JSON parsing in webservice and returning a value

I am working on a webservice and a jQuery AJAX. It would take a modal dialog and get the inputs from the modal dialog put it into an object and then return a boolean result back from the webservice to the jQuery AJAX call.

Here is the code:

$('[id*="dialog"]').dialog({
    autoOpen: false,
    modal: true,
    resizable: false,
    show: "blind",
    hide: "puff",
    buttons: {
        'Create': function() {
            Materials.MaterialName = $('[id*="txtMaterialName"]').val();
            Materials.QuantityType = $('[id*="txtquantity"]').val();
            var jsonMaterial = JSON.stringify(Materials);
            AddNewMaterial(jsonMaterial);
            $(this).dialog('close');
        },
        'Cancel': function() {
            $(this).dialog('close');
        }
    },
    close: function() {
         window.document.location = "ResourcePlanningMaster.aspx";          
    }
});

function AddNewMaterial(materials) {
$.ajax({
    type: 'POST',
    contentType: "application/json; charset=utf-8",
    url: 'Services/Service.asmx/AddNewMaterial',
    data: '{"Materials":"' + materials + '"}',
    dataType: "json",
    success: function(data, textStatus) {
        if (textStatus == "success") {
            if (data.d == true) {
                alert('New Item Added');
            }
        }
    },
    error: function(data, textStatus) {
        alert('An error has occured retrieving data!');
    }
});

}

and the we开发者_运维百科b service is as :

[WebMethod]
    [ScriptMethod]
    public String AddNewMaterial(String Materials)
    {
        Boolean Result = false;
        try
        {

            MaterialEntity Material = JsonConvert.DeserializeObject<MaterialEntity>(Materials);
            Result = JsonHelper.InsertMaterial(Material);
        }
        catch (Exception ex)
        {

            logger.Error(ex.Message);
            logger.Fatal(ex.InnerException);
        }
        return Result.ToString();
    }

the MaterialEntity Class :

 public class MaterialEntity
{
    public String MaterialName { get; set; }
    public String QuantityType { get; set; }
}

Now when I am invking the create button in web service then the error I am getting in data.responseText is :

{"Message":"Invalid object passed in, \u0027:\u0027 or \u0027}\u0027 expected. (17): {\"Materials\":\"{\"MaterialName\":\"assd\",\"QuantityType\":\"asd\"}\"}","StackTrace":"   at System.Web.Script.Serialization.JavaScriptObjectDeserializer.DeserializeDictionary(Int32 depth)\r\n   at System.Web.Script.Serialization.JavaScriptObjectDeserializer.DeserializeInternal(Int32 depth)\r\n   at System.Web.Script.Serialization.JavaScriptObjectDeserializer.BasicDeserialize(String input, Int32 depthLimit, JavaScriptSerializer serializer)\r\n   at System.Web.Script.Serialization.JavaScriptSerializer.Deserialize(JavaScriptSerializer serializer, String input, Type type, Int32 depthLimit)\r\n   at System.Web.Script.Serialization.JavaScriptSerializer.Deserialize[T](String input)\r\n   at System.Web.Script.Services.RestHandler.GetRawParamsFromPostRequest(HttpContext context, JavaScriptSerializer serializer)\r\n   at System.Web.Script.Services.RestHandler.GetRawParams(WebServiceMethodData methodData, HttpContext context)\r\n   at System.Web.Script.Services.RestHandler.ExecuteWebServiceCall(HttpContext context, WebServiceMethodData methodData)","ExceptionType":"System.ArgumentException"}

Why am I getting this, even though I am parsing it quite correct as a json and then deserializing it as MaterialEntity Class itself? What's causing this error?

Try to use next code

data: '{"Materials":' + materials + '}',

instead of data line in your example (without double quotes around MaterialEntity object).