i have a problem with this error(this error related edit and
delete button,when i click this button in datagrid..i will
get this error)"Invalid postback or callback argument.
Event validation is enabled using <pages
enableEventValidation="true"/> in configuration or <%@ Page
EnableEventValidation="true" %> in a page. For security
purposes, this feature verifies that arguments to postback
or callback events originate from the server control that
originally rendered them. If the data is valid and
expected, use the
ClientScriptManager.RegisterForEventValidation method in
order to register the postback or callback data for validation."

this is my code :
<%@ Page Language="VB" Debug="false" %>
<%@ import Namespace="Sytem.Data" %>
<%@ import Namespace="System.Data.OleDB" %>
<script runat="server">

Sub Page_Load(Src As Object, E As EventArgs)
Dim ds As new System.Data.Dataset
Dim dbconnection as System.Data.OleDb.OleDbConnection
try
Dim WhereIsTheDatabase as String =
System.Web.HttpContext.Current.Server.mappath("./LeaveDB.mdb")

Dim dbstr as String= "Provider=Microsoft.Jet.OLEDB.4.0; Data
Source="&WhereIsTheDatabase &";User ID=admin ;Password="
dbconnection=New
System.Data.OleDb.OleDbConnection(dbstr)

Dim dbcommand As New System.Data.OleDb.OleDbCommand
Dim da As New System.Data.OleDb.OleDbDataAdapter

dbconnection.Open()
dbcommand.CommandText="SELECT * FROM Leave Order By Leave_ID"
dbcommand.Connection=dbconnection
da.SelectCommand=dbcommand
da.Fill(ds)

Catch Ex as Exception
throw new Exception("Error detection"
&Ex.Message)
finally
dbconnection.Close()
End Try

dtgridLeaveList.DataSource=ds
dtgridLeaveList.DataBind()


if ds.Tables.count > 0 then
Dim dt as System.Data.DataTable =
ds.Tables(0)
dtgridLeaveList.DataBind()
else
MyJSLabel.text = "<script>window.alert('No Record in the
Access file.')</"&"script>"
End if


End Sub






Sub UpdateList(Byval Source As Object,Byval e as
DataGridCommandEventArgs)
If e.CommandName="Edit" Then
Dim LeaveID as
Integer=CInt(val(CType(e.Item.FindControl("lblLeaveID"),
Label).Text))
Dim DateApplied As
String=CType(e.Item.FindControl("lblDateApplied"), Label).Text
Dim ICNO as String = CType(e.Item.FindControl("lblICNO"),
Label).Text
Dim DaysMax as Integer=
CInt(val(CType(e.Item.FindControl("lblDaysMax"), Label).Text))
Dim LeaveStart As
Date=CDate(CType(e.Item.FindControl("lblLeaveStart"),
Label).Text)
Dim LeaveEnd As Date=
CDate(CType(e.Item.FindControl("lblLeaveEnd"), Label).Text)
Dim TypeofLeave As
String=CType(e.Item.FindControl("lblTypeOfLeave"), Label).Text
Dim Reason As String=Ctype(e.Item.FindControl("lblReason"),
Label).Text
Dim NoOfDays as
Integer=CInt(val(CType(e.Item.FindControl("lblNoOfDays"),
Label).Text))
Dim BalanceAnnualLeaveCF as
String=CType(e.Item.FindControl("lblBalanceAnnualLeaveCF"),
Label).Text

Dim BalanceAnnualLeaveBF as
Integer=CInt(val(CType(e.Item.FindControl("lblBalanceAnnualLeaveBF"),
Label).Text))

Dim AnnualLeaveEntitle As Integer=
CInt(val(CType(e.Item.FindControl("lblAnnualLeaveEntitle"),
Label).Text))

Dim TotalAnnualLeave as
Integer=CInt(val(CType(e.Item.FindControl("lblTotalAnnualLeave"),
Label).Text))

Dim LessAnnualLeaveTaken as
Integer=CInt(val(CType(e.Item.FindControl("lblLessAnnualLeaveTaken"),
Label).Text))

Dim BalanceAnnualLeave as
Integer=CInt(val(CType(e.Item.FindControl("lblBalanceAnnualLeave"),
Label).Text))

Dim str as String="LeaveID=" &LeaveID.ToString
&"&DateApplied=" &DateApplied &"&ICNO=" &ICNO &"&DaysMax="
&DaysMax &"&LeaveStart=" &LeaveStart & "&LeaveEnd="
&LeaveEnd & "&TypeofLeave=" &TypeofLeave & "&Reason="
&Reason & "&NoOfDays=" &NoOfDays & "&BalanceAnnualLeaveCF="
&BalanceAnnualLeaveCF & "&BalanceAnnualLeaveBF="
&BalanceAnnualLeaveBF & "&AnnualLeaveEntitle="
&AnnualLeaveEntitle & "&TotalAnnualLeave=" &TotalAnnualLeave
& "&LessAnnualLeaveTaken=" &LessAnnualLeaveTaken &
"&BalanceAnnualLeave=" &BalanceAnnualLeave

