As of ASP.NET 3.5, all AJAX responses from ASP.NET Web Services are enclosed inside a d object.
This is the case with all ASMX services JSON serialized through the
ASP.NET AJAX Extensions in ASP.NET 3.5. Even if you’re only returning
a scalar return value, such as a string, int, or boolean, the result
will always be enclosed within the “d”.
http://encosia.com/a-breaking-change-between-versions-of-aspnet-ajax/
Therefore with pre-3.5 applications you'd do the following:
success(data)
{
var value = data;
}
With 3.5+ you must do:
success(data)
{
var value = data.d;
}
I've got an application which is ran on post-3.5 and pre-3.5.
How can I keep my code consistent for these applications?
Also this would be useful so that I don't have to change the code in the pre-3.5 applications when they are upgraded.
you could have a little helper function:
function GiveMeMyDamnData(data){
if(data.d)
return data.d;
return data;
}
then...
success(data)
{
var value = GiveMeMyDamnData(data);
}
...just need to make sure you never use a 'd' property in the AJAX response (else that will get confusing!
Related
I have developed a WCF in ASP.NET 4.5 with a couple of simple methods. One such method has a return type of bool (written in c#). When I add this service to my ASP.NET 4.5 web application as a Service Reference, it works as expected in the code behind. It also works the same way in a .NET 4.5 C# Console application. Below is the code in the Implementation file for this method:
public bool AddADUser(string a, string b)
{
bool done = false;
return done;
}
When I call it from my programs, it looks like this:
static void Main(string[] args)
{
var proxy = new ServiceReference1.ADServiceClient();
proxy.Open();
try
{
Console.WriteLine(proxy.HelloWorld());
bool success = proxy.AddADUser("testA", "testB");
Console.WriteLine(success.ToString());
}
catch (Exception ex)
{
Console.WriteLine(ex.Message);
Console.WriteLine(ex.InnerException);
}
finally
{
proxy.Close();
}
}
This is how it works in my ASP.NET 4.5 / C# app, and my C# .NET 4.5 Console App.
When I add this as a "Web Reference" to an existing ASP.NET 2.0 / VB.NET app, it does something different. The command to call the AddADUser() function is all of a sudden requiring 4 parameters:
AddADUser(a As String, b As String, ByRef AddADUserResult As Boolean, ByRef AddADUserResultSpecified As Boolean)
Why are these parameters being added -- is this something with VB.NET not allowing this to actually return a boolean, or a web reference not being able to return a boolean, or a problem with this being ASP.NET 2.0 ?
Or do I need to make a custom DataContract? I have that part left out of my Interface, just relying on defaults. Do I need to specify XmlSerializer somewhere also to be able to use this? It appears to actually do what it is supposed to, and I just can't figure out why there are two booleans and which one is the one I want.
This page gives a long explanation about it and a weird workaround that I didn't feel like doing:
http://www.codeproject.com/Articles/323097/WCF-ASMX-Interoperability-Removing-the-Annoying-xx
What I wound up doing was adding
[OperationContract, XmlSerializerFormat(Style = OperationFormatStyle.Rpc)]
to my methods and I also added
[ServiceContract,XmlSerializerFormat]
to my interface attribute and now they act like I would expect.
Reference: http://www.wenda.io/questions/1191041/result-and-resultspecified-parameters-in-wcf-service.html
I wish to populate a JavaScript array with the results of a database query. From what I understand, a good approach is to populate a bunch of directories on my server with serialized XML or JSON files which my JS functions can then read into without having to access the database. Is this true? Should the database write these XML files upon user interaction, or should they be prepopulated?
From the details you have provided:
I Personally would create a Web Service endpoint returning your linq query serialized to JSON using JSON.NET or an equivalent. The endpoint can then be called using ajax within your client page.
You can check this example out on ASP.NET for how to create a asmx (legacy) web service. Also you can look at this example of using the [WebMethod] attribute .
A web method in your code behind files.
[WebMethod]
[ScriptMethod(ResponseFormat = ResponseFormat.Json)]
public string GetMyQueryResultsAsJson()
{
var results = GetQueryResults();
var jss = new JavaScriptSerializer();
string json = jss.Serialize(results);
return json;
}
A ajax call on your client page:
function loadData() {
var myArray = [];
$.getJSON("<%= ResolveUrl("~/MyPage.aspx/GetMyQueryResultsAsJson") %>", function (data) {
$.each(data, function(obj) {
myArray.push([obj.id, obj.someValue, obj.AnotherValue]);
});
});
}
I used jQuery ajax with generic http handler returing json
I created handler and put my business logic there.
It return me the result in form of json
I iterated the json using jquery.
And created my html form that.
