Passing data to ASP.NET webservice using JSON

Question

Hi all,

I have successfully returned data from a ASP.Net webservice in JSON format (using a service method that required no parameters) but have struggled with making a webservice call that requires a parameter.

Webservice:

<WebMethod()> _
<ScriptMethod(ResponseFormat:=ResponseFormat.Json, UseHttpGet:=True)> _
Public Function TestWebService(ByVal Description As String) As Stock
    Dim res As New Stock(Guid.NewGuid, Description)
    Return res
End Function

Object:

Public Class Stock

    Public Sub New()
    End Sub

    Public Sub New(ByVal StockID As Guid, ByVal Description As String)
        Me._StockID = StockID
        Me._Description = Description
    End Sub


    Public Property StockID As Guid
    Public Property Description As String

End Class

Javascript:

client = window.XMLHttpRequest ? new XMLHttpRequest() : new ActiveXObject("Microsoft.XMLHTTP");
client.onreadystatechange = DataReturnedFromHttpRequest;
client.open("GET", "/MyWebService.asmx/TestWebService?" + JSON.stringify({"Description":["Test"]}), true); 
client.setRequestHeader("Content-Type", "application/json");
client.send(null);

Response:

{"Message":"Invalid web service call, missing value for parameter: \u0027Description\u0027.","StackTrace":"   at System.Web.Script.Services.WebServiceMethodData.CallMethod(Object target, IDictionary`2 parameters)\r\n   at System.Web.Script.Services.WebServiceMethodData.CallMethodFromRawParams(Object target, IDictionary`2 parameters)\r\n   at System.Web.Script.Services.RestHandler.InvokeMethod(HttpContext context, WebServiceMethodData methodData, IDictionary`2 rawParams)\r\n   at System.Web.Script.Services.RestHandler.ExecuteWebServiceCall(HttpContext context, WebServiceMethodData methodData)","ExceptionType":"System.InvalidOperationException"}

I understand the error but cant seem to work out how to format my request correctly.

Answer 1

Finally got it... So for anyone curious the answer was trival.

The get request must be in the following format

/MyWebService.asmx/MyWebserviceMethod?Param1=%22ParamValue1%22&Param2=%22ParamValue2

Then it works like a charm.