For developers: Use a cache substitution widget

To substitute the cache for a particular widget, you create a custom cache substitution widget and place it on the page. The widget utilizes the ASP.NET cache substitution. You create a static method that registers with the ASP.NET implementation of cache substitution. Inside this method, you must render the content of the widget.

Create a User widget with the following markup:

If the widget, you want to substitute, inherits from SimpleView, which in turn inherits from System.Web.UI.WebControls.WebControl, you can override the RenderContents(System.Web.UI.HtmlTextWriter writer) method. Inside, you call your own implementation for performing cache substitution.

When output cache is used on the page, you substitute it with the CacheSubstitutionWrapper in DoPostCacheSubstitution() method by forming a dictionary of parameters and passing it to a CacheSubstitutionWrapper.RenderMarkupDelegate that afterwards renders the correct markup.

IMPORTANT: Do not pass entire objects, such as a page, a control instance, property of the control, etc. This will cause serious memory leaks. When you need to pass a property value, you must use its string representation.

Following is a code sample of the code-behind file: