我收到了以下错误:
"Message":"No parameterless constructor defined for type of \u0027System.String\u0027.","StackTrace":" at System.Web.Script.Serialization.ObjectConverter.ConvertDictionaryToObject(IDictionary`2 dictionary, Type type, JavaScriptSerializer serializer, Boolean throwOnError, Object& convertedObject)\r\n at System.Web.Script.Serialization.ObjectConverter.ConvertObjectToTypeInternal(Object o, Type type, JavaScriptSerializer serializer, Boolean throwOnError, Object& convertedObject)\r\n at System.Web.Script.Serialization.ObjectConverter.ConvertObjectToTypeMain(Object o, Type type, JavaScriptSerializer serializer, Boolean throwOnError, Object& convertedObject)\r\n at System.Web.Script.Services.WebServiceMethodData.StrongTypeParameters(IDictionary`2 rawParams)\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.MissingMethodException"}
我假设发生了这种情况,因为我没有正确地从我的ajax帖子中传递一些东西,但是我看不到它:(。如果我没有传递任何参数,我从web方法中删除了参数它有效。但是,有了它们,它没有。另外,如果我尝试传递一个JSON对象它也不起作用。我在底部发布了这个代码。如果有人可以帮助我,我会很感激!感谢。
$.ajax({
type: "POST",
url: 'Process.aspx/updateAProcess',
data: JSON.stringify({ 'ProcessID': ProcessID, 'ProcessDescription': ProcessDescription, 'ProcessName': ProcessName }),
contentType: "application/json; charset=utf-8",
dataType: "json",
async: false,
success: function (data) {
alert("Winner!");
}
});
<System.Web.Services.WebMethod()> _
<System.Web.Script.Services.ScriptMethod()> _
Public Shared Function updateAProcess(ByVal ProcessID As String, ByVal ProcessDescription As String, ByVal ProcessName As String)
Dim pBSL As New ProcessBSL
pBSL.ProcessUpdate(ProcessID, ProcessDescription, ProcessName)
Return Nothing
End Function
这是我的数据通话:
data: JSON.stringify({ updateProcess: updateProcess }),
这是我创建updateProcess的地方:
var updateProcess = new Object();
updateProcess.ProcessName = $("#ProcessNameChange").val();
updateProcess.ProcessDescription = $("#ProcessDescChange").val();
updateProcess.ProcessID = $(this).closest("tr").children()[4];
导致此错误:
{"Message":"Invalid web service call, missing value for parameter: \u0027ProcessID\u0027.","StackTrace"
在后端,我有一个名为ProcessBO的对象,它有十几个属性,我的webmethod是:
Public Shared Function update(ByVal updateProcess As ProcessBO)
Dim pBSL As New ProcessBSL
pBSL.ProcessUpdate(updateProcess.ProcessID, updateProcess.ProcessDescription, updateProcess.ProcessName)
Return Nothing
答案 0 :(得分:2)
出现错误消息是因为ASP.Net尝试解码参数时发生异常。不知何故,它的内部代码最终试图反序列化异常。
问题的根源在于您将字符串参数作为直接文本传递,而不是将它们封装在引号中。例如,如果ProcessID =“1”,ProcessDescription =“2”和ProcessName =“3”,则您的参数将如下所示:
{ 'ProcessID': 1, 'ProcessDescription': 2, 'ProcessName': 3 }
但它们应该看起来像
{ 'ProcessID': '1', 'ProcessDescription': '2', 'ProcessName': '3' }
我发现最简单,最安全的方法是实际创建一个带有相应参数的js类,用数据填充它,然后将这个类传递给stringify:
var params = new Object();
params.ProcessID = ProcessID;
params.ProcessDescription = ProcessDescription;
params.ProcessName = ProcessName;
$.ajax({
type: "POST",
url: 'Process.aspx/updateAProcess',
data: JSON.stringify(params),
...