Response.Redirect("Leave Info.aspx?" &str)

End If


End Sub







Sub OnDelete(Byval sender as Object, Byval e as
DataGridCommandEventArgs)
If e.CommandName="Delete" Then
Dim ds As new System.Data.Dataset
Dim dbconnection as System.Data.OleDb.OleDbConnection
Dim WhereIsTheDatabase as String =
System.Web.HttpContext.Current.Server.mappath("./LeaveDB.mdb")
Dim dbstr as String= "Provider=Microsoft.Jet.OLEDB.4.0; Data
Source="&WhereIsTheDatabase &";User ID=admin ;Password="
dbconnection=New System.Data.OleDb.OleDbConnection(dbstr)

Dim dbcommand As New System.Data.OleDb.OleDbCommand
Dim da As New System.Data.OleDb.OleDbDataAdapter

dbconnection.Open()

dbCommand.CommandText="DELETE FROM Leave WHERE
Leave_ID=" &e.Item.Cells(1).Text
dbCommand.ExecuteNonQuery


dbcommand.CommandText="SELECT * FROM Leave Order By
Leave_ID"
dbcommand.Connection=dbconnection
da.SelectCommand=dbcommand
da.Fill(ds)

dbconnection.Close()

dtgridLeaveList.DataSource=ds
dtgridLeaveList.DataBind()
End If
End Sub

</script>


















<html>
<head>
</head>
<body>
<form runat="server">
<font face="Arial Narrow" size="4">(Search Based On
Staff I.C No)</font>
<font face="Arial Narrow"></font>
<font face="Arial Narrow><font size="4">IC.No</font> </font>

<asp:TextBox id="TextBox1" runat="server"
Width="264px"></asp:TextBox>
<font face="Arial Narrow"> </font>
<asp:Button id="Button1" runat="server"
Text="Search"></asp:Button>
(XXXXXX-XX-XXXX)
<font face="Arial Narrow">&nbsp;</font>
<asp:DataGrid id="dtgridLeaveList" runat="server"
OnEditCommand="UpdateList" OnDeleteCommand="OnDelete"
AutoGenerateColumns="False" Font-Size="Medium"
Font-Names="Arial Narrow">

<SelectedItemStyle backcolor="Blue" font-bold="False"
font-italic="False" font-overline="False"
font-strikeout="False"
font-underline="False"></SelectedItemStyle>

<Columns>
<asp:TemplateColumn HeaderText="Leave ID" Visible="False">
<ItemTemplate>
<asp:Label id="lblLeaveID" text='<%#
DataBinder.Eval(Container.DataItem,"Leave_ID") %>'
runat="server"></asp:Label>
</ItemTemplate>
</asp:TemplateColumn>

<asp:TemplateColumn HeaderText="Date Applied">
<ItemTemplate>
<asp:Label id="lblDateApplied"
text='<%#DataBinder.Eval(Container.DataItem,"DateLeaveApplied")
%>' runat="server"></asp:Label>
</ItemTemplate>
<HeaderStyle backcolor="White" font-bold="False"
font-italic="False" font-overline="False"
font-strikeout="False" font-underline="False"></HeaderStyle>
<ItemStyle backcolor="White" font-bold="False"
font-italic="False" font-overline="False"
font-strikeout="False" font-underline="False"></ItemStyle>
</asp:TemplateColumn>

<asp:TemplateColumn HeaderText="I.C No">
<ItemTemplate>
<asp:Label id="lblICNO" text='<%#
DataBinder.Eval(Container.DataItem,"ICNo") %>'
runat="server"></asp:Label>
</ItemTemplate>
</asp:TemplateColumn>




<asp:TemplateColumn HeaderText="Days Max">
<ItemTemplate>
<asp:Label id="lblDaysMax" text='<%#
DataBinder.Eval(Container.DataItem,"AnnualLeaveEntitle") %>'
runat="server"></asp:Label>
</ItemTemplate>
</asp:TemplateColumn>

<asp:TemplateColumn HeaderText="Leave Start">
<ItemTemplate>
<asp:Label id="lblLeaveStart" text='<%#
DataBinder.Eval(Container.DataItem,"Leave_Start") %>'
runat="server"></asp:Label>
</ItemTemplate>
</asp:TemplateColumn>

<asp:TemplateColumn HeaderText="Leave End">
<ItemTemplate>
<asp:Label id="lblLeaveEnd" text='<%#
DataBinder.Eval(Container.DataItem,"Leave_End") %>'
runat="server"></asp:Label>
</ItemTemplate>
</asp:TemplateColumn>

