c# - Data source is an invalid type. It must be either an IListSource, IEnumerable, or IDataSource -

i have function dropdownlist , should run store procedure , supplires names taht should displayes @ dropdownlsit .

this function :

public void loadsuppliers(dropdownlist ddl , int num) {     con = connect("igroup9_test1connectionstring");     using (sqlcommand sqlcomm = new sqlcommand("[spgetsuppliers]", con))     {         if (con.state != connectionstate.open)         {             con.open();         }          try         {             sqlcomm.commandtype = commandtype.storedprocedure;             sqlcomm.parameters.addwithvalue("@rowmeterialid ", num);              sqlcomm.commandtimeout = 600;             ddl.datasource = sqlcomm;             sqlcomm.executenonquery();             ddl.databind();             ddl.datatextfield = "sname";             ddl.datavaluefield = "sname";         }          catch (exception ex)         {             throw (ex);         }     }  } 

and procedure:

use [igroup9_test1] go /****** object:  storedprocedure [dbo].[spgetsuppliers]    script date: 03/24/2014 18:13:12 ******/ set ansi_nulls on go set quoted_identifier on go alter proc [dbo].[spgetsuppliers] ( @rowmeterialid int )   begin  select distinct sname supplier, rawmaterials, supplierrawmaterials rawmaterials.rmid=@rowmeterialid , rawmaterials.rmid=supplierrawmaterials.rmid , supplierrawmaterials.supplierid=supplier.supplierid  end 

when i'm running program throw error:

system.invalidoperationexception: data source invalid type. must either ilistsource, ienumerable, or idatasource.

you cannot assign ddl.datasource = sqlcomm since sqlcommand.

fill dataset , assign

ddl.datasource = dsmyresult;