Programming with .NET - General

Re: How to make this just return an xml string (not even call a web service)?

fatihpiristine — Wed, 01 Apr 2009 20:46:30 GMT

is it happening when you closing the browser window? if yes, on browser exit, it disposes everything before it exists.

i can suggest you to do one thing to try this out, run your solution with firefox, from firebug modify silverlight object position property to absolute,

it will exit and run the application again, if you are not getting this error, then it is related to browser window.

Re: How to make this just return an xml string (not even call a web service)?

kobruleht — Wed, 01 Apr 2009 15:01:10 GMT

I tried to call it at application exit event handler using

AjaxCall.MakeCall("Stockservice.asmx", "Logout");

but got InvalidOperationException at line

XMLHttpRequest.Invoke("open", Method.ToUpper(), Url, false);

How to fix ?

Andrus.

System.InvalidOperationException was unhandled by user code
Message="Invalid argument."
StackTrace:
       at System.Windows.Browser.ScriptObject.Invoke(String name, Object[] args)
       at SyncCall.AjaxCall.MakeCall(String Url, String Method)
       at AWSilverlightLOB.App.Application_Exit(Object sender, EventArgs e)
       at System.Windows.CoreInvokeHandler.InvokeEventHandler(Int32 typeIndex, Delegate handlerDelegate, Object sender, Object args)
       at MS.Internal.JoltHelper.FireEvent(IntPtr unmanagedObj, IntPtr unmanagedObjArgs, Int32 argsTypeIndex, String eventName)
InnerException:

Re: How to make this just return an xml string (not even call a web service)?

samcov — Wed, 21 Jan 2009 07:09:27 GMT

This appears to only be able to do a "GET", request, and not a "POST".

Re: How to make this just return an xml string (not even call a web service)?

fatihpiristine — Wed, 21 Jan 2009 00:01:20 GMT

I have modified the code to make it work with ie6, ie5.5 etc. here is the code.
have test on IE6, IE7, FF2, FF3, Opera and Safari. worked fine.
you may need clientaccesspolicy.xml link: http://msdn.microsoft.com/en-us/library/cc197955(VS.95).aspx

namespace SyncCall
{
    public class AjaxCall
    {
        protected static System.Windows.Browser.ScriptObject XMLHttpRequest;
        protected static System.String Result = System.String.Empty;
        /// <summary>
        /// Makes XMLHttpRequest
        /// </summary>
        /// <param name="Url">relative or absolute url as string</param>
        /// <param name="Method">GET or POST</param>
        public static void MakeCall(string Url, string Method)
        {
            // Backward compat
            System.Windows.Browser.HtmlPage.Window.Eval("if(typeof XMLHttpRequest==\"undefined\"){XMLHttpRequest=function(){var a=[\"Microsoft.XMLHTTP\",\"MSXML2.XMLHTTP\",\"MSXML2.XMLHTTP.3.0\",\"Msxml3.XMLHTTP\"];for(var b=0;b<a.length;b++){try{return new ActiveXObject(a[ b ]);}catch(ex){}}};}");
            // create the instance
            XMLHttpRequest = System.Windows.Browser.HtmlPage.Window.CreateInstance("XMLHttpRequest");
            // request data from server
            XMLHttpRequest.Invoke("open", Method.ToUpper(), Url, false);
            // send. !!! do not replace it with "null" as it throws exception
            XMLHttpRequest.Invoke("send", "");
            // get result as string. as gecko based browsers does not return xml
            Result = XMLHttpRequest.GetProperty("responseText").ToString();
        }
        /// <summary>
        /// Returns result from request as string
        /// </summary>
        public static System.String GetResult()
        {
            return Result.ToString();
        }
    }
}

Re: How to make this just return an xml string (not even call a web service)?

samcov — Tue, 20 Jan 2009 23:46:51 GMT

Could you format that better, or attach a project?

Sam...

Re: How to make this just return an xml string (not even call a web service)?

fatihpiristine — Tue, 20 Jan 2009 23:36:32 GMT

code is below

Re: How to make this just return an xml string (not even call a web service)?

vchoudhary — Thu, 01 May 2008 10:06:10 GMT

If I want to use this code in an application that uses cross domain policies,then what changes should I make in the code so that the code works properly.

Or is there any other method by which the same error gets removed in application that uses cross domain policies

Re: How to make this just return an xml string (not even call a web service)?

jackbond — Mon, 17 Mar 2008 20:44:17 GMT

Psychlist1972:
it should be said that this doesn't support some of new things in SL2 like cross-domain policies or anything MSFT does with secure service calls in the future.

Unfortunate, but true. I developed this code because there was no way to call a web service during application exit. I actually hope in the next beta, or sometime before RTM this code becomes entirely irrelevant. I fear however that this code is going to get a lot of usage.

