viewstate - ASP.NET CheckBox does not fire CheckedChanged event when unchecking

Question

I have a CheckBox on an ASP.NET Content Form like so:

<asp:CheckBox runat="server" ID="chkTest" AutoPostBack="true" OnCheckedChanged="chkTest_CheckedChanged" />

In my code behind I have the following method:

protected void chkTest_CheckedChanged(object sender, EventArgs e)
{
}

When I load the page in the browser and click the CheckBox it becomes checked, the page posts back, and I can see chkTest_CheckedChanged being called.

When I then click the CheckBox again it becomes unchecked, the page posts back, however chkTest_CheckedChanged is not called.

The process is repeatable, so once the CheckBox is unchecked, checking it will fire the event.

I have View State disabled in the Web.Config, enabling View State causes this issue to disappear. What can I do to have reliable event firing while the View State remains disabled?

Update: If I set Checked="true" on the server tag the situation becomes reversed with the event firing when un-checking the CheckBox, but not the other way around.

Update 2: I've overridden OnLoadComplete in my page and from within there I can confirm that Request.Form["__EVENTTARGET"] is set correctly to the ID of my CheckBox.

Answer 1

To fire CheckedChanged event set the following properties for CheckBox, AutoPostBack property should be true and should have a default value either checked false or true.

AutoPostBack="true" Checked="false"