Confusing results with CustomValidator and Datagrid controls

's Computer Specifications

Below is a cut-and-paste code example that runs. It demonstrates some
results which confuse me.

It uses a DataGrid to make a table with 12 rows, each containing a
TextBox and a CustomValidator. When a textbox is populated, the
validator should write out the index of the row that triggered it. And
it does--twice.

e.g. If you type something into the first row, you see "0 0." If you
type something into the first and third rows, you see "0 2 0 2." I
would only expect to see one set of results. (I only /want/ one set of
results.) Can anyone explain why I'm seeing /two/?

<%@ page language="vb" runat="server" Debug="true"%>

<script runat="server">
Sub Page_Load(sender as Object, e as EventArgs)
If ( IsPostBack ) Then
Validate()
Else
Dim numArray(12) As Integer

OurDataGrid.DataSource = numArray
OurDataGrid.DataBind()
End If
End Sub

Sub WriteIndex(source as Object, value as ServerValidateEventArgs)
Response.Write(source.Parent.Parent.ItemIndex & "<br>")
End Sub
</script>

<html><body>

<form runat="server">
<asp:Label id="OurLabel" runat="server" /><br />

<asp

ataGrid id="OurDataGrid"
AutoGenerateColumns="false"
runat="server">
<Columns>
<asp:TemplateColumn>
<HeaderTemplate></HeaderTemplate>
<ItemTemplate>
<asp:TextBox id="firstName" runat="server" />
<asp:CustomValidator id="OurCustomValidator"
ControlToValidate="firstName"
OnServerValidate="WriteIndex"
runat="server"></asp:CustomValidator>
</ItemTemplate>
<FooterTemplate></FooterTemplate>
</asp:TemplateColumn>
</Columns>
</asp

ataGrid>

<p>
<asp:Button text="Submit" runat="server" />
</p>
</form>

</body></html>

's Computer Specifications

Try stepping through it in the debugger. I bet you'll see that a
breakpoint set in WriteIndex will fire before a breakpoint set at
Validate() in your PageLoad.

As in, the custom validator will fire all by itself. You've instructed
it to fire again in your pageLoad, so you're seeing its results twice.

Good luck!
Jason
Expat Software Consulting Services
http://www.expatsoftware.com/

's Computer Specifications

Just a clarification.

The Button, LinkButton and ImageButton controls all automatically call
Page.Validate() for you when their CausesValidation property is true (which
is the default). They call it after Page_Load and immediately before calling
your Click event handler.

As you know from the answer below, by adding another call to Validate in
Page_Load, it is called twice. As a general rule, try to avoid calling
Validate in Page_Load. If CausesValidation is false, you should call it in
your Click post back event handler before saving data.

ALWAYS remember to check Page.IsValid is true in Click before saving.

--- Peter Blum
www.PeterBlum.com
Email: (E-Mail Removed)
Creator of "Professional Validation And More" at
http://www.peterblum.com/vam/home.aspx

"jasonkester" <(E-Mail Removed)> wrote in message
news:(E-Mail Removed)...
> Try stepping through it in the debugger. I bet you'll see that a
> breakpoint set in WriteIndex will fire before a breakpoint set at
> Validate() in your PageLoad.
>
> As in, the custom validator will fire all by itself. You've instructed
> it to fire again in your pageLoad, so you're seeing its results twice.
>
> Good luck!
> Jason
> Expat Software Consulting Services
> http://www.expatsoftware.com/
>

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