Re: How to make this just return an xml string (not even call a web service)?

Psychlist1972 — Mon, 17 Mar 2008 14:21:46 GMT

Very nicely done. :)

For other folks who may stumble on this code in the future, though, it should be said that this doesn't support some of new things in SL2 like cross-domain policies or anything MSFT does with secure service calls in the future. Often not a deal-killer, but useful to know.

Pete

Re: How to make this just return an xml string (not even call a web service)?

timstallc — Mon, 17 Mar 2008 14:14:23 GMT

Yes! Works perfectly in both. I also love how clean and simple it now is.

Thanks so much

Re: How to make this just return an xml string (not even call a web service)?

jackbond — Mon, 17 Mar 2008 04:16:28 GMT

Tim, I think you are going to be VERY happy when you run this code:

public static string DownloadXmlStringSync(string url)

{

ScriptObject request;
request = HtmlPage.Window.CreateInstance("XMLHttpRequest");
request.Invoke("open", "GET", url, false);
request.Invoke("send", "");
return (string)request.GetProperty("responseText");

}

As for why it worked for some people and not others: Firebug has its own observer effect

Re: How to make this just return an xml string (not even call a web service)?

mchlSync — Mon, 17 Mar 2008 01:58:21 GMT

I used this wrapper for communicating with Astoria from Silverlight (You can read it here.) Some said that they are having the problem..

I get the following error when deleting or updating

An exception of type ‘System.ArgumentException’ occurred in System.Windows.Browser.dll but was not handled in user code

Additional information: [ScriptObject_TypeDoesNotExist]
Arguments:XMLHttpRequest
Debugging resource strings are unavailable. Often the key and arguments provide sufficient information to diagnose the problem. See http://go.microsoft.com/fwlink/?linkid=106663&Version=8.0.30226.2&File=System.Windows.Browser.dll&Key=ScriptObject_TypeDoesNotExist

I can’t retrieve the data too, error on this line
_xmlHttpRequest = HtmlPage.Window.CreateInstance(”XMLHttpRequest”);

{System.ArgumentException: [ScriptObject_TypeDoesNotExist]
Arguments:XMLHttpRequest
Debugging resource strings are unavailable. Often the key and arguments provide sufficient information to diagnose the problem. See http://go.microsoft.com/fwlink/?linkid=106663&Version=8.0.30226.2&File=System.Windows.Browser.dll&Key=ScriptObject_TypeDoesNotExist
Parameter name: typeName
at System.Windows.Browser.HtmlWindow.CreateInstance(String typeName, Object[] args)
at SL2Astoria.XMLHttpRequestWrapper.DoPost(Uri url, String httpVerb, String param)
at SL2Astoria.XMLHttpRequestWrapper.DoPost(Uri url, String httpVerb)
at SL2Astoria.Page.retrieveButton_Click(Object sender, RoutedEventArgs e)}

Actually, I mentioned three operations (Insert, delete and retrieve) in that article. that guy is having some problems in deleting. I'm not sure why. It is working on my machine..

Re: How to make this just return an xml string (not even call a web service)?

jackbond — Sun, 16 Mar 2008 22:08:07 GMT

Hi Tim,

I've got so many dev environments, that I got mixed up which version of Firefox I was running. It is actually working on Firefox 2.0.0.12 for me with the following code:

public static string DownloadXmlStringSync(string url)

{

ScriptObject request;

request = HtmlPage.Window.CreateInstance("XMLHttpRequest");

request.Invoke("open", "GET", url, false);

request.Invoke("send");

return (string)request.GetProperty("responseText");

}

Are you able to set a breakpoint on the server to see if the request is actually making it through?

Re: How to make this just return an xml string (not even call a web service)?

timstallc — Sun, 16 Mar 2008 18:50:57 GMT

Thanks for the new code. It works great in IE, but still no luck in FireFox 2.0.

It fails again on the same like:

request.Invoke("send");

Similar error:

[ScriptObject_InvokeFailed]\r\nArguments:\r\nDebugging resource strings are unavailable

I see what you're trying to do, and it makes sense (calling XmlHttpRequest, similar to what ajax does in a browser), but still no luck on FF 2.0. Is there anything else I can provide to shed some light?

Thanks,

Re: How to make this just return an xml string (not even call a web service)?

jackbond — Sun, 16 Mar 2008 04:19:13 GMT

Try this:

ScriptObject request;

ScriptObject dom;

try

{

request = HtmlPage.Window.CreateInstance("XMLHttpRequest");

request.Invoke("open", "GET", url, false);

request.Invoke("send");

dom = (ScriptObject) request.GetProperty("responseXML");

return (string)dom.GetProperty("xml");

}

catch (Exception ex)

{

throw;

}