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Editorial Team
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Asked: 2026-05-27T02:57:44+00:00

I’ve been successfully WebForms for AJAX calls with relatively complex set of parameters (called

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I’ve been successfully WebForms for AJAX calls with relatively complex set of parameters (called using jQuery.ajax). We’re attempting to try using the same approach in MVC 3 but seem to be falling at the first hurdle with MVC failing to deserialize Dictionary arrays successfully.

The approach that works without issue in ASP.NET WebForms “classic” is below:

[WebMethod]
public static JQGrid.JQGridData GetListForJQGrid(int? iPageSize, int? iPage, int? iMaxRecords, string sSortField, string sSortOrder,
  Dictionary<string, string> dSearchOptions, Dictionary<string, object>[] aOriginalColumnDefinition, string[] aExtraDataColumns)

And below is the MVC 3 equivalent: (nb exactly the same name/parameters – different return type but I don’t think that is relevant)

[HttpPost]
public JSONResult GetListForJQGrid(int? iPageSize, int? iPage, int? iMaxRecords, string sSortField, string sSortOrder,
  Dictionary<string, string> dSearchOptions, Dictionary<string, object>[] aOriginalColumnDefinition, string[] aExtraDataColumns)

With the WebMethod all the data deserializes perfectly. However, when the MVC method is called all the simple parameters deserialize fine but for some unknown reason the array of Dictionary’s arrives as an array of nulls.

So, off the back of that a number of questions:

  • Has anyone else experienced problems with MVC 3 deserialization of arrays of dictionaries?
  • Does MVC 3 by default not use System.Web.Script.Serialization.JavaScriptSerializer which is I think what ASP.NET WebMethods use under the bonnet?
  • Can I force MVC 3 to use System.Web.Script.Serialization.JavaScriptSerializer instead of what it is using?
  • Or am I missing something / should my approach be slightly different? Please note that at least for now we’ll need to share the client side code between classic ASP.NET WebMethods and MVC 3 and so we want that to remain as is if possible.
  • Finally, I can see there is a possible workaround that could be used looking at this question: POST json dictionary . Is this workaround the only game in town or have things improved since this question was posed?

jQuery AJAX call:

$.ajax(_oJQGProperties.sURL, //URL of WebService/PageMethod used
{
  data: JSON.stringify(oPostData),
  type: "POST",
  contentType: "application/json",
  complete: DataCallback
});

Example JSON.stringify(oPostData):

{
"dSearchOptions":{},
"aOriginalColumnDefinition":
[
{"name":"ID","sortable":false,"hidedlg":true,"align":"right","title":false,"width":40},
{"name":"URL","sortable":false,"hidedlg":true,"align":"left","title":false,"width":250,"link":"javascript:DoSummat(this,'{0}');","textfield":"Name"},
{"name":"Description","sortable":false,"hidedlg":true,"align":"left","title":false,"width":620}
],
"aExtraDataColumns":["Name"],
"_search":false,
"iPageSize":-1,
"iPage":1,
"sSortField":"",
"sSortOrder":"",
"iMaxRecords":0
}
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1 Answer

  1. Editorial Team

    Long time getting to update this but I thought I’d share where we got to. The problem turned out to be a bug – details of which can be found here:

    Bug:
    http://connect.microsoft.com/VisualStudio/feedback/details/636647/make-jsonvalueproviderfactory-work-with-dictionary-types-in-asp-net-mvc

    Workaround:
    POST json dictionary

    We used the stated workaround which has been fine. I’m not too clear as to when the fix will be shipped and where exactly the bug lay. (Is it .NET dependant / MVC dependant etc) If anyone else knows I’d love to find out 🙂

    Update

    I haven’t heard still if this is shipped (I assume it goes out with MVC 4?) but in the interim this may be an alternative solution:

    http://www.dalsoft.co.uk/blog/index.php/2012/01/10/asp-net-mvc-3-improved-jsonvalueproviderfactory-using-json-net/

    Update 2

    This has now been shipped as a fix with MVC 4. The issue remains unresolved in MVC 3 and so I’ve now written it up as a blog post here:

    http://icanmakethiswork.blogspot.com/2012/10/mvc-3-meet-dictionary.html

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