如何在WEB.API中显示自定义错误JSON结果

Question

I'M new to Web.API . I've the URL

http://localhost:21923/communities/getPost/locationID=1 .

If suppose, by mistake i used location instead of locationID in the above URL it showing Error . Instead of that i need to return the following JSON Result.

 { "message": "Parameter missmatch", "errorCode": 404 (or) something else, "Status": false } 

How can is show that JSON result instead of that pre-defined error in Web.API?

Answer 1

Try using Application_Error handler in Global.asax: https://msdn.microsoft.com/en-us/library/24395wz3.aspx

void Application_Error(object sender, EventArgs e)
{
  // Code that runs when an unhandled error occurs

  // Get the exception object.
  Exception exc = Server.GetLastError();

  // Handle HTTP errors by sending the JSON (only for Http Error)
  if (exc.GetType() == typeof(HttpException))
  {
    // The Complete Error Handling Example generates
    // some errors using URLs with "NoCatch" in them;
    // ignore these here to simulate what would happen
    // if a global.asax handler were not implemented.
      if (exc.Message.Contains("NoCatch") || exc.Message.Contains("maxUrlLength"))
      return;

    //Return a JSON object
    Response.Write(JsonConvert.SerializeObject(new
    {
        "message": "Parameter missmatch",
        "errorCode": "404 (or) something else",
        "Status": false
    })
    );
  }

  // For other kinds of errors give the user some information
  // but stay on the default page
  Response.Write("<h2>Global Page Error</h2>\n");
  Response.Write(
      "<p>" + exc.Message + "</p>\n");
  Response.Write("Return to the <a href='Default.aspx'>" +
      "Default Page</a>\n");

  // Log the exception and notify system operators
  ExceptionUtility.LogException(exc, "DefaultPage");
  ExceptionUtility.NotifySystemOps(exc);

  // Clear the error from the server
  Server.ClearError();
}