当我尝试使用 jquery ajax 从 '.asmx' 网络服务获取数据时，如何调试“500 内部错误”

Question

我正在尝试使用 jquery 向我的 asp.net 服务器发送 ajax 请求并获取一些数据 back.But 我无法做到这一点 seems.No 不管我做什么我都会得到 Failed to load resource: the server responded with a status of 500 (Internal Server Error) 错误 massege.I 知道这是一个重复的问题，但我几乎阅读了我在 Whosebug 和其他网站上可以阅读的所有内容，并且 none解决方案有帮助 me.I 我正在尝试调试这个东西并弄清楚我能做什么，但我不知道我必须怎么做

这是我的代码：

这是 ajax 调用：

$(document).ready(function () {
    $('.list-item button').on('click', function () {
        $.ajax({
            type: "POST", //HTTP method
            url: "/WebServices/RequestHandler.asmx/HelloWorld", 
            contentType: "application/json; charset=utf-8",
            dataType: "json",
            data: "{}",
            success: function (msg) {               
            console.log(msg);
            },
            error: function (xhr, textStatus, thrownerror) {
            alert("something went wrong");
            console.log(xhr.status);
            console.log(xhr.responseText);
            console.log(thrownerror);
            }
        });
    });
});

这是我的网络服务：

[WebService(Namespace = "http://tempuri.org/")]
    [WebServiceBinding(ConformsTo = WsiProfiles.BasicProfile1_1)]
    [System.ComponentModel.ToolboxItem(false)]
    // To allow this Web Service to be called from script, using ASP.NET AJAX, uncomment the following line. 
    [System.Web.Script.Services.ScriptService]
    public class RequestHandler : System.Web.Services.WebService
    {
        private string connectionString = ConfigurationManager.ConnectionStrings["connection"].ConnectionString;

        [WebMethod]
        public static string HelloWorld()
        {
            return "hello";
        }
    }

如您所见，这是一个非常简单的方法，我只是想弄清楚发生了什么以及为什么它不起作用

是的，我确实省略了这两部分：

contentType: "application/json; charset=utf-8",
dataType: "json",

到处都建议了数千次，但根本没有帮助。

还有在浏览器控制台中触发错误消息时的代码：

<!DOCTYPE html>
<html>
    <head>
        <title>Request format is unrecognized for URL unexpectedly ending in '/HelloWorld'.</title>
        <meta name="viewport" content="width=device-width" />
        <style>
         body {font-family:"Verdana";font-weight:normal;font-size: .7em;color:black;} 
         p {font-family:"Verdana";font-weight:normal;color:black;margin-top: -5px}
         b {font-family:"Verdana";font-weight:bold;color:black;margin-top: -5px}
         H1 { font-family:"Verdana";font-weight:normal;font-size:18pt;color:red }
         H2 { font-family:"Verdana";font-weight:normal;font-size:14pt;color:maroon }
         pre {font-family:"Consolas","Lucida Console",Monospace;font-size:11pt;margin:0;padding:0.5em;line-height:14pt}
         .marker {font-weight: bold; color: black;text-decoration: none;}
         .version {color: gray;}
         .error {margin-bottom: 10px;}
         .expandable { text-decoration:underline; font-weight:bold; color:navy; cursor:hand; }
         @media screen and (max-width: 639px) {
          pre { width: 440px; overflow: auto; white-space: pre-wrap; word-wrap: break-word; }
         }
         @media screen and (max-width: 479px) {
          pre { width: 280px; }
         }
        </style>
    </head>

    <body bgcolor="white">

            <span><H1>Server Error in '/' Application.<hr width=100% size=1 color=silver></H1>

            <h2> <i>Request format is unrecognized for URL unexpectedly ending in '/HelloWorld'.</i> </h2></span>

            <font face="Arial, Helvetica, Geneva, SunSans-Regular, sans-serif ">

            <b> Description: </b>An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code.

