Question

I have a scenario where I’d like to render an ActionLink programmatically, ether from a controller or ideally an extension method. This is so I can wrap up some logic of wether to display the link and remove that logic from my view.

I can create an ActionLink using the MVC Futures project from CodePlex.

ActionLink actionLink = new ActionLink();
actionLink.ActionName = "MyActionName";
actionLink.ControllerName = "MyControllerName";

There is a RenderControl method that takes a HtmlTextWriter which I’ve been trying to use. I can’t get this to work and a null reference exception is thrown each time within the Microsoft.Web.Mvc assembly (Futures).

[NullReferenceException: Object reference not set to an instance of an object.]
   Microsoft.Web.Mvc.Controls.ActionLink.Render(HtmlTextWriter writer) +643
   System.Web.UI.Control.RenderControlInternal(HtmlTextWriter writer, ControlAdapter adapter) +27
   System.Web.UI.Control.RenderControl(HtmlTextWriter writer, ControlAdapter adapter) +99
   System.Web.UI.Control.RenderControl(HtmlTextWriter writer) +25
   MvcSpike.Controllers.HomeController.Index() in C:\...\Controllers\HomeController.cs:33
   lambda_method(ExecutionScope , ControllerBase , Object[] ) +74
   System.Web.Mvc.ActionMethodDispatcher.Execute(ControllerBase controller, Object[] parameters) +17
   System.Web.Mvc.ReflectedActionDescriptor.Execute(ControllerContext controllerContext, IDictionary`2 parameters) +178
   System.Web.Mvc.ControllerActionInvoker.InvokeActionMethod(ControllerContext controllerContext, ActionDescriptor actionDescriptor, IDictionary`2 parameters) +24
   System.Web.Mvc.<>c__DisplayClassd.<InvokeActionMethodWithFilters>b__a() +52
   System.Web.Mvc.ControllerActionInvoker.InvokeActionMethodFilter(IActionFilter filter, ActionExecutingContext preContext, Func`1 continuation) +254
   System.Web.Mvc.<>c__DisplayClassf.<InvokeActionMethodWithFilters>b__c() +19
   System.Web.Mvc.ControllerActionInvoker.InvokeActionMethodWithFilters(ControllerContext controllerContext, IList`1 filters, ActionDescriptor actionDescriptor, IDictionary`2 parameters) +192
   System.Web.Mvc.ControllerActionInvoker.InvokeAction(ControllerContext controllerContext, String actionName) +314
   System.Web.Mvc.Controller.ExecuteCore() +105
   System.Web.Mvc.ControllerBase.Execute(RequestContext requestContext) +39
   System.Web.Mvc.ControllerBase.System.Web.Mvc.IController.Execute(RequestContext requestContext) +7
   System.Web.Mvc.<>c__DisplayClass8.<BeginProcessRequest>b__4() +34
   System.Web.Mvc.Async.<>c__DisplayClass1.<MakeVoidDelegate>b__0() +21
   System.Web.Mvc.Async.<>c__DisplayClass8`1.<BeginSynchronous>b__7(IAsyncResult _) +12
   System.Web.Mvc.Async.WrappedAsyncResult`1.End() +59
   System.Web.Mvc.MvcHandler.EndProcessRequest(IAsyncResult asyncResult) +44
   System.Web.Mvc.MvcHandler.System.Web.IHttpAsyncHandler.EndProcessRequest(IAsyncResult result) +7
   System.Web.CallHandlerExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute() +8679150
   System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously) +155

Any help would be great.

Answer 1

Assuming you’re in a controller, you could use the following:

string anchor = HtmlHelper.GenerateLink(
                    this.Request.RequestContext,
                    RouteTable.Routes,
                    "Link name",
                    "",
                    "MyActionName",
                    "MyControllerName",
                    null,
                    null);

But I’m not entirely sure what exactly you want to see in the end.