CacheItemRemovedCallback Problems - .NET (Core and Framework) Discussion Boards

Thanks for your help everyone. I am going to have to upgrade to Pro.

I am not a top-notch super programmer, simply a high school student finishing his last year before going off to Univeristy. I have a working knowledge of MFC, and have wrote a few custom apps for my school board. I still have ALOT to learn (I dont know COM/ATL/etc), but .NET seems to be the buzz-word of the day. I have read up on it, and various posts here, and on the microsoft website and various other resources, but I still have a big question mark over my head - "whats the point? why?".

The main problem is, I cant seem to wrap my head around a situation in which using .NET would be best, and how it would be done, and why.

So, lets take my current project for example. All I need to do, is pretty much make up a basic front end to a database that lets two people add/edit/modify, generate a report/search/printout information relating to applicants for a job. Not all that fancy, and the way I am approaching it now (not using .NET/etc) is working just fine. I made the program before, but wasnt happy with how it turned out, so I am simply re-doing it from scratch.

In reality, this will only be used by 2 users, 3 max at a single time, and the demands are rather low. But for the sake of example, could someone explain how I could use .NET with this application? (3 or so clients accessing a centralized database on a seperate server), and what benifits I would have in doing so?

Or any application of .NET, ie: purpose of the application, why .NET, what advantages does .NET give? With it being Microsoft, it is pretty much follow the leader or get left behind, and I'd much rather not get trampled and out-dated before leaving the safe walls of highschool by not keeping up with the times.

An example I see off the top of my head would have the centralized server hosting a remoting component which a thin-client would tie into. All the thin-client would need is the .NET runtime, and a bit of code to glue together the remoting components and the UI.

All of the real code would be running on the server.

Then you put up a .NET enabled website where you tie into those same components and just re-create the UI. And then you offer some webservices so other companies/just yourself can use an internet enabled program to tie into the database as well.

Thats how I see it anyway Smile | :)

James

Sonork ID: 100.11138 - Hasaki

.NET is a new Microsoft way of making server-side apps, especially web-services. If you are interested in server-side programming for Windows, this is the way to go.

I vote pro drink Beer | [beer]

I wish that would have come to mind when I wrote my reply; a lot less typing and much clearer. Big Grin | :-D

James

Sonork ID: 100.11138 - Hasaki

Thanks for the reply (both who replied). Helps (sorta) clear things up, far more then the 10 page long articles that I have sorted though trying to make heads and tails of things.

I was wondering if you knew of an example that I could find that made a web-service that for example, would query a database (or anything), and how to make a web client in VC++ to access/make use of that service? Or point me to a resource where I can find out how.

VC++ is what I am most familiar with. Not looking for a "code it for me", but just a spot to look in the right direction, I was fiddling around with some examples, but as I dont know C# or ASP, and most of the examples are relating to them, I was sorta flounding.

Now that I have a better idea, I think I have an idea of how to make use of .NET for some side projects of mine that I have been playing with.

Thanks again.

Hello;

I'm in trouble with .NET framework. I want to build and browse a new created empty aspx page. I'm getting following message;

Server Error in '/myaspx' Application.
--------------------------------------------------------------------------
Parser Error
Description: An error occurred during the parsing of a resource required to service this request. Please review the following specific parse error details and modify your source file appropriately.

Parser Error Message: The 'Inherits' attribute is not supported by the 'application' directive.

Source Error:

Line 1: <%@ Application Codebehind="Global.asax.vb" Inherits="myaspx.Global" %>

Source File: c:\inetpub\wwwroot\myaspx\global.asax Line: 1

--------------------------------------------------------------------------Version Information: Runtime Build:1.0.2914.16; ASP.NET Build:1.0.2914.16

How can i solve that problem. Anybody help me?

Thank you...

Ahmet Orkun GEDiK

Guys,

I am having problems with the use of the CacheItemRemovedCallback event within an ASP.NET/C# website I am building. The below code is from my global.aspx file. The code loads XML/XSL objects into the Cache for later use. I also create a Cache dependency so should any files change which my XML/XSL objects use, the Cache is updated automatically. The code works only when something is removed from the Cache by another aspx file, since the code correctly identifies the HttpContext. However, when one of my files is changed and the RemovedCallback() function is fired, for some reason the Context and the HttpContext are both null. As such my code never has a chance to update the Cache again. Rather it exists "without an error" as soon as I try to use Cache.Insert. Does anyone know if this is a bug in Beta 2, or am I missing something, like the use of a special Context object?

Any help greatly appreciated..........

Cheers,
Tim.

