How does Page.IsValid work?
- by Lijo
I have following code with a RequiredFieldValidator. The EnableClientScript property is set as "false" in the validation control. Also I have disabled script in browser.
I am NOT using Page.IsValid in code behind. Still, when I submit without any value in textbox I will get error message.
From comments of @Dai, I came to know that this can be an issue, if there is any code in Page_Load that is executed in a postback. There will be no validation errors thrown.
(However, for button click handler, there is no need to check Page.IsValid)
if (Page.IsPostBack)
{
string value = txtEmpName.Text;
txtEmpName.Text = value + "Appended";
}
QUESTION
Why the server side validation does not happen before Page_Load?
Why it works fine when I use Page.IsValid?
UPDATE
It seems like, we need to add If(Page.IsValid) in button click also if we are using a Custom Validator with server side validation. Refer CustomValidator not working well.
Note: Client side validation question is present here: Whether to use Page_IsValid or Page_ClientValidate() (for Client Side Events)
MARKUP
<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
<title></title>
<script type="text/javascript">
alert('haiii');
</script>
</head>
<body>
<form id="form1" runat="server">
<div>
<asp:ValidationSummary runat="server" ID="vsumAll" DisplayMode="BulletList" CssClass="validationsummary" ValidationGroup="ButtonClick" />
<asp:TextBox ID="txtEmpName" runat="server"></asp:TextBox>
<asp:RequiredFieldValidator ID="valEmpName" runat="server" ControlToValidate="txtEmpName"
EnableClientScript="false" ErrorMessage="RequiredFieldValidator" Text="*" Display="Dynamic"
ValidationGroup="ButtonClick"></asp:RequiredFieldValidator>
<asp:Button ID="Button1" runat="server" onclick="Button1_Click" Text="Button" ValidationGroup="ButtonClick" />
</div>
</form>
</body>
</html>
CODE BEHIND
protected void Button1_Click(object sender, EventArgs e)
{
string value = txtEmpName.Text;
SubmitEmployee(value);
}
References:
Should I always call Page.IsValid?
ASP.NET Validation Controls – Important Points, Tips and Tricks
CustomValidator not working well
