c# - Invalid postback or callback argument error when button click - Beginner -

i getting following error;

invalid postback or callback argument. event validation enabled using in configuration or <%@ page enableeventvalidation="true" %> in page. security purposes, feature verifies arguments postback or callback events originate server control rendered them. if data valid , expected, use clientscriptmanager.registerforeventvalidation method in order register postback or callback data validation.

i added columm, , added button it, when button fired following c# code gets executed;

asp.net code

    <columns>         <%-- <asp:boundfield /> definitions here --%>         <asp:templatefield>   <itemtemplate>     <asp:button id="addbutton" runat="server"        commandname="addtocart"        commandargument="<%# ((gridviewrow) container).rowindex %>"       text="add cart" />   </itemtemplate>  </asp:templatefield>      </columns> 

c#

   protected void gridview1_rowcommand(object sender,gridviewcommandeventargs e)         {             if (e.commandname == "addtocart")             {                 int index = convert.toint32(e.commandargument);                  // retrieve row contains button                  // rows collection.                 gridviewrow row = gridview1.rows[index];              }          } 

how rid of error;

i added <globalization requestencoding="utf-8"/> error still there. `

update

            <asp:gridview runat="server" id="gdv" autogeneratecolumns="true" onsorting="sortrecord" allowsorting="true" datakeynames="hotelname" cellpadding="4" width="746px">     <columns>         <%-- <asp:boundfield /> definitions here --%>         <asp:templatefield>   <itemtemplate>     <asp:button id="addbutton" runat="server"        commandname="addtocart"        commandargument="<%# ((gridviewrow) container).rowindex %>"       text="add cart" />   </itemtemplate>  </asp:templatefield>      </columns> </asp:gridview> 

what find myself using buttons onclick events instead of gridviewrowcommand. it's easier work part. asp like;

<asp:gridview runat="server" id="gdv" autogeneratecolumns="false" onsorting="sortrecord"    allowsorting="true" datakeynames="hotelname" cellpadding="4" width="746px">     <columns>       <%-- <asp:boundfield /> definitions here --%>         <asp:templatefield>            <itemtemplate>               <asp:button id="addbutton" runat="server" onclick="addbutton_click" text="add cart" />            </itemtemplate>          </asp:templatefield>     </columns> </asp:gridview> 

and c# like;

protected void addbutton_click(object sender, eventargs e) {     button btn = (button)sender;     gridviewrow row = (gridviewrow)btn.namingcontainer; } 

now in code behind can need row, , know you'll getting row want.

hope helps!