Edit 1
Here are some useful links
http://www.codeproject.com/Articles/203621/Call-HTTPhandler-from-jQuery-Pass-data-and-retriev
http://www.sharepointnutsandbolts.com/2010/11/sp2010-ajax-part-4-returning-json-from.html
Edit 2
You can also take benefit of jtemplate
http://www.joe-stevens.com/2010/01/05/using-the-jtemplate-jquery-plugin-with-ajax-and-asp-net/
http://encosia.com/use-jquery-and-aspnet-ajax-to-build-a-client-side-repeater/
I use code below to read AssemblyTitle attribute of .NET apps, unfortunately Assembly.GetEntryAssembly() always return Null in ASP.NET app. How to read AssemblyTitle in ASP.NET app?
public static string Title
{
get
{
var attributes = Assembly.GetEntryAssembly().GetCustomAttributes(typeof(AssemblyTitleAttribute), false);
if (attributes.Length > 0)
{
var titleAttribute = (AssemblyTitleAttribute)attributes[0];
if (titleAttribute.Title.Length > 0)
return titleAttribute.Title;
}
return System.IO.Path.GetFileNameWithoutExtension(Assembly.GetEntryAssembly().CodeBase);
}
}
You must have a type that you know is defined in the same assembly that contains the AssemblyTitle. Then you can do:
typeof(MyType).Assembly.GetCustomAttributes
Note that (for what I know) there isn't any other bulletproof method.
For example using HttpContext.Current doesn't work if you want to do it not during a web request (so you can do it on response of a user action, but not from a separate thread, or from a static initializer, or from global.asax)
Some similar readings (full of half successes):
GetEntryAssembly for web applications
Using the Web Application version number from an assembly (ASP.NET/C#)
I use the following in asp.net web app:
if (ApplicationDeployment.IsNetworkDeployed)
return ApplicationDeployment.CurrentDeployment.CurrentVersion.ToString();
return System.Reflection.Assembly.GetExecutingAssembly().GetName().Version.ToString();
Edit: Sorry, thats just the version, not the title! I combined your version and mine:
System.Reflection.Assembly.GetExecutingAssembly().GetCustomAttributes(typeof(AssemblyTitleAttribute), false);
That gets the assembly title attribute just fine. The difference is in GetExecutingAssembly() versus your GetEntryAssembly().
So, there are a wealth of Flex articles online about how to handle a .NET WebMethod that returns a DataSet or DataTable. Here is an example:
Handling web service results that contain .NET DataSets or DataTables
So, I know how to use result.Tables.<tablename>.Rows and the like. But what I cannot seem to figure out or find online is how to go the other direction - a method to pass objects or tables back to the .NET Webservice from Flex, without stooping to passing XML as a string, or making huge web service methods that have one parameter for each property/column of the object being stored. Surely others, smarter than I, have tackled this issue.
I am using ASP.NET 2.0 Typed DataSets, and it would be really nice if I could just pass one object or array of objects from Flex to the web service, populate my Typed DataTable, and do an Update() through the corresponding typed TableAdapter. My dream would be a [WebMethod] something like one of these:
public void SaveObject(TypedDataTable objToSave) { ... }
public void SaveObject(TypedDataSet objToSave) { ... }
I've had the typed datatables saving to the database, I know how to do that part and even a few tricks, but we had XML being passed back-and-forth as a string - eww. I'm trying to get to a more object-based approach.
The best object based approach is AMF. I assume its probably a bit late in your your development cycle to change your integration layer, but otherwise I dont know of a way to get around marshalling your object(s) back into XML or separating them out into their primitive components.
For .NET implementations of AMF check out:
FlourineFX(FOSS)
WebORB for .NET
Its amazing how easy things become once AMF is used, for example using the Mate MVC framework and an AMF call passing a complex object to the server looks something like this:
<mate:RemoteObjectInvoker instance="yourWebservice" method="saveComplexObject" showBusyCursor="true" >
<mate:resultHandlers>
<mate:CallBack method="saveComplexObjectSuccess" arguments="{[resultObject]}" />
</mate:resultHandlers>
<mate:faultHandlers>
<mate:MethodInvoker generator="{DataManager}" method="presentFault" arguments="{fault}" />
</mate:faultHandlers>
</mate:RemoteObjectInvoker>
With result and fault handlers being optional.
The direction I ended up going was close to what I hoped was possible, but is "hack-ish" enough that I would consider SuperSaiyen's suggestion to use AMF/ORM a better solution for new/greenfield projects.
For sake of example/discussion, let's say I am working with a Person table in a database, and have a typed DataSet called PeopleDataSet that has PersonTableAdapter and PersonDataTable with it.
READ would look like this in .NET web service:
[WebMethod]
public PeopleDataSet.PersonDataTable GetAllPeople() {
var adapter = new PersonTableAdapter();
return adapter.GetData();
}
... which in Flex would give you a result Object that you can use like this:
// FLEX (AS3)
something.dataProvider = result.Tables.Person.Rows;
Check out the link I put in the question for more details on how Flex handles that.
