c＃jquery对象引用未设置为对象的实例

Question

I have a webservice in c# and I am calling it from my jquery script.

This is the webservice in c#

[WebMethod]
[ScriptMethod(UseHttpGet = true)]
public void LoadService2Daily(string fromDate, string toDate, string[] campaigns)

In script I do this:

var selectedCampaigns = $("#campaignDiv input:checkbox:checked").map(function () {
        return $(this).val();
    }).get();
    console.log(selectedCampaigns);


webServiceUrl = 'http://localhost:4025/vmp_webservice.asmx/LoadService2Daily';
$.getJSON(webServiceUrl,
      { fromDate: valFrom, toDate: valTo, campaigns: selectedCampaigns })
       .done(function (result) {

I got error 500 and when I check the response, it is Object reference not set to an instance of an object.

Note

If I removed the string[] array from the web service, it works perfectly, but when I add it, it stoped working. so I am sure it is because the string array thing but I don't know where exactly is the mistake.

The code without the array have been working for 3 years without any problem, but now I am making some editing and I need to pass that array.

This is a screenshot of the console.log to print the selectedCampgains. Notice that, as I showed you in the code, this log is taken before calling the web service

Edit

I noticed that the url of the web service is

Request URL:http://localhost:4025/vmp_webservice.asmx/LoadService2Daily?fromDate=2014-05-25+00%3A00%3A00&toDate=2014-05-25+23%3A59%3A01&campaigns%5B%5D=default&campaigns%5B%5D=Support

as it doesn't contain the string array, right?

Edit3

This is the whole exception that I get

System.NullReferenceException: Object reference not set to an instance of an object.
   at System.Web.Services.Protocols.ValueCollectionParameterReader.Read(NameValueCollection collection)
   at System.Web.Services.Protocols.UrlParameterReader.Read(HttpRequest request)
   at System.Web.Services.Protocols.HttpServerProtocol.ReadParameters()
   at System.Web.Services.Protocols.WebServiceHandler.CoreProcessRequest()

Answer 1

正在生成的网址带有方括号，您能否检查如果没有方括号即没有％5B和％5D（没有url编码）是否可以正常使用

http://localhost:4025/vmp_webservice.asmx/LoadService2Daily?fromDate=2014-05-25+00%3A00%3A00&toDate=2014-05-25+23%3A59%3A01&campaigns=default&campaigns=Support