Dropdown in Gridview should be filled on Selection of another Dropdown which is outside Gridview

Question

Hi friends i have a requirement where i have to fill a dropdown in a Gridview on Selection or IndexChange of another Dropdown Control which is not inside of any Gridview. i have done some code but i get the Null value; code is as below protected { void DrpProtocol_ID_SelectedIndexChanged( object sender EventArgs e) //DataRowView drv = e.Row.DataItem as DataRowView; dt = objDal.GetDataQry( { ddlCity = ( DataSet dt = new DataSet (); select InvId from dbo.InvDetails where ProtocolId=' + DrpProtocol_ID.SelectedItem.Text + '  Convert .ToString( ConfigurationManager .ConnectionStrings[ ConDMUtils_BackUp ].ConnectionString)); DropDownList ddlCity = new DropDownList (); foreach ( GridViewRow row in GridView1.Rows) DropDownList )row.FindControl( ddlSite ); //dropdown inside Gridview } { ddlCity.DataSource = dt.Tables[0]; if (ddlCity != null ) //ddlCity.DataTextField = InvId; ddlCity.DataValueField = InvId ; ddlCity.DataBind(); } } what is the mistake being done

Aamir Khan · Answer

Dear Santosh my query got solved i just called the FillGrid() Method in selection_indexchange() and passed the query in Gridview RowDataBound event.

Santhosh Kumar Jayaraman · Answer

please look into the attached solution..the mistake is there is a dropdown ddlsite in your gridview and ddlcity in your code You didnt map each other.

Santhosh Kumar Jayaraman · Answer

You have created ddlcity and did binding right?what is the purpose of it? where is that in your application (in aspx)?

Aamir Khan · Answer

pls make ur point clear not getting wht u have written

Santhosh Kumar Jayaraman · Answer

You created ddlcity as =new dropdownlist(). But thats not the dropdownlist in the gridview. You have to set this ddlcity as the dropdown inside gridview (i.e. ddlsite). Like this. DropDownList ddlCity = gridViewRow.FindControl( ddlSite ) as DropDownList;

Aamir Khan · Answer

Dear Santosh can u please elaborate the reply i am unable to get ur point... Thanks aamir

Santhosh Kumar Jayaraman · Answer

ddlcity =new DropDownList (); After that you didnt set that to ddlsite. try this after populating values to datatable dt write the below code foreach (GridViewRow gridViewRow in GridView1.Rows) { DropDownList ddlCity = gridViewRow.FindControl( ddlSite ) as DropDownList; ddlCity.DataSource = dt.Tables[0]; if (ddlCity != null ) //ddlCity.DataTextField = InvId; ddlCity.DataValueField = InvId ; ddlCity.DataBind(); }