CREATE/UPDATE - This is the part I had to figure out, and why I asked this question. The Flex first this time:
// FLEX (AS3)
var person:Object = {
PersonID: -1, // -1 for CREATE, actual ID for UPDATE
FirstName: "John",
LastName: "Smith",
BirthDate: "07/19/1983",
CreationDate: "1997-07-16T19:20+01:00" // need W3C DTF for Date WITH Time
};
_pplWebSvcInstance.SavePerson(person); // do the web method call
(For handling those W3C datetimes, see How to parse an ISO formatted date in Flex (AS3)?)
On the .NET web service side then, the trick was figuring out the correct Type on the web method's parameter. If you go with just Object, then step into a call with a debugger, you'll see .NET figures it is a XmlNode[]. Here is what I figured out to do:
[WebMethod]
public int SavePerson(PeopleDataSet p) {
// Now 'p' will be a PeopleDataSet with a Table called 'p' that has our data
// row(s) (just row, in this case) as string columns in random order.
// It WILL NOT WORK to use PeopleDataSet.PersonDataTable as the type for the
// parameter, that will always result in an empty table. That is why the
// LoadFlexDataTable utility method below is necessary.
var adapter = new PersonTableAdapter();
var tbl = new PeopleDataSet.PersonDataTable();
tbl.LoadFlexDataTable(p.Tables[0]); // see below
// the rest of this might be familiar territory for working with DataSets
PeopleDataSet.PersonRow row = tbl.FirstOrDefault();
if (row != null) {
if (row.PersonID > 0) { // doing UPDATE
row.AcceptChanges();
row.SetModified();
}
else { // doing CREATE
row.CreationDate = DateTime.UtcNow; // set defaults here
row.IsDeleted = false;
}
adapter.Update(row); // database call
return row.PersonID;
}
return -1;
}
Now, the kluge utility method you saw called above. I did it as extension method, that is optional:
// for getting the Un-Typed datatable Flex gives us into our Typed DataTable
public static void LoadFlexDataTable(this DataTable tbl, DataTable flexDataTable)
{
tbl.BeginLoadData();
tbl.Load(flexDataTable.CreateDataReader(), LoadOption.OverwriteChanges);
tbl.EndLoadData();
// Probably a bug, but all of the ampersand (&) in string columns will be
// unecessarily escaped (&) - kluge to fix it.
foreach (DataRow row in tbl.Rows)
{
row.SetAdded(); // default to "Added" state for each row
foreach (DataColumn col in tbl.Columns) // fix & to & on string columns
{
if (col.DataType == typeof(String) && !row.IsNull(col))
row[col] = (row[col] as string).Replace("&", "&");
}
}
}
If I use jQuery AJAX to call a specific ASP.NET page method how to have that method return a value back to the AJAX method that called it?
Update
My situation is I have an existing web application with many existing methods. I would like to be able to use jQuery to execute some of these methods and then update the UI with the results. My mandate is to stay away from ASP.NET AJAX and stick with jQuery. Management is concerned about continued development and support with ASP.NET AJAX from Microsoft. I agree with them.
You can use JQuery with page methods this way: http://encosia.com/2008/05/29/using-jquery-to-directly-call-aspnet-ajax-page-methods/
The success callback contains a parameter with the returning data.
HTH.
There are two ways to skin this cat (that I am familiar with).
The ".Net Way" which involves a Web Method and a Script Manager (see here: http://geekswithblogs.net/frankw/archive/2008/03/13/asp.net-ajax-callbacks-to-web-methods-in-aspx-pages.aspx).
The "Old Skool Way" which involves simply writing a response out by determining what was called. Typically you'd use a framework like MVC so going to http://www.MyWebsite.com/Object/Method/Id can map back to Object.Method(id).
You can do this without a framework like MVC but it makes things a little more difficult and, if you go that route, you should really use an ASP.Net handler rather than an actual page (since you don't need the Aspx overhead). This is an Ashx file.
With pure ASP.NET (not talking WCF here) I'd go with a handler (ASHX) file, and use JSON as the interchange format. I won't get into the details of JSON (here is a decent start), but the idea is a lightweight handler on the server that generates json text and returns it to the client, which can then use the structure easily in javascript.
This is obviously a simplified example but the gist is the JSON can be data driven from the server and easily consumed by the javascript on the client.
server:
<%# WebHandler Language="C#" Class="Handler" %>
using System;
using System.Web;
public class Handler : IHttpHandler {
public void ProcessRequest (HttpContext context) {
context.Response.ContentType = "text/json";
context.Response.WriteFile("~/myData.json");
}
public bool IsReusable {
get {
return false;
}
}
}
client:
myData =
(function ()
{
var json = null;
$.ajax({
'async': false,
'global': false,
'url': "handler.ashx",
'dataType': "json",
'success': function (data) {
// this code is called when the
// data is returned from the server
json = data;
}
});
return json;
}
)();
alert(myData.MyArray[0].MyProperty);