<asp:TemplateColumn HeaderText="Type of Leave">
<ItemTemplate>
<asp:Label id="lblTypeOfLeave" text='<%#
DataBinder.Eval(Container.DataItem,"TypeOfLeave") %>'
runat="server"></asp:Label>
</ItemTemplate>
</asp:TemplateColumn>

<asp:TemplateColumn HeaderText="Reason">
<ItemTemplate>
<asp:Label id="lblReason" text='<%#
DataBinder.Eval(Container.DataItem,"Reason") %>'
runat="server"></asp:Label>
</ItemTemplate>
</asp:TemplateColumn>

<asp:TemplateColumn HeaderText="No of Days">
<ItemTemplate>
<asp:Label id="lblNoOfDays" text='<%#
DataBinder.Eval(Container.DataItem,"NoOfDays") %>'
runat="server"></asp:Label>
</ItemTemplate>
</asp:TemplateColumn>

<asp:TemplateColumn HeaderText="Balance Annual Leave C/F">
<ItemTemplate>
<asp:Label id="lblBalanceAnnualLeaveCF" text='<%#
DataBinder.Eval(Container.DataItem,"Remarks") %>'
runat="server"></asp:Label>
</ItemTemplate>
<HeaderStyle backcolor="LightGray" font-bold="False"
font-italic="False" font-overline="False"
font-strikeout="False" font-underline="False"></HeaderStyle>
<ItemStyle backcolor="Yellow" font-bold="False"
font-italic="False" font-overline="False"
font-strikeout="False" font-underline="False"></ItemStyle>
</asp:TemplateColumn>

<asp:TemplateColumn HeaderText="Balance Annual Leave B/F">
<ItemTemplate>
<asp:Label id="lblBalanceAnnualLeaveBF" text='<%#
DataBinder.Eval(Container.DataItem,"BalanceAnnualLeaveBF")
%>' runat="server"></asp:Label>
</ItemTemplate>
<HeaderStyle backcolor="LightGray" font-bold="False"
font-italic="False" font-overline="False"
font-strikeout="False" font-underline="False"></HeaderStyle>
<ItemStyle backcolor="Yellow" font-bold="False"
font-italic="False" font-overline="False"
font-strikeout="False" font-underline="False"></ItemStyle>
</asp:TemplateColumn>

<asp:TemplateColumn HeaderText="Annual Leave Entitle">
<ItemTemplate>
<asp:Label id="lblAnnualLeaveEntitle" text='<%#
DataBinder.Eval(Container.DataItem,"AnnualLeaveEntitle") %>'
runat="server"></asp:Label>
</ItemTemplate>
<HeaderStyle backcolor="LightGray" font-bold="False"
font-italic="False" font-overline="False"
font-strikeout="False" font-underline="False"></HeaderStyle>
<ItemStyle backcolor="Yellow" font-bold="False"
font-italic="False" font-overline="False"
font-strikeout="False" font-underline="False"></ItemStyle>
</asp:TemplateColumn>

<asp:TemplateColumn HeaderText="Total Annual Leave">
<ItemTemplate>
<asp:Label id="lblTotalAnnualLeave" text='<%#
DataBinder.Eval(Container.DataItem,"TotalAnnualLeave") %>'
runat="server"></asp:Label>
</ItemTemplate>
</asp:TemplateColumn>

<asp:TemplateColumn HeaderText="Less Annual Leave Taken">
<ItemTemplate>
<asp:Label id="lblLessAnnualLeaveTaken" text='<%#
DataBinder.Eval(Container.DataItem,"LessAnnualTaken") %>'
runat="server"></asp:Label>
</ItemTemplate>
</asp:TemplateColumn>

<asp:TemplateColumn HeaderText="Balance Annual Leave">
<ItemTemplate>
<asp:Label id="lblBalanceAnnualLeave" text='<%#
DataBinder.Eval(Container.DataItem,"BalanceAnnualLeave") %>'
runat="server"></asp:Label>
</ItemTemplate>
</asp:TemplateColumn>



<asp:ButtonColumn ButtonType="PushButton" CommandName="Edit"
Text="Edit" HeaderText="Update"></asp:ButtonColumn>
<asp:ButtonColumn ButtonType="PushButton"
CommandName="Delete" Text="Delete" HeaderText="Remove
Record"></asp:ButtonColumn>
</Columns>
</asp:DataGrid>

<font face="Arial Narrow"></font>
<font face="Arial Narrow"><font size="4">Total
Leave Taken :
<asp:TextBox id="txtTotalLeaveTaken"
runat="server" Width="35px"></asp:TextBox>
Days<asp:Button id="Button3" runat="server"
Text="Calculate"></asp:Button>
</font></font>
<font face="Arial Narrow">
<asp:Button id="Button4" runat="server" Width="82px"
Text="Back" Height="26px"></asp:Button>
</font><asp:Label id="MyJSLabel" runat="server"></asp:Label>
</form>
</body>
</html>