The purpose of this post is to raise your awareness of a toggle which exists in the DevExpress XAF framework which can significantly improve UI performance in the web application.

The biggest XAF project I work with has one very complex business object. The layout for this screen includes about 100 properties, several nested tabs, some custom editors, several collection properties and a whole lot of Conditional Appearance rules. It was very sluggish to navigate - it was taking several seconds to load the detail view and then it was very slow switching between tabs. Switching to edit mode was also slow.

Last week, I almost accidentally changed the value of DelayedViewItemsInitialization to false and noticed that the UI speed was much much better. In fact the general responsiveness of the entire web-application seems much better.

In order to give it a whirl, navigate to the WebApplication.cs file (normally in the ApplicationCode subfolder of your web project) and modify the constructor as follows:

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public MainDemoWebApplication() {
    InitializeComponent();
    this.DelayedViewItemsInitialization = false;
}

Certainly this is not without consequences, and I would urge a careful reading of the relevant documentation. To be honest, I still don’t really understand why my detail view is so much slower without this change. I have tried to isolate the cause without much success and I will update this post if I find anything new. But if some of your detail views seem overly slow, certainly try it out.