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PODeserializing json from client in json.net 3.5b2 in vb.net
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  1. PODeserializing json from client in json.net 3.5b2 in vb.net
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    copied!<p>I have a test case of a problem I'm having, basically I create a json object on the server and provide it back to an AJAX called made on the client side. That works fine, however, when I try to send it back and deserialize it server side I get the following exception:</p> <blockquote> <p><strong>No parameterless constructor defined for type of 'System.String'.</strong></p> <p>System.MissingMethodException at System.Web.Script.Serialization.ObjectConverter.ConvertDictionaryToObject(IDictionary<code>2 dictionary, Type type, JavaScriptSerializer serializer, Boolean throwOnError, Object&amp; convertedObject) at system.Web.Script.Serialization.ObjectConverter.ConvertObjectToTypeInternal(Object o, Type type, JavaScriptSerializer serializer, Boolean throwOnError, Object&amp; convertedObject) at system.Web.Script.Serialization.ObjectConverter.ConvertObjectToTypeMain(Object o, Type type, JavaScriptSerializer serializer, Boolean throwOnError, Object&amp; convertedObject) at System.Web.Script.Serialization.ObjectConverter.ConvertObjectToType(Object o, Type type, JavaScriptSerializer serializer) at System.Web.Script.Services.WebServiceMethodData.StrongTypeParameters(IDictionary</code>2 rawParams) at System.Web.Script.Services.WebServiceMethodData.CallMethodFromRawParams(Object target, IDictionary<code>2 parameters) at System.Web.Script.Services.RestHandler.InvokeMethod(HttpContext context, WebServiceMethodData methodData, IDictionary</code>2 rawParams) at System.Web.Script.Services.RestHandler.ExecuteWebServiceCall(HttpContext context, WebServiceMethodData methodData)</p> </blockquote> <p><strong>Default.aspx</strong></p> <pre><code>&lt;%@ Page Language="VB" AutoEventWireup="false" CodeFile="Default.aspx.vb" Inherits="_Default" %&gt; &lt;!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"&gt; &lt;html xmlns="http://www.w3.org/1999/xhtml"&gt; &lt;head runat="server"&gt; &lt;title&gt;Untitled Page&lt;/title&gt; &lt;script src="http://www.json.org/json2.js" type="text/javascript"&gt;&lt;/script&gt; &lt;script src="http://code.jquery.com/jquery-latest.pack.js" type="text/javascript" &gt;&lt;/script&gt; &lt;script type="text/javascript"&gt; $(document).ready(function(){ $.theDate = {}; $("#Button1").click(function(){ $.ajax({ type: 'POST', url: 'default.aspx/getDate', data: '{}', contentType: 'application/json; charset=utf-8', dataType: 'json', success: function(json){ var date = eval("("+json.d+")"); $.theDate = date; var pdate = eval("("+json.d.replace(/"\\\/Date\(([0-9]+)[0-9-]+\)\\\/"/gi, 'new Date(parseInt($1,10))')+")"); $("#now").val(date.now); $("#pnow").val(pdate.now); $("#strnow").val(date.strnow); }, error: function(xmlhr, status, err){ console.error(arguments); var response = eval("("+xmlhr.responseText+")"); console.log(response); } }); }); $("#Button2").click(function(){ var json = JSON.stringify($.theDate); json = '{"json":'+json+'}'; $.ajax({ type:'POST', url:'default.aspx/deserialize', data: json, contentType:'application/json; charset=utf-8', dataType: 'json', success: function(json){ var date = eval("("+json.d+")"); console.log(date); }, error: function(xmlhr, status, err){ console.error(arguments); var response = eval("("+xmlhr.responseText+")"); console.log(response); } }); }); }); &lt;/script&gt; &lt;/head&gt; &lt;body&gt; &lt;form id="form1" runat="server"&gt; &lt;div&gt; &lt;input id="Button1" type="button" value="Get Date" /&gt;&lt;br /&gt; date.now: &lt;input type="text" id="now" value="" style="width:20em" /&gt;&lt;br /&gt; date.now processed: &lt;input type="text" id="pnow" value="" style="width:30em"&gt;&lt;br /&gt; date.strnow: &lt;input type="text" id="strnow" value="" style="width:20em"/&gt; &lt;input id="Button2" type="button" value="Send Date" /&gt;&lt;br /&gt; &lt;/div&gt; &lt;/form&gt; &lt;/body&gt; &lt;/html&gt; </code></pre> <p><strong>Default.aspx.vb</strong></p> <pre><code>Imports System.Web.Services Imports Newtonsoft.Json Partial Class _Default Inherits System.Web.UI.Page Private Class _date &lt;JsonProperty()&gt; Public now As New Date &lt;JsonProperty()&gt; Public strnow As String Public Sub New() now = Date.Today strnow = Date.Today.ToLongDateString End Sub End Class &lt;WebMethod()&gt; Public Shared Function getDate() As String Dim theDate As New _date Dim strJson As String strJson = JsonConvert.SerializeObject(theDate) Return strJson End Function &lt;WebMethod()&gt; Public Shared Function deserialize(ByVal json As String) As String Dim newDate As _date Try newDate = JsonConvert.DeserializeObject(json, GetType(_date)) Return "{""done"":true}" Catch ex As Exception Throw ex End Try End Function End Class </code></pre> <p>I'd greatly appreciate help on what I'm doing wrong here. Thanks in advance.</p>
 

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