ASP.NET MVC, Webform hybrid

[WilliamT]

We (me and my team) have a ASP.NET MVC application and we are integrating a page or two that are Web Forms. We are trying to reuse the Master Page from our MVC part of the app in the WebForms part. We have found a way of rendering an MVC partial view in web forms, which works great, until we try and do a postback, which is the reason for using a WebForm. The Error:\[quote\] Validation of viewstate MAC failed. If this application is hosted by a Web Farm or cluster, ensure that configuration specifies the same validationKey and validation algorithm. AutoGenerate cannot be used in a cluster.\[/quote\]The Code to render the partial view from a WebForm (credited to "How to include a partial view inside a webform"):\[code\]public static class WebFormMVCUtil{ public static void RenderPartial(string partialName, object model) { //get a wrapper for the legacy WebForm context var httpCtx = new HttpContextWrapper(System.Web.HttpContext.Current); //create a mock route that points to the empty controller var rt = new RouteData(); rt.Values.Add("controller", "WebFormController"); //create a controller context for the route and http context var ctx = new ControllerContext( new RequestContext(httpCtx, rt), new WebFormController()); //find the partial view using the viewengine var view = ViewEngines.Engines.FindPartialView(ctx, partialName).View; //create a view context and assign the model var vctx = new ViewContext(ctx, view, new ViewDataDictionary { Model = model }, new TempDataDictionary()); //ERROR OCCURS ON THIS LINE view.Render(vctx, System.Web.HttpContext.Current.Response.Output); } }\[/code\]My only experience with this error is in context of a web farm, which is not the case. Also, I understand that the machine key is used for decrypting the ViewState. Any information on how to diagnose this issue would be appreciated.A Work-around:So far the work-around is to move the header content to a PartialView, then use an AJAX call to call a page with just the Partial View from the WebForms, and then using the PartialView directly on the MVC Views. Also, we are still able to share non-tech-specific parts of the Master Page, i.e. anything that is not MVC specific. Still yet, this is not an ideal solution, a server-side solution is still desired.Also, this solutino has issues when working with controls that have more sophisticated controls, using JavaScript, particularly dynamically generated script as used by 3rd party controls.