Question

I have a System.Web.UI.UserControl in my application which is to be used to display messages to the user, however after these messages are displayed to the user once I want them to clear (conditionally).

The simplified code I have now that I am trying to get to work is the following:

protected override void OnUnload(EventArgs e) {
if (_resetOnUnload) {
    divMessageBlock.InnerHtml = "";
    _resetOnUnload = false;
}
base.OnUnload(e);
}

However any changes to the view in the OnUnload event do not get transferred over on the next page load (form submit).

My question is how would I setup this user control to clear itself either before any messages can be added elsewhere or after the page has been rendered for the user and have stay that way?

Answer 1

Try this. Set the viewstate to save _resetOnUnload and then load it. OnLoad can stay the same, testing whether or not to clear.

protected override void OnLoad(EventArgs e) {
          base.OnLoad(e);

          if (_resetOnUnload) {
                 divMessageBlock.InnerHtml = "";
                 _resetOnUnload = false;
          }
   }

   protected override void LoadViewState(object savedState) {
          if (savedState != null) {
                 object[] myState = (object[])savedState;
                 _resetOnUnload = (bool)myState[0];
          }
   }

   protected override object SaveViewState() {
          object[] allStates = new object[]{ _resetOnUnload };
          return allStates;
   }