How to let an ASMX file output JSON

Question

I created an ASMX file with a code behind file  It s working fine  but it is outputting XML   However  I need it to output JSON  The ResponseFormat configuration doesn t seem to work  My code-behind is    System Web Script Services ScriptService  public class  default   System Web Services WebService        WebMethod       ScriptMethod UseHttpGet   true ResponseFormat   ResponseFormat Json       public string   UserDetails                 return new string      abc    def

User · Answer

A quick gotcha that I learned the hard way (basically spending 4 hours on Google), you can use PageMethods in your ASPX file to return JSON (with the [ScriptMethod()] marker) for a static method, however if you decide to move your static methods to an asmx file, it cannot be a static method.

Also, you need to tell the web service Content-Type: application/json in order to get JSON back from the call (I'm using jQuery and the 3 Mistakes To Avoid When Using jQuery article was very enlightening - its from the same website mentioned in another answer here).

User · Answer

A quick gotcha that I learned the hard way (basically spending 4 hours on Google), you can use PageMethods in your ASPX file to return JSON (with the [ScriptMethod()] marker) for a static method, however if you decide to move your static methods to an asmx file, it cannot be a static method.

Also, you need to tell the web service Content-Type: application/json in order to get JSON back from the call (I'm using jQuery and the 3 Mistakes To Avoid When Using jQuery article was very enlightening - its from the same website mentioned in another answer here).

User · Answer

From  WebService returns XML even when ResponseFormat set to JSON   Make sure that the request is a POST request  not a GET   Scott Guthrie has a post  explaining why  Though it s written specifically for jQuery  this may also be useful to you  Using jQuery to Consume ASP NET JSON Web Services

User · Answer

This is probably old news by now  but the magic seems to be     ScriptService  attribute on web service class  ScriptMethod UseHttpGet   true  ResponseFormat   ResponseFormat Json   on method Content-type  application json in request   With those pieces in place  a GET request is successful   For a HTTP POST    ScriptMethod UseHttpGet   false  ResponseFormat   ResponseFormat Json   on method   and on the client side  assuming your webmethod is called MethodName  and it takes a single parameter called searchString              ajax               url   MyWebService asmx MethodName               type   POST               contentType   application json               data  JSON stringify   searchString  q                 success  function  response                                                 error  function  jqXHR  textStatus  errorThrown                    alert textStatus          jqXHR responseText

User · Answer

Are you calling the web service from client script or on the server side   You may find sending a content type header to the server will help  e g     application json  charset utf-8   On the client side  I use prototype client side library and there is a contentType parameter when making an Ajax call where you can specify this  I think jQuery has a getJSON method

User · Answer

Are you calling the web service from client script or on the server side   You may find sending a content type header to the server will help  e g     application json  charset utf-8   On the client side  I use prototype client side library and there is a contentType parameter when making an Ajax call where you can specify this  I think jQuery has a getJSON method

User · Answer

A quick gotcha that I learned the hard way (basically spending 4 hours on Google), you can use PageMethods in your ASPX file to return JSON (with the [ScriptMethod()] marker) for a static method, however if you decide to move your static methods to an asmx file, it cannot be a static method.

Also, you need to tell the web service Content-Type: application/json in order to get JSON back from the call (I'm using jQuery and the 3 Mistakes To Avoid When Using jQuery article was very enlightening - its from the same website mentioned in another answer here).

User · Answer

Alternative  Use a generic HTTP handler   ashx  and use your favorite json library to manually serialize and deserialize your JSON     I ve found that complete control over the handling of a request and generating a response beats anything else  NET offers for simple  RESTful web services

User · Answer

A quick gotcha that I learned the hard way (basically spending 4 hours on Google), you can use PageMethods in your ASPX file to return JSON (with the [ScriptMethod()] marker) for a static method, however if you decide to move your static methods to an asmx file, it cannot be a static method.

Also, you need to tell the web service Content-Type: application/json in order to get JSON back from the call (I'm using jQuery and the 3 Mistakes To Avoid When Using jQuery article was very enlightening - its from the same website mentioned in another answer here).

User · Answer

Alternative  Use a generic HTTP handler   ashx  and use your favorite json library to manually serialize and deserialize your JSON     I ve found that complete control over the handling of a request and generating a response beats anything else  NET offers for simple  RESTful web services

User · Answer

To receive a pure JSON string  without it being wrapped into an XML  you have to write the JSON string directly to the HttpResponse and change the WebMethod return type to void        System Web Script Services ScriptService      public class WebServiceClass   System Web Services WebService            WebMethod          public void WebMethodName                         HttpContext Current Response Write   property  value

User · Answer

From  WebService returns XML even when ResponseFormat set to JSON   Make sure that the request is a POST request  not a GET   Scott Guthrie has a post  explaining why  Though it s written specifically for jQuery  this may also be useful to you  Using jQuery to Consume ASP NET JSON Web Services

User · Answer

From  WebService returns XML even when ResponseFormat set to JSON   Make sure that the request is a POST request  not a GET   Scott Guthrie has a post  explaining why  Though it s written specifically for jQuery  this may also be useful to you  Using jQuery to Consume ASP NET JSON Web Services

User · Answer

This is probably old news by now  but the magic seems to be     ScriptService  attribute on web service class  ScriptMethod UseHttpGet   true  ResponseFormat   ResponseFormat Json   on method Content-type  application json in request   With those pieces in place  a GET request is successful   For a HTTP POST    ScriptMethod UseHttpGet   false  ResponseFormat   ResponseFormat Json   on method   and on the client side  assuming your webmethod is called MethodName  and it takes a single parameter called searchString              ajax               url   MyWebService asmx MethodName               type   POST               contentType   application json               data  JSON stringify   searchString  q                 success  function  response                                                 error  function  jqXHR  textStatus  errorThrown                    alert textStatus          jqXHR responseText

User · Answer

To receive a pure JSON string  without it being wrapped into an XML  you have to write the JSON string directly to the HttpResponse and change the WebMethod return type to void        System Web Script Services ScriptService      public class WebServiceClass   System Web Services WebService            WebMethod          public void WebMethodName                         HttpContext Current Response Write   property  value

User · Answer

Are you calling the web service from client script or on the server side   You may find sending a content type header to the server will help  e g     application json  charset utf-8   On the client side  I use prototype client side library and there is a contentType parameter when making an Ajax call where you can specify this  I think jQuery has a getJSON method

User · Answer

Are you calling the web service from client script or on the server side   You may find sending a content type header to the server will help  e g     application json  charset utf-8   On the client side  I use prototype client side library and there is a contentType parameter when making an Ajax call where you can specify this  I think jQuery has a getJSON method

User · Answer

From  WebService returns XML even when ResponseFormat set to JSON   Make sure that the request is a POST request  not a GET   Scott Guthrie has a post  explaining why  Though it s written specifically for jQuery  this may also be useful to you  Using jQuery to Consume ASP NET JSON Web Services

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