c# - GridView RowIndex is 0 -

i have gridview on page , click on edit, displays editable text box when edit value , press update errors:

the error suggests gridview2.datakeys null.

i adding debugging by:

int test = e.rowindex

and gives me value of 0

my code below:

can suggest why im getting:

an exception of type 'system.argumentoutofrangeexception' occurred in mscorlib.dll not handled in user code

additional information: index out of range. must non-negative , less size of collection.

protected void gridview2_rowupdating(object sender, gridviewupdateeventargs e)  {     int datakeyvalue = convert.toint32(gridview2.datakeys[e.rowindex].value.tostring());     gridviewrow row = (gridviewrow)gridview2.rows[e.rowindex];     label lblid = (label)row.findcontrol("lblid");      textbox gvtxtnextstep = (textbox)row.cells[0].controls[0];      gridview2.editindex = -1;      cobj.supportref1 = txtsupportref.text;     cobj.nextstep1 = txtnextstep.text;       bobj.microticketupdate(cobj);      gridview2.databind();  } 

you need set datakeynames property on gridview control relevant id property e.g. <asp:gridview datakeynames="personid"...

edit

below complete example return valid primary key value in datakeyvalue variable.you can copy example, is, new web page in web application , test see how works , how data get's bound , hope looking @ example can figure out changes should make code working:

.aspx:

<asp:gridview      datakeynames="id"      id="gridview1"      runat="server"      autogeneratecolumns="false"      autogenerateeditbutton="true"      onrowediting="gridview1_rowediting"      onrowupdating="gridview1_rowupdating" onrowcancelingedit="gridview1_rowcancelingedit">     <columns>         <asp:boundfield datafield="name" headertext="name" />         <asp:boundfield datafield="creditrequest" headertext="credit request" />     </columns> </asp:gridview> 

code behind:

 public class persont     {         public int id { get; set; }         public string name { get; set; }         public string creditrequest { get; set; }     }      public partial class aaaa_gridviewrowupdating : system.web.ui.page     {         protected void page_load(object sender, eventargs e)         {             if (!page.ispostback)             {                 this.binddata();             }         }          private void binddata()         {             var p1 = new persont() { id = 10, name = "person 1", creditrequest = "credit request 1" };             var p2 = new persont() { id = 20, name = "person 2", creditrequest = "credit request 2" };              var list = new list<persont> { p1, p2 };             gridview1.datasource = list;             gridview1.databind();         }          protected void gridview1_rowediting(object sender, gridviewediteventargs e)         {             gridview1.editindex = e.neweditindex;             binddata();         }          protected void gridview1_rowupdating(object sender, gridviewupdateeventargs e)         {             system.diagnostics.debugger.break();             int index = e.rowindex;             int datakeyvalue = convert.toint32(gridview1.datakeys[index].value.tostring());         }          protected void gridview1_rowcancelingedit(object sender, gridviewcancelediteventargs e)         {             gridview1.editindex = -1;             binddata();         }     }