GridView RequiredFieldValidator Display

AG · Oct 15, 2006

Below is code (slightly modified and converted to VB) that was provided to
me in response to another post. I am using it to demonstrate another
problem.

In order for paging and other features to work properly in a gridview,
viewstate must be enabled. So, in order to minimize the size of viewstate
for a page, I will sometimes turn off viewstate for each control in template
columns.

That means that the gridview must be databound on each postback, which is
ok.

I have two questions.

1. Why does the RowCommand event fire twice?

2. In the below sample, I have a button and textbox in the gridview's footer
for adding a new record. Also a requiredfieldvalidator.

Clientscript has been disabled for the validator to simulate a browser with
javascript disabled.

In the RowCommand event, I validate the page for the appropriate group.

My problem is that the validator does not display it's error message if I
re-bind the grid on postback.

If I don't re-bind the grid, the error message will display, but as I
mentioned, in some cases I do need to rebind on every postback.

Is there a way to force the validator to display the error message?

TIA

<%@ Page Language="VB" AutoEventWireup="false" CodeFile="Default2.aspx.vb"
Inherits="Default2" %>

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">

<html xmlns="http://www.w3.org/1999/xhtml" >

<head runat="server">

<title>Untitled Page</title>

</head>

<body>

<form id="form1" runat="server">

<div>

<asp:GridView ID="GridView1" runat="server"

AutoGenerateColumns="false" OnRowCommand="GridView1_RowCommand"

OnRowDeleting="GridView1_RowDeleting" OnRowEditing="GridView1_RowEditing"

ShowFooter="True">

<Columns>

<asp:BoundField DataField="CategoryID"

HeaderText="CategoryID" />

<asp:BoundField DataField="CategoryName"

HeaderText="CategoryName" />

<asp:BoundField DataField="Description"

HeaderText="Description" />

<asp:TemplateField HeaderText="TemplateField">

<ItemTemplate>

<asp:Button ID="btnEdit" runat="server" Text="Edit"

CommandName="Edit" EnableViewState="False" />

<asp:ImageButton ID="imgBtn" runat="server"

ImageUrl="http://wcf.netfx3.com/Themes/default/images/logo.gif"

CommandName="Edit" EnableViewState="False" />

</ItemTemplate>

<FooterTemplate>

<asp:Button ID="btnInsert" runat="server" Text="Insert"

CommandName="Insert" ValidationGroup="Group1" EnableViewState="False" />

<asp:TextBox ID="TextBox1" runat="server"></asp:TextBox>

<asp:RequiredFieldValidator ID="RequiredFieldValidator2" runat="server"
ControlToValidate="TextBox1"

Display="Dynamic" EnableClientScript="False" EnableViewState="False"
ErrorMessage="Required" ValidationGroup="Group1"
SetFocusOnError="True"></asp:RequiredFieldValidator>

</FooterTemplate>

</asp:TemplateField>

<asp:CommandField ShowDeleteButton="True" />

</Columns>

</asp:GridView>

 <br />

</div>

</form>

</body>

</html>

Partial Class Default2

Inherits System.Web.UI.Page

Private Sub BindGrid()

Dim categories(10) As CategoryVO

Dim i As Integer

For i = 0 To categories.Length - 1

Dim vo As New CategoryVO()

vo.CategoryID = i + 1

vo.CategoryName = "Category_" + vo.CategoryID.ToString

vo.Description = "Description of " + vo.CategoryName

categories(i) = vo

Next i

GridView1.DataSource = categories

GridView1.DataBind()

End Sub

Protected Sub GridView1_RowCommand(ByVal sender As Object, ByVal e As
System.Web.UI.WebControls.GridViewCommandEventArgs) Handles
GridView1.RowCommand

Response.Write("<br/>GridView1_RowCommand: " + e.CommandName)

Me.Page.Validate("Group1")

Response.Write("<br/>GridView1_RowCommand: IsValid = " +
Page.IsValid.ToString)

End Sub

Protected Sub GridView1_RowDeleting(ByVal sender As Object, ByVal e As
GridViewDeleteEventArgs)

Response.Write(("<br/>GridView1_RowDeleting " + e.RowIndex.ToString))

End Sub

Protected Sub GridView1_RowEditing(ByVal sender As Object, ByVal e As
GridViewEditEventArgs)

Response.Write(("<br/>GridView1_RowEditing " + e.NewEditIndex.ToString))

End Sub

Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs)
Handles Me.Load

If Not IsPostBack Then

'BindGrid()

End If

End Sub

Protected Sub Page_PreRender(ByVal sender As Object, ByVal e As
System.EventArgs) Handles Me.PreRender

BindGrid()

End Sub

End Class

Walter Wang [MSFT] · Oct 16, 2006

Hi AG,

1. Why does the RowCommand event fire twice?

It's because you handled the RowCommand event twice: one is defined in your
ASPX: OnRowCommand="GridView1_RowCommand"; another is defined by your
code-behind: Protected Sub GridView1_RowCommand(ByVal sender As Object,
ByVal e As
System.Web.UI.WebControls.GridViewCommandEventArgs) Handles
GridView1.RowCommand

You need to remove one.

2. ... Is there a way to force the validator to display the error message?

In the RowCommand event, you can see the validator is actually working
correctly (Page.IsValid will be false if the TextBox is not filled in);
however, when you rebind the Grid in PreRender, the validator loses the
information about the state that an error message should be displayed if
the control failed to validate.

I think when the page is invalid, the GridView doesn't need rebinding
again.

I recommend use following workaround:

Dim flag1 As Boolean = False

Protected Sub GridView1_RowCommand(ByVal sender As Object, ByVal e As
System.Web.UI.WebControls.GridViewCommandEventArgs)
Response.Write("<br/>GridView1_RowCommand: " + e.CommandName)
Me.Page.Validate("Group1")
flag1 = Not Page.IsValid
Response.Write("<br/>GridView1_RowCommand: IsValid = " +
Page.IsValid.ToString)
End Sub

Protected Sub Page_PreRender(ByVal sender As Object, ByVal e As
System.EventArgs) Handles Me.PreRender
If Not flag1 Then
BindGrid()
Response.Write("<br/>PreRender and rebind")
End If
End Sub

Please test this and let me know whether or not this works for you. Thanks.

Sincerely,
Walter Wang ([email protected], remove 'online.')
Microsoft Online Community Support

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Walter Wang [MSFT] · Oct 16, 2006

Hi AG,

After a second thought, I think the better workaround would be
re-validating in PreRender when it's invalid:

Protected Sub Page_PreRender(ByVal sender As Object, ByVal e As
System.EventArgs) Handles Me.PreRender
BindGrid()
If flag1 Then Page.Validate("Group1")
Response.Write("<br/>PreRender and rebind")
End Sub

This way, the controls that have ViewState disabled will not lose the data
when the postback is caused by the Insert command.

Regards,
Walter Wang ([email protected], remove 'online.')
Microsoft Online Community Support

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AG · Oct 16, 2006

Thanks Walter,

Both items resolved!

turkush · Sep 1, 2007

Hi,

I hav the same prob my onRowCommand event fires twice...wot to do...

turkush · Sep 1, 2007

I hav the same prob that my onRowCommand fires twice...wot to do???

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GridView RequiredFieldValidator Display

AG

Walter Wang [MSFT]

Walter Wang [MSFT]

AG

turkush

turkush

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