ASP.NET Charting Control no longer working with .NET 4

Question

I\'ve just upgraded to .NET 4 and my ASP.NET Chart Control no longer displays.

For .NET 3.5, the HTML produced by the control used to look like this:

Answer 1

While @Michael's solution is informative on why this problem exists, there is a simpler solution. When registering the routes in your controllers handle in global.asax.cs, you could add an ignored route with a contstraint, as follows:

protected void Application_Start() {
    ...
    RouteTable.Routes.Ignore("{*pathInfo}", new { pathInfo = @"^.*(ChartImg.axd)$" });
    ...
}