<%@ Import Namespace="System.Xml.Xsl" %>
<%@ Import Namespace="System.Xml.XPath" %>
<%@ Import Namespace="System.Web.Caching" %>
<%@ Import Namespace="CommerceEngine.Common" %>

private static CacheItemRemovedCallback onRemove = null;
private XPathDocument CommerceListXmlObj;
private XslTransform CommerceListXslObj;

public void Application_OnStart()
{
ApplicationConfiguration.OnApplicationStart(Context.Server.MapPath( Context.Request.ApplicationPath ));
onRemove = new CacheItemRemovedCallback(this.RemovedCallback);

CommerceListXmlObj = new XPathDocument(CommerceEngineConfiguration.CommerceListXmlFilePath);
HttpContext.Current.Cache.Insert("CommerceListXmlObj", CommerceListXmlObj, new CacheDependency (CommerceEngineConfiguration.CommerceListXmlFilePath), DateTime.Now.AddHours(1), TimeSpan.Zero, CacheItemPriority.Default, CacheItemPriorityDecay.Slow, onRemove );

CommerceListXslObj = new XslTransform();
CommerceListXslObj.Load(CommerceEngineConfiguration.CommerceListXslFilePath);
HttpContext.Current.Cache.Insert("CommerceListXslObj", CommerceListXslObj, new CacheDependency(CommerceEngineConfiguration.CommerceListXslFilePath), DateTime.Now.AddHours(1), TimeSpan.Zero, CacheItemPriority.Default, CacheItemPriorityDecay.Slow, onRemove );
}

public void RemovedCallback(String k, Object v, CacheItemRemovedReason r)
{
switch(k)
{
case "CommerceListXmlObj" :

CommerceListXmlObj = new XPathDocument(CommerceEngineConfiguration.CommerceListXmlFilePath);
HttpContext.Current.Cache.Insert("CommerceListXmlObj", CommerceListXmlObj, new CacheDependency(CommerceEngineConfiguration.CommerceListXmlFilePath), DateTime.Now.AddHours(1), TimeSpan.Zero, CacheItemPriority.Default, CacheItemPriorityDecay.Slow, onRemove );
break;
}
}

Hi folks,

Lately I have been spending some time attempting to get my head around ASP.NET. One on the exercises I have set myself is to build a modest little website. But I have run into a few design problems that I hope some one can help me with.

I have decided to have a standard header to each page. (Just like code project has the standard header at the top of this page.) In pure ASP I would have had these as a SSI (eg .

In ASP.NET this still works but when I attempt to add make the header a bit smarter by making it a WebForm things get all confused. This happens because they are each seperate pages with seperate C# code behind them. Which means there is two <@ Page ...> directives. Which means it doesn't work!

What is the proper design pattern/model to acheive this type of behaviour?
I hope this makes sense to you all...

Matt
------
Accept that some days you are the pigeon and some days the statue.

I think the ASP.NET way would be to create a new server control encapsulating the header.

A lot more info on doing such a thing can be gleaned from the IBuySpy set of websites.

HTH,

James

Sonork ID: 100.11138 - Hasaki

thanks for the tip. I am having a look at ibuyspy right now!

Matt
------
Accept that some days you are the pigeon and some days the statue.

There are 2 choices, you could compile your own control into a dll, or you could make a UserControl file, with an ascx extension.

Judging by the fact that you are making a header, i'm betting you want to make a UserControl, which is much like the old asp include file, except much much cooler.

here's the msdn docs on UserControls, ( watch for wrapping )
http://msdn.microsoft.com/library/?url=/library/en-us/cpref/html/cpref_start.asp?frame=true

Thanks for the help. Much appreciated. I am experimenting with them at the moment.

Smile | :)

Matt
------
Accept that some days you are the pigeon and some days the statue.

Matt,
You can make that header two ways.
1.) make it a Web User Control and then on any page you want that headret you simply insert your header user control.

You also could implement the Application BeginRequest event in the global.asax file.
Like this and emit a header without having to explicitly add it to each page.

Sub Application_BeginRequest(sender As Object, e As EventArgs)

' emit page header
Context.Response.Write("<html>" + ControlChars.Lf + _
"<body bgcolor=#efefef>" + ControlChars.Lf + "<hr>" + _ ControlChars.Lf)

End Sub

Good Luck,
Martin Garins

Hello;

I'm in trouble with .NET framework when i want to build and browse a new created empty aspx page. I'm getting following message;

Server Error in '/myaspx' Application.
-----------------------------------------------------------------------------
Parser Error
Description: An error occurred during the parsing of a resource required to service this request. Please review the following specific parse error details and modify your source file appropriately.

Parser Error Message: The 'Inherits' attribute is not supported by the 'application' directive.

