ASP.NET Web Service使用参数返回IndexOutOfRangeException

Question

I have the following web service:

[ScriptService]
public class Handler : WebService {

    [WebMethod]
    public void method1() {

        string json = "{ \"success\": true }";

        System.Web.HttpContext.Current.Response.Write(json);

    }

    [WebMethod]
    public object method2(Dictionary<string, object> d) {

        Dictionary<string, object> response = new Dictionary<string, object>();

        response.Add("success", true);

        return response;

    }

}

The first method accepts a traditional html form post and response writes a JSON string to the page. The second method accepts a JSON value posted via AJAX and returns a serialized object.

Both these methods work fine on their own but when put together in the same web service I get this error when calling method1:

System.IndexOutOfRangeException: Index was outside the bounds of the array.

When I remove the arguments from method2 they work.

Can anyone suggest why this is happening?

Edit:

The problem spans from the argument type of method2. If I change it to a string or simple data type it works fine. As Joel suggests it's probably because Dictionaries can't be serialized. This doesn't seem to affect my requests sent by ajax and only breaks direct form posts to this handler. Therefore my workaround is to put the form post handlers in a separate file by themselves. Not ideal but works for my application.

Answer 1

Dictionaries are not serializable. Hiding it behind an object doesn't do anything for you. You must first convert your dictionary to an array or some other serializable object before sending it out.

Why isn't there an XML-serializable dictionary in .NET? http://weblogs.asp.net/pwelter34/archive/2006/05/03/444961.aspx http://www.tanguay.info/web/index.php?pg=codeExamples&id=333