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Statics are always within the context of an AppDomain, so if your process consists of two or more AppDomains statics will be different.
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Software Design Engineer
Developer Division Sustained Engineering
Microsoft
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Hey Heath!
How's life in the shadow of an actively rumbling volcano? 
I thought he was asking if it was possible to persist a session-specific value using a static, like you've suggested. I did't think that's possible, but I could be wrong? Is the AppDomain session-scoped or application-scoped? Seems like a dumb question, I know. But just for clarification purposes...
Also, just to point out for future readers ... yeah, right! ... using a Static such as this, in either Session or Application scope, does not propogate it's value acrossed multiple servers hosting the same web application. So, if you have two or more web servers running the same application, say for load balancing purposes, all servers will have different values for the Static "global" variable.
RageInTheMachine9532
"...a pungent, ghastly, stinky piece of cheese!" -- The Roaming Gnome
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Dave Kreskowiak wrote:
How's life in the shadow of an actively rumbling volcano?
Exciting! I've been through tornados having been from the midwest, but this is a new experience. I had a lot of interest in volcanoes (and earthquakes) when I was younger (did a fair share more than just "class projects" on them) so this will be fun to see in person. If I get a chance I'll be taking some pics. 
It's not expected to be dangerous to the greater Puget Sound area, though, so I'm not worried.
What is exciting is that I've killed two potentially deadly spiders in our new apartment, all within a week of moving in! While they look like brown recluse spiders, 1) those are only supposed to be in the south-east, and 2) they're often mistaken for hobo spiders, which are in this area (and just as potentially deadly).
Back to the topic at hand...
As far as the problem goes, it really all comes down to AppDomains. A process can have more than one AppDomain, and a web application is an AppDomain. As long as the AppDomain is active, the statics are, well, static. Since an AppDomain cannot span multiple machines, what you said about services is true.
To the original poster, if you want a "global" variable across multiple server or applications, you either need to persist it in some storage medium (like a database, although that can be pretty slow depending on load) or use .NET Remoting which allows communication between multiple AppDomains (through indepedent transport and formatting channels). You could, for example, have a singleton running on some machine and the separate servers communicate with the remoting object through a proxy (which you implement a mutex to lock the increment and/or decrement).
There's lots of different ways to solving the problem.
This posting is provided "AS IS" with no warranties, and confers no rights.
Software Design Engineer
Developer Division Sustained Engineering
Microsoft
[My Articles]
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Heath Stewart wrote:
Exciting! I've been through tornados having been from the midwest, but this is a new experience. I had a lot of interest in volcanoes (and earthquakes) when I was younger (did a fair share more than just "class projects" on them) so this will be fun to see in person. If I get a chance I'll be taking some pics.
Awsome!  I'm so jealous! I've had that same, call it morbid, curiosity about how these things work and still have it to this day.
I've been within 500 feet of a tornado before, BUT COULDN'T SEE IT! because it was heavily rain-wrapped. All we saw, looking through the 8 foot tall plate glass windows in the front of the store  , were roofs being torn off buildings ... what a let-down that was.
I've even had the pleasure of watching empty Coke cans slide back and forth acrossed my desk during earthquakes in and around South-East Michigan. I know, it's not an earthquake mecca and they're weak by Pacific Coast standards, but it's still pretty funny to try and balance on one foot while putting jeans on during an earthquake (1986 - epicenter in middle of Lake Erie).
If Mt St Helens blows again, we want pictures! LOTS of pictures! Setup a webcam if you have to! Who knows if the one at the Johnston Ridge Observatory[^] will be working if/when it does decide to erupt.
and now, back to our show...
--------8<--------------------------
I agree with your assessment of the speed of persisting Session info to an SQL server. It's as flexible a solution as your going to get, but it does tend to be a little slow. I've installed the SQL state server package that comes with, I can't remember which or where, but I think, ASP.NET or Visual Studio .NET Enterprise.
I've thought about both single and multiple server session state caching schemes. A single server solution is easy to implement, but has the downfall of not being scalable to support say, 15 IIS servers.
Mostly, I've wondered what the benefits, limitations and pitfalls are of a solution consisting of small cluster of servers, no more than 3 to start, each running a "Singleton" component, but sync'ing up their data on a real-time basis. These servers could possibly run behind a single-IP solution to facilitate fault-tolerance.