Source Error:

Line 1: <%@ Application Codebehind="Global.asax.vb" Inherits="myaspx.Global" %>

Source File: c:\inetpub\wwwroot\myaspx\global.asax Line: 1

-----------------------------------------------------------------------------Version Information: Runtime Build:1.0.2914.16; ASP.NET Build:1.0.2914.16

How can i solve that problem. Anybody help me?

Thank you...

Here is my question in all its simplicity:

WHAT THE HECK IS .NET????????

I have searched the whole frigging net and all ive found is so jargon that means absolutly nothing. I have even gone to the trouble of getting .NET Server Beta 3 just to see and there is nothing new.

Please tell me i'm not the only one who is thinking this! Mad | :mad:

.NET or not .NET? MFC is the question......

.NET Defined

// Fazlul

Get RadVC today! Play RAD in VC++
http://www.capitolsoft.com

Is there a way to define an assignment operator on a managed C++ class?
I tried using the C# syntax, but that doesn't seem to want to work...
What I've got (that isn't working) is something like this:

public __gc class ATTRIB
{
ATTRIB();
ATTRIB(const ATTRIB* a);
virtual ~ATTRIB();

static implicit operator ATTRIB(ATTRIB* a) { return new ATTRIB(a); }
}

Is it possible to create a single file NET assembly from C# and MC++?
I wrote MC++ class that is a sort of proxy for ASPI API. The rest of the program is written in C++.
I'd preffer single-file than multi-file assembly. Is it doable?
CK

correction: the rest of the program is of course written in C# nor C++

I have a class that has been written in plain C++ that makes calls into
a library that exports many functions that take char array parameters.
What I want to know is how I can get / convert the data in a .NET String
object into a plain char array so that I can pass the value into
the function call? Basically any help converting the new .NET types into
older style "unsafe" types would be helpful. Thanks.

You can use one of two things, either the StringBuilder or you can marshal the string data.

If you need a buffer of some sort, like you need for getting a special folder you need to use StringBuilder

Code courtesy Tomas Restrepo

[ DllImport("shell32.dll") ]
private static extern bool SHGetSpecialFolderPath(IntPtr hwndOwner, StringBuilder lpszPath, int nFolder, bool fCreate);

StringBuilder dirPath = new StringBuilder(256,1024);
bool res = SHGetSpecialFolderPath(IntPtr.Zero, dirPath, CSIDL_APPDATA, true);

If you just need to pass a string in to a function but do not modify it use marshalling. I don't know what will happen if you try to modify it, it could reflect the change, or it could blow up on you.

From Inside C# by Tom Archer

[DllImport("user32.dll", CharSet=CharSet.Unicode)]
static extern int MessageBox(
		IntPtr hWnd, 
		[MarshalAs(UnmanagedType.LPWStr)]
		string msg,
		[MarshalAs(UnmanagerType.LPWStr)]
		string caption,
		int type
);

MessageBox(0, "Hello, World!", "This is called from a C# app!", 0);

Both code snippets are untested, but should demonstrate how to do it. I made a minor change in Tom Archer's code and that was to reflect that handles, such as HWNDs should be IntPtr's instead of int's.

HTH,

James

Sonork ID: 100.11138 - Hasaki
and a digital cookie (not chocolate chip, its computer chip) goes to whoever can be the first to tell me what Hasaki means. I know someone registered on here can tell me Smile | :)

Thanks for the good information... but is there a way I can convert to an unsafe type BEFORE actually passing the data into a function?

If I've got a String* or Stringbuilder* in Managed C++ and want to convert it into an
unmanged type like char* or LPStr, how is that possible?

-dvryce

Can't say I know how.

I haven't looked at MC++ too much, only because I don't have any old code I have to work with that would warrant MC++ to me.

Perhaps the DOTNET mailing list could be of some help? Its been a great resource for myself and many others. It is a high volume mailing list though so you'll probably want to subscribe to the digest version, or use the web-based interface.

Sorry I couldn't be of more help,

James

Sonork ID: 100.11138 - Hasaki
and a digital cookie (not chocolate chip, its computer chip) goes to whoever can be the first to tell me what Hasaki means. I know someone registered on here can tell me Smile | :)

Hi all,

I have an MFC App.
I'm trying to port it to MC++.

For starters, I'm just trung to port one single View.
When i give __gc , the compiler spews out errors.

macros, DECLARE_MESSAGE_MAP, et al are not MC++ compliant!

So, what do i do now?

I don't want to make this a COM Componenet & use P/Invoke.
I want to change my app to MC++.

What do you guys suggest? I port everything to WinForms?
Man, I have many CFormView , & CDialog's! It would take like eons to do that Dead | X|

PLEASE help guys/gals! any suggestions?

In Anticipation..........