How to get selected row cell value in 'RowCommand'?

I got what I seek from this link

http://www.aspdotnet-suresh.com/2012/06/get-multiple-datakeyname-values-from.html

but getting an error at 'string value1 = gvUserInfo.DataKeys[gvrow.RowIndex].Values[0].ToString();' /*at underlined*/

here iam getting complaint Id and sending it to another page like this same on one link button need to get two col values i.e, ComolaintId and UserId.


                       
                           
                                <%--CommandArgument='<%#Eval("ComplaintId")%>'--%>
                           
                           
                               
                           
                       


protected void gridComplaintSearch_RowCommand(object sender, GridViewCommandEventArgs e)
        {
            if (e.CommandName == "CompVIEW")
            {
                int row = Convert.ToInt32(e.CommandArgument);
                Session["compUid"] = row;
               
                Response.Write("");
                Response.Write("");
            }
}

visit following links to help
http://www.aspsnippets.com/Articles/How-to-get-Selected-Row-cell-value-from-GridView-in-ASPNet.aspx
http://www.aspdotnet-suresh.com/2014/11/get-selected-row-cell-value-from-gridview-csharp-vbnet.html

http://www.dotnetfunda.com/articles/show/442/how-to-get-the-values-of-selected-row-from-a-gridview-using-aspnet
http://asp.net-informations.com/gridview/select-row.htm

didnt get your mean

I want another cell value,which I gave in DataKeyNames is complaint id which I alredy retrieve.

this will return value you set in DataKeyNames in gridview

show your aspx gridview code html
May be cell[4] has no value


also try this way
if (e.CommandName == "CompVIEW")
{
int row = Convert.ToInt32(e.CommandArgument);
 Control ctrl = e.CommandSource as Control;
                GridViewRow CurrentRow = ctrl.NamingContainer as GridViewRow;
                int custId = grdSearch.DataKeys[CurrentRow.RowIndex].Value.ToString();

and

in gridview
  DataKeyNames="ID"  where id will be your complaintid