The list of ponderings I've come up with is pretty long... What would be the database synchronization requirements? What would the specification of the synchronation protocol look like? What kind of traffic load would just the synchronization protocol generate? There would probably have to be some kind of mechanism to ensure the consistancy of the state data before the next request comes in on the same session. What would happen if two requests came in on the same session, but the state servers were not able to sync up their data before the second request came in? How would the servers defend themselves against running out of memory since there would be no media to drop the database on? What would the memory requirements be? How would the servers detect a failed server? How would the synchronization protocol handle this situation? How would it handle the reintroduction of a restarted server? ... The list goes on and on...
What if we cahnged the scheme so that each server only holds a portion of the overall database instead of a full copy of it? Start a new list of ponderings...
RageInTheMachine9532
"...a pungent, ghastly, stinky piece of cheese!" -- The Roaming Gnome
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I am using a DataGrid for display purposes only and would like to deactivate much of the default functionality as far as the user clicking on it. I have tried overridding OnMouseDown, but when the user clicks on a cell it still gets selected and goes into input mode. I need to disable this kind of behavior, but I still want to capture mouse events so I cannot really set Enabled = false.
My thought was to cover the client area of the DataGrid with a Panel. However, the Panel would need to be transparent, and I don't know how to do this. Is is possible? Is there a better solution?
Thanks!
Mark Mokris
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Why not bind your DataGrid to a DataView that disables what you don't need? You can do so like this:
DataView view = new DataView(dataSet1.Tables["MyTable"]);
view.AllowDelete = false;
view.AllowEdit = false;
view.AllowNew = false;
dataGrid1.DataSource = view; Using a DataView makes it easier to manage sorting and filtering, although you can still do that when binding to a DataSet or DataTable using the DataSet.DefaultViewManager.
This posting is provided "AS IS" with no warranties, and confers no rights.
Software Design Engineer
Developer Division Sustained Engineering
Microsoft
[My Articles]
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Hi Heath,
Thanks for the response. I had already tried what your saying, but still when the user clicks on a cell, it gets selected and a text cursor appears. You will not be able to type anything, but I'd like to avoid the text cursor appearing.
Does anyone know, is it possible to create a transparent panel?
Thanks,
Mark
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Yes, I do, but that's not the right way to do it and will only be supported on Windows 2000 and newer (for Windows NT platforms). This uses the SetLayeredWindowAttributes native API that you must P/Invoke, something we've discussed in this forum before and which a few articles on this site discuss.
However, there's still better ways. If you just don't want the DataGrid to respond to any user input (at least on cells, which begs the question of why you're even using the DataGrid then when either using a ListView or just drawing the items yourself would be sufficient), then use the DataGrid.HitTest in conjunection with overriding OnMouseDown to make sure that when a user is over a cell you don't call base.OnMouseDown to continue processing the notification message (WM_LBUTTONDOWN). This allows you to maintain the normal mouse message processing for other parts of the DataGrid while maintaining functionality for all supported platforms on which the CLI is implemented.
This posting is provided "AS IS" with no warranties, and confers no rights.
Software Design Engineer
Developer Division Sustained Engineering
Microsoft
[My Articles]
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Is there a control I can add to the textbox that is like the "formatting bar" in Word. I need the user to be able to choose font, color, etc... The question is, do I have to make that panel/bar from scratch or can I import it as a control from anywhere?
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You'll have to either write your own Toolbar code to handle what all the buttons are supposed to do or you can use a commercially available control to handle the Toolbar, still writing the code that does what the buttons say they do.
A Textbox has very few properties that make it useful for editing and formatting like this. Why not use a RichTextBox control instead?
RageInTheMachine9532
"...a pungent, ghastly, stinky piece of cheese!" -- The Roaming Gnome
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What I meant by textbox is RichTextBox, sorry. But is there a control for that or will I still have to write my own?
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A Toolbar is just a collection of buttons and other controls. Clicking the button will fire an event that signals such, but it will not do whatever the button image says on it's own. You have to supply the code to Save, for example, or Save As, or change the Font of the selection and so forth. There is nothing that will do this for you.
RageInTheMachine9532
"...a pungent, ghastly, stinky piece of cheese!" -- The Roaming Gnome
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If a user clicks on a cell in a dataGrid is there any way to return the row number of the cell they clicked (or double clicked) on?
