[Solved] ASP.Net Error: Page.IsValid cannot be called before validation has taken place

Hi samsmuthu,

You must call Page.IsValid method before the Page.IsValid property to force validation manually.

HTML

<div class="form">
    <asp:UpdatePanel ID="UpdatePanelSub" runat="server">
        <ContentTemplate>
            <asp:TextBox ID="TxtSubscribeEmail" runat="server" placeholder="enter your email" TextMode="Email" CssClass="email"></asp:TextBox>
            <asp:RequiredFieldValidator ID="RequiredFieldValidator2" runat="server"
                ControlToValidate="TxtSubscribeEmail" Display="Dynamic"
                ErrorMessage="* Email required." Font-Size="Small"
                ForeColor="red" SetFocusOnError="True"></asp:RequiredFieldValidator>
            <asp:RegularExpressionValidator ID="RegularExpressionValidator1" runat="server"
                ControlToValidate="TxtSubscribeEmail" Display="Dynamic"
                ErrorMessage="* Email address wrong." Font-Size="Small"
                ForeColor="red" SetFocusOnError="True"
                ValidationExpression=".*@.*\..*"></asp:RegularExpressionValidator>
            <span>
                <asp:Label ID="LblMessage" runat="server"></asp:Label></span>
            <asp:Button ID="BtnSubscribe" runat="server" Text="subscribe" CssClass="btn" OnClick="BtnSubscribe_Click" CausesValidation="false" />
        </ContentTemplate>
    </asp:UpdatePanel>
</div>

Code

C#

protected void BtnSubscribe_Click(object sender, EventArgs e)
{
    Page.Validate();
    if (Page.IsValid)
    {
    }
}

VB.Net

Protected Sub BtnSubscribe_Click(ByVal sender As Object, ByVal e As EventArgs)
    Page.Validate()
    If Page.IsValid Then
    End If
End Sub