GridView控件编辑状态下的DropDownList控件选中原值

如果DropDownList控件的数据源可以直接调用某个方法就能绑定的话，可以在HTML中对DropDownList进行原值定位
 HTML：

< asp:TemplateField  HeaderText ="专业" >
   < EditItemTemplate >
     < asp:DropDownList  id ="ddlMajorBind"  runat ="server"  DataTextField ="MajorName"  DataValueField ="MajorID"  DataSource ="<%#bindMajor() %>"  SelectedValue ='<%#  Bind("MajorID") % > '> </ asp:DropDownList >  
   </ EditItemTemplate >
   < ItemTemplate >
     < asp:Label  id ="Label3"  runat ="server"  Text ='<%#  Bind("MajorName") % > '> </ asp:Label >    
   </ ItemTemplate >
   < ItemStyle  HorizontalAlign ="Center"   />
</ asp:TemplateField >

C#：

public  DataSet bindMajor()
    {
         return   new  MajorBLL().SelectTheMajorByDeptID(Session[ " DeptID " ].ToString());
    }

如果DropDownList控件的数据源不能直接调用某个方法绑定，必须在RowDataBind事件中进行绑定的话，原值定位也需要在此事件中完成

  if  (e.Row.RowType  ==  DataControlRowType.DataRow)
        {
             // GridView控件的编辑状态下下拉列表选中原值

             if  (e.Row.FindControl( " ddlMajorBind " )  !=   null   &&  e.Row.FindControl( " ddlDirectionBind " )  !=   null )
            {
                DropDownList ddlMajor  =  (DropDownList)e.Row.FindControl( " ddlMajorBind " );
                DropDownList ddlDirection  =  (DropDownList)e.Row.FindControl( " ddlDirectionBind " );
                ddlDirection.DataSource  =  bindDirection(ddlMajor.SelectedValue);
                ddlDirection.DataTextField  =   " DirectionName " ;
                ddlDirection.DataValueField  =   " DirectionId " ;
                ddlDirection.DataBind();
                ddlDirection.Items.Insert( 0 ,  new  ListItem( " 无 " ,  "" ));
                ddlDirection.SelectedValue  =  DataBinder.Eval(e.Row.DataItem,  " DirectionID " ).ToString();//原值定位
            }
        } 
    }