Thanks.
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Hi everyone,
I've been stuck with this problem for several days already. My code extensively uses asynchronous delegate invocation using the Delegate.BeginInvoke method. The general pattern is as follows:
Scheduler or UI thread:
1) BeginInvoke function 1
First function:
1) prepare data
2) BeginInvoke data processing passing CurrentThread (see below)
3) CurrentThread.Suspend
4) (after resume) go to step 1 with new data processing command, if all commands are executed, exit
Data processing:
0) get calling thread (passed in parameters)
1) process data
2) set result
3) resume calling thread
Several data processing commands (Command pattern) require asynchronous calls, too. That is that BeginInvoke method is called from inside another method which was called using BeginInvoke, too. What I've noticed so far is that sometimes the delegate being BeginInvoke'd is NOT CALLED AT ALL! To give more evidence, I have a special Logger class which sends messages to a text box. Apparently, it uses Control.BeginInvoke to correctly dispatch Text property changes. Sometimes again the function specified in MethodInvoker delegate is also NOT CALLED AT ALL!
What could be the problem? I honestly hope it is not a bug in the framework, as the project is (and has been for the last month) in the final stage.
Regards,
Serge (Logic Software, Easy Projects .NET site)
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Serge Lobko-Lobanovsky wrote:
First function:
1) prepare data
2) BeginInvoke data processing passing CurrentThread (see below)
3) CurrentThread.Suspend
4) (after resume) go to step 1 with new data processing command, if all commands are executed, exit
I've got a question. Why are you launching another thread and then pausing the current one, waiting for the newly launched thread to complete? There's no reason to launch another thread to do the work if your just going to sit around and wait for it to complete!
RageInTheMachine9532
"...a pungent, ghastly, stinky piece of cheese!" -- The Roaming Gnome
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You're right. I am now simplifying the code. However, the proble is still there: I call Control.BeginInvoke(new MethodInvoker(myMethod)) and the debugger never stops in myMethod, and the code never executes.
Regards,
Serge (Logic Software, Easy Projects .NET site)
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Hi folks...
I am working with mdi forms and i would like to disable the mdichild to be moved out from the mdicontainer and the scrollbars must not appear. What i am trying to say is that the mdichild form must not be able to be moved out of the parent container. How can i do that?
Sorry my poor english
Thiago
C# beginner - brazil
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My suggestion would be to add handlers to the move and size properties of your child window, and make sure its position stays within the bounds of the parent window
--
Help me! I'm turning into a grapefruit!
Phoenix Paint - back from DPaint's ashes!
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and... how can I do that?
I've never worked with handlers in C#... as I said, i am beginner. Plz, help me! If you want, I can send you the project.
Best reguards
Thiago
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I'm not at a computer with C# on it at the moment, but if memory serves me right, you'll need to bring up the form for the child window in the form editor, then in the properties panel click on a little icon that looks like a bolt of lightning (a yellow zigzag) - click that and it'll show all the possible handlers you can give this form - double click on the move and size ones and it'll make the functions for you
(Anyone else able to give a better description?)
--
Help me! I'm turning into a grapefruit!
Phoenix Paint - back from DPaint's ashes!
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Hello,
i want to ask if image buttons are supported by Smart Device Applications?
thx
regards
pat
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Hello,
i developed a smart device application with a login function. Now i want to develop that after the user presses the login button for approximately 3 seconds a greeting screen is displayed where personal information of the logged in user is displayed and then it is automatically forwarded to the main screen.
Is this possible to develop for a smart device application? if yes can anybody give me a short explanation how it works?
thanks in advance
regards
patrick
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I'm not sure about smart device applications specifically, but the approach I'd try would just be to open up a form with your greeting message displayed, that has a timer attached set to fire after 3 seconds, and have an handler function for that timer that closes the form. Then just create an instance of the greeting form from the constructor (or some suitable place) of your main form, that'll make it get displayed
--
Help me! I'm turning into a grapefruit!
Phoenix Paint - back from DPaint's ashes!
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hi,
I have code to add access control entry to active directory user object so that they can't change password (User cannot change password is checked)
But i wonder it's possible to write code to remove this access control entry again. I have tried using AccessControlList.RemoveAce method..but the "User cannot change password" is still checked.
Using Windows 2003 server active directory and System.DirectoryServices here.
Any help?
Thanks
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