Call ServerSide function from JS using PageMethods in ASP.NET AJAX

Question

0.00/5 (No votes)

See more:

When I execute this code (inside .js) :

jQuery.fn.stickyNotes.createNote = function () {
        var pos_x = 0;
        var pos_y = 0;
        var note_id = jQuery.fn.stickyNotes.notes.length + 1; 
  PageMethods.saveNote(note_id); // remote method

I need to save note_id value inside MSSQL database.

I put this on default.aspx (inside <body> I'm not sure if I'm right), to enable AJAX:

<pre lang="xml"><form id="form2" runat="server">
<asp:ScriptManager ID="ScriptManager1" runat="server"></asp:ScriptManager>
</form>

and for a method in default.aspx.cs

[System.Web.Services.WebMethod]
    public static string saveNote(int note_id)
    {
if (note_id == null || text.Length == 0)
            return String.Empty;
        SqlConnection conn = null;
        try
        {
            string connection = ConfigurationManager.ConnectionStrings["ConnectionString"].ConnectionString;
            conn = new SqlConnection(connection);
            string sql = "INSERT INTO .....";
            SqlCommand cmd = new SqlCommand(sql, conn);
            cmd.Parameters.AddWithValue("ID_Note", note_id);
            // ...
            conn.Open();
            string contNm = Convert.ToString(cmd.ExecuteScalar());
            return contNm;

I have this defined on <head>
<script type="text/javascript" src="script/jquery.stickynotes.js"></script>

By now I have two importante questions:

- I still didnt compiled the code because I get the error that I have two forms with runat=server (I another one two login). How can I solve this problem? Can I put the script manager inside that form?

- If I do that my AJAX dont work. When I click add note nothing happens... previosly it works (it creates a new note/element). If I comment this line PageMethods.saveNote(note_id); it works again... It looks like that my JS stops working. Can you help me please ?

Thanks in advance.

Posted 21-Dec-10 6:00am

Maxdd 7

Updated 21-Dec-10 6:30am

v9

Add a Solution

1 solution

Add a Solution

Add your solution here

Treat my content as plain text, not as HTML

Preview 0

…

Existing Members

Sign in to your account

...or Join us

Download, Vote, Comment, Publish.

Your Email
Password
Forgot your password?

Your Email
This email is in use. Do you need your password?
Optional Password

I have read and agree to the Terms of Service and Privacy Policy
Please subscribe me to the CodeProject newsletters

When answering a question please:

Read the question carefully.
Understand that English isn't everyone's first language so be lenient of bad spelling and grammar.
If a question is poorly phrased then either ask for clarification, ignore it, or edit the question and fix the problem. Insults are not welcome.
Don't tell someone to read the manual. Chances are they have and don't get it. Provide an answer or move on to the next question.

Let's work to help developers, not make them feel stupid.

This content, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)

AspDotNetDev · Accepted Answer · 2010-12-21T06:47:00

Solution 1

You need to set EnablePageMethods:

HTML

<%@ Page Language="C#" %>
<script runat="server">
    [System.Web.Services.WebMethod]
    public static string GetHello()
    {
        return "Hello";
    }
</script>
<html>
<head runat="server">
    <title>Test PageMethods</title>
</head>
<body>
    <script type="text/javascript">
        function DoIt() {
            PageMethods.GetHello(function(result) {
                alert(result);
            });
        }
    </script>
    <form id="form1" runat="server">
        <asp:ScriptManager runat="server" EnablePageMethods="true" />
        <input type="button" onclick="DoIt();" value="Do Stuff" />
    </form>
    <form id="form2"></form>
</body>
</html>

Posted 21-Dec-10 6:47am

AspDotNetDev

Comments

Maxdd 7 21-Dec-10 13:08pm

Thanks, that's a stupid mistake from me.

However I think the function public static string saveNote(int note_id) its not working - executing.

I have the code I posted exactly like that "INSERT INTO..."; I dont even have the DB created, and I get any error, so that means it's not reaching that code.

What am I missing?

