asp.net - Error in export gridview to excel -

i tring export gridview excel.for wrote code in content page.but got error.when writting attribute[runat]="server";so searched on net wrote this.

public override void verifyrenderinginserverform(control control)  { /* confirms htmlform control rendered specified asp.net server control @ run time. */  }  

.but remove code page.but when running page display on login page.i want remove sentence coming @ run time.

i have 1 master page , remaining content page.the login page not content page, simple aspx page.in master page there form tag.in 1 of content page,i added code export gridview.

htmlform frm = new htmlform();  frm.attributes["runat"] = "server"; 

so got error.i searched on net error ,ppl saying use method ,so wrote method.

public override void verifyrenderinginserverform(control control)  { /* confirms htmlform control rendered specified asp.net server control @ run time. */  }  

but problem when running project code display on login page not remaing content page.so removed code , override method, still code printed on login page.i looked login page finding out method defined there.but there no such method in login page.what should do?how remove that.