ASP.NET - Making CustomValidator to check a control's property

Question

I have a User Control and it's got a bool IsValidDate property. How can I use CustomValidator to check for this value and return its error message if the value of the property is false?

Answer 1

If your user control looks something like this:

<%@ Control Language="C#" AutoEventWireup="true" CodeBehind="MyDateUserControl.ascx.cs" Inherits="CustomValidation.MyDateUserControl" %>

My custom user control
<asp:TextBox runat="server" ID="DateTextBox" />

<asp:CustomValidator  runat="server" ValidateEmptyText="true" ID="DateCustomValidator" ControlToValidate="DateTextBox"  OnServerValidate="DateCustomValidator_ServerValidate" ErrorMessage="The date is not valid" />

<asp:Button ID="SubmitButton" runat="server" Text="Submit" />

Then in your codebehind you can use:

public bool IsValidDate
{
    get
    {
        DateTime temp;
        return DateTime.TryParse(DateTextBox.Text, out temp);
    }
}

protected void DateCustomValidator_ServerValidate(object source, ServerValidateEventArgs args)
{
    args.IsValid = IsValidDate;
}

If you don't want your custom validator to be a part of your user control, you have to prefix IsValidDate with the name of your user control.