AspDotNetDev 21-Dec-10 13:14pm

I believe you have to create a callback function to handle successes and failures... exceptions might just get swallowed otherwise. Copy my code exactly, because I ran it and confirmed it works. Then try pasing your insert code into the server-side function (using some dummy value since you won't be passing a note_id parameter). Then add the node_id parameter. Break the problem into pieces and you should be able to solve it. I also noted you have a try/catch, but you didn't show all the code, so I don't know how you're handling the exception... you might just be swallowing it.

Maxdd 7 21-Dec-10 13:24pm

Well I thing the problem is my default.aspx.cs for some reason is not even working.

I placed

protected void Page_Load(object sender, EventArgs e)
{
string strConn;
strConn = System.Web.Configuration.WebConfigurationManager.ConnectionStrings["ConnectionString1"].ConnectionString;
System.Data.SqlClient.SqlConnection Conn = new System.Data.SqlClient.SqlConnection(strConn);
Conn.Open();
}

as I dont even have a connection string (web.config) and I didnt get any error. - what is happening? so strange..

Maxdd 7 21-Dec-10 13:31pm

Well, its working now (the .cs). So strange.

Time to create the DB and see if the AJAX its working.

Thanks for your help!

AspDotNetDev 21-Dec-10 13:38pm

You are welcome. If my answer helped you, please remember you can vote on answers and you can "accept" them.

AspDotNetDev 21-Dec-10 14:16pm

It shouldn't matter how the function gets reached. And try something simple, like writing to a text file on your local file system, rather than writing to a DB and expecting an exception which may get suppressed. And user alerts in your JS to be sure your code is being reached. And remember that PageMethods don't return anything... you need to use callbacks to get results: http://aspalliance.com/1922_PageMethods_In_ASPNET_AJAX.2

AspDotNetDev 21-Dec-10 14:16pm

Also, I think breakpoints will still work in your PageMethod (though that might require the full version of Visual Studio... not sure).

Maxdd 7 21-Dec-10 14:34pm

Really thanks for helping you are really helping me understanding this. But still there's something left.

I did exactly as you told me to do:

In my.cs I have

[System.Web.Services.WebMethod]
public static string GetHello()
{
return "Hello";
}

[System.Web.Services.WebMethod]
public static int saveNote()
{

TextWriter tw = new StreamWriter("date.txt");
tw.WriteLine(DateTime.Now);
tw.Close();
return 0;
}

and in my .js:

function DoIt() {

alert("HERE do IT!");
jQuery.fn.stickyNotes.createNote();
PageMethods.saveNote();

PageMethods.GetHello(function(result) {
alert(result);
});
}

Strange thing: I get hello, but I didnt get any file (in page_load that code it works)..

Any other idea ? :(

Maxdd 7 21-Dec-10 14:55pm

<pre lang="cs">[System.Web.Services.WebMethod]
public static string GetHello()
{
TextWriter tw = new StreamWriter("date.txt");
tw.WriteLine(DateTime.Now);
tw.Close();
return "Hell22o";
}

The hell22o just appears if I comment those textwriter lines, and that ones never get executed...

Any more ideas?

AspDotNetDev 21-Dec-10 17:15pm

It is likely the TextWriter code (and the database code) are throwing exceptions and you are never seeing them. Put a try/catch in there... if you catch an exception, return "Darn555" instead of "Hell22o". Or, if you want, return the exception message.

Maxdd 7 21-Dec-10 19:29pm

Thank you so much aspdotnetdev.

I tried:

public static string GetHello()
{

try
{
TextWriter tw = new StreamWriter("date.txt");
tw.WriteLine(DateTime.Now);
tw.Close();
return "Hell22o";

}

catch(Exception e)
{
return "Darn5555"+e;
}

}

I used that and now I'm getting the same exception that I had when I placed that code on page_load.

I always supposed that if I got an exception in page_load (at Visual Studio) I got the same info at a function. Well, I learned with my mistake, and I'm moving forward now.

Thanks again for the patient :)