I am getting this error message.

Server Error in '/' Application.
Operation is not valid due to the current state of the object.
Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code.

Exception Details: System.InvalidOperationException: Operation is not valid due to the current state of the object.

Source Error:

An unhandled exception was generated during the execution of the current web request. Information regarding the origin and location of the exception can be identified using the exception stack trace below.

Stack Trace:

[InvalidOperationException: Operation is not valid due to the current state of the object.]
   System.Web.HttpValueCollection.ThrowIfMaxHttpCollectionKeysExceeded() +2420322
   System.Web.HttpValueCollection.FillFromEncodedBytes(Byte[] bytes, Encoding encoding) +58
   System.Web.HttpRequest.FillInFormCollection() +159

[HttpException (0x80004005): The URL-encoded form data is not valid.]
   System.Web.HttpRequest.FillInFormCollection() +217
   System.Web.HttpRequest.get_Form() +104
   Microsoft.Web.Infrastructure.DynamicValidationHelper.<>c__DisplayClass8.<MakeCollectionsLazy>b__2() +12
   Microsoft.Web.Infrastructure.DynamicValidationHelper.<>c__DisplayClass12.<ReplaceCollection>b__e() +61
   Microsoft.Web.Infrastructure.DynamicValidationHelper.<>c__DisplayClass12.<ReplaceCollection>b__11() +17
   Microsoft.Web.Infrastructure.DynamicValidationHelper.DeferredCountArrayList.get_Count() +17
   System.Collections.Specialized.NameObjectCollectionBase.get_Count() +15
   System.Web.HttpRequest.ValidateNameValueCollection(NameValueCollection nvc, RequestValidationSource requestCollection) +23
   System.Web.HttpRequest.get_Form() +150
   System.Web.HttpRequestWrapper.get_Form() +11
   System.Web.Mvc.HttpRequestExtensions.GetHttpMethodOverride(HttpRequestBase request) +126
   System.Web.Mvc.AcceptVerbsAttribute.IsValidForRequest(ControllerContext controllerContext, MethodInfo methodInfo) +41
   System.Web.Mvc.HttpGetAttribute.IsValidForRequest(ControllerContext controllerContext, MethodInfo methodInfo) +40
   System.Web.Mvc.<>c__DisplayClass11.<RunSelectionFilters>b__d(ActionMethodSelectorAttribute attr) +24
   System.Linq.Enumerable.All(IEnumerable`1 source, Func`2 predicate) +145
   System.Web.Mvc.ActionMethodSelector.RunSelectionFilters(ControllerContext controllerContext, List`1 methodInfos) +319
   System.Web.Mvc.ActionMethodSelector.FindActionMethod(ControllerContext controllerContext, String actionName) +59
   System.Web.Mvc.ReflectedControllerDescriptor.FindAction(ControllerContext controllerContext, String actionName) +62
   System.Web.Mvc.ControllerActionInvoker.FindAction(ControllerContext controllerContext, ControllerDescriptor controllerDescriptor, String actionName) +16
   System.Web.Mvc.ControllerActionInvoker.InvokeAction(ControllerContext controllerContext, String actionName) +105
   System.Web.Mvc.Controller.ExecuteCore() +116
   System.Web.Mvc.ControllerBase.Execute(RequestContext requestContext) +97
   System.Web.Mvc.ControllerBase.System.Web.Mvc.IController.Execute(RequestContext requestContext) +10
   System.Web.Mvc.<>c__DisplayClassb.<BeginProcessRequest>b__5() +37
   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() +62
   System.Web.Mvc.<>c__DisplayClasse.<EndProcessRequest>b__d() +50
   System.Web.Mvc.SecurityUtil.<GetCallInAppTrustThunk>b__0(Action f) +7
   System.Web.Mvc.SecurityUtil.ProcessInApplicationTrust(Action action) +22
   System.Web.Mvc.MvcHandler.EndProcessRequest(IAsyncResult asyncResult) +60
   System.Web.Mvc.MvcHandler.System.Web.IHttpAsyncHandler.EndProcessRequest(IAsyncResult result) +9
   System.Web.CallHandlerExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute() +8969201
   System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously) +184


Version Information: Microsoft .NET Framework Version:4.0.30319; ASP.NET Version:4.0.30319.272 

I have tried doing the suggested fix off

<appSettings>
   <add key="aspnet:MaxHttpCollectionKeys" value="1001" />
</appSettings>

I tried putting it at some crazy number

<add key="aspnet:MaxHttpCollectionKeys" value="10000000000" />

yet it still gives me the same error (I have alot of fields but not that many). I am using asp.net mvc 3 (razor). I am using .net 4.0.

I am sending the whole form by jquery ajax(seralizeArrary) so I don't know if that has something to do with it or not.

• asp.net
• .net
• asp.net-mvc-3
• post
• web-config

Use a more reasonable value such as 32000, that works fine for me.

Is there a way also to limit it to which forms this is allowed on and not global as it seems to be right now?

No, I don't think that is is possible to handle this setting per form. This is because the values are parsed very eary before the routing takes place, but only after routing it would be known what "form" this belongs to.

Following are the limits:

1. MaxHttpCollectionKeys is an int, so it could have a max value of an integer (int.MaxValue: 2,147,483,647)
2. Minimum value is 1
3. Default value is 1000

Check on MSDN