            <br><br>

            <b> Exception Details: </b>System.InvalidOperationException: Request format is unrecognized for URL unexpectedly ending in '/HelloWorld'.<br><br>

            <b>Source Error:</b> <br><br>

            <table width=100% bgcolor="#ffffcc">
               <tr>
                  <td>
                      <code>

An unhandled exception was generated during the execution of the current web request. Information regarding the origin and location of the exception can be identified using the exception stack trace below.</code>

                  </td>
               </tr>
            </table>

            <br>

            <b>Stack Trace:</b> <br><br>

            <table width=100% bgcolor="#ffffcc">
               <tr>
                  <td>
                      <code><pre>

[InvalidOperationException: Request format is unrecognized for URL unexpectedly ending in &#39;/HelloWorld&#39;.]
   System.Web.Services.Protocols.WebServiceHandlerFactory.CoreGetHandler(Type type, HttpContext context, HttpRequest request, HttpResponse response) +489329
   System.Web.Services.Protocols.WebServiceHandlerFactory.GetHandler(HttpContext context, String verb, String url, String filePath) +212
   System.Web.Script.Services.ScriptHandlerFactory.GetHandler(HttpContext context, String requestType, String url, String pathTranslated) +47
   System.Web.MaterializeHandlerExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute() +346
   System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean&amp; completedSynchronously) +155
</pre></code>

                  </td>
               </tr>
            </table>

            <br>

            <hr width=100% size=1 color=silver>

            <b>Version Information:</b>&nbsp;Microsoft .NET Framework Version:4.0.30319; ASP.NET Version:4.0.30319.18408

            </font>

    </body>
</html>
<!-- 
[InvalidOperationException]: Request format is unrecognized for URL unexpectedly ending in &#39;/HelloWorld&#39;.
   at System.Web.Services.Protocols.WebServiceHandlerFactory.CoreGetHandler(Type type, HttpContext context, HttpRequest request, HttpResponse response)
   at System.Web.Services.Protocols.WebServiceHandlerFactory.GetHandler(HttpContext context, String verb, String url, String filePath)
   at System.Web.Script.Services.ScriptHandlerFactory.GetHandler(HttpContext context, String requestType, String url, String pathTranslated)
   at System.Web.HttpApplication.MaterializeHandlerExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute()
   at System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously)
-->

从上面的错误消息中我可以理解，url 有问题，它不是 "FORMATTED CORRECTLY" 之类的，我真的不知道我能做些什么来解决这个错误.

如有任何想法，我们将不胜感激

提前致谢

更新我还在某处读到默认情况下禁用 GET 和 POST 请求，因此我还将这些协议添加到我的 Web.config 文件中：

<configuration>
    <system.web>
    <webServices>
        <protocols>
            <add name="HttpGet"/>
            <add name="HttpPost"/>
        </protocols>
    </webServices>
    </system.web>
</configuration>

但我还是遇到了同样的问题

Answer 1

如果您想使用 GET 调用您的 WebMethod，您需要添加一个 ScriptMethod 属性以允许它：

[WebMethod]
[ScriptMethod(UseHttpGet=true)]
public static string HelloWorld()
{
    return "hello";
}

来自documentation：

If a method is not marked with ScriptMethodAttribute, the method will be called by using the HTTP POST command and the response will be serialized as JSON

或者，使用 POST 访问 WebMethod。

Answer 2

好的，所以我终于弄明白了，事实证明，这是我的 .net 的问题 framework.I 使用本教程重新安装了我机器上安装的 .net 框架，重新启动了我的电脑，省略了我的 webmethod 的 static 声明，现在一切正常

当我尝试使用 jquery ajax 从 '.asmx' 网络服务获取数据时，如何调试“500 内部错误”

How do I debug the "500 internal error" when I am trying to get data form '.asmx' webservice using jquery ajax

jquery

asp.net

ajax

web-services

asmx