL.branch = dtgetvalues.Rows[0]["branch"].ToString();

               dtpr = objRetailBAL.getbran(objRetailPL);
               ddl1.DataSource = dtpr;
               ddl1.DataTextField = "partyname";
               ddl1.DataValueField = "sno";
               ddl1.DataBind();
               ddl1.Items.Add(new ListItem("--Select--", "0"));
              ddl1.SelectedIndex = ddl1.Items.Count - 1;
           }
       }
}

why i am getting this exception?..

i am using Dynamic Gridview and adding Rows Dynamically with the help of Button Control..

Outside i am declare another dropdown list ..if user selected some value from this Dropdownlist
then automatically bind the values to Dynamic Gridview ,Dropdown list values..


This is my Setprevious Data in Dynamic control Method..Here i called Dropdownlist selectedindexchanged event ..like..

private void SetPreviousData()
   {
       try
       {
           int rowIndex = 0;
           if (ViewState["CurrentTable"] != null)
           {
               DataTable dt = (DataTable)ViewState["CurrentTable"];
               if (dt.Rows.Count > 0)
               {
                   for (int i = 0; i < dt.Rows.Count; i++)
                   {
                       DropDownList ddlpname = (DropDownList)gvMeatDispatch.Rows[rowIndex].Cells[1].FindControl("ddlpartyname");
                       DropDownList ddlbt = (DropDownList)gvMeatDispatch.Rows[rowIndex].Cells[2].FindControl("ddlbirdtype");
                       TextBox txttotwt = (TextBox)gvMeatDispatch.Rows[rowIndex].Cells[3].FindControl("txttotwt");
                       TextBox txttransbirds1 = (TextBox)gvMeatDispatch.Rows[rowIndex].Cells[4].FindControl("txtrateforkg");
                       TextBox txtmort1 = (TextBox)gvMeatDispatch.Rows[rowIndex].Cells[5].FindControl("txtdcno");

                      // Dropdownlist selectedIndex Changed event

                       ddlbranchdate_SelectedIndexChanged(null, null);

                       ddlpname.SelectedValue = dt.Rows[i]["Col1"].ToString();
                       ddlbt.SelectedValue = dt.Rows[i]["Col2"].ToString();
                       txttotwt.Text = dt.Rows[i]["col3"].ToString();
                       txttransbirds1.Text = dt.Rows[i]["Col4"].ToString();
                       txtmort1.Text = dt.Rows[i]["Col5"].ToString();

                       rowIndex++;
                   }
               }
           }
       }

please help me...