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I've never worked with multithreading before in any language.
I'm trying to figure out how to do the following:
I have a function, which generates unique values based on the current time.
It saves the data to a log file.
I have it set that when I click a button, it executes this code.
Rather, what I need to happen is to have it continually execute the function every 60 seconds until I reclick the same button.
I assume I need to use threads to do this. I've looked up several tutorials, but I really can't find an example to do this.
Can someone give me an idea?
Thanks.
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... this is the function I have. The first if clause needs to start a thread which executes the SaveWindow function every 60 seconds. The second needs to terminate the thread. I don't even know if this is the way threads work.
private void buttonScraperControl_Click(object sender, EventArgs e)
{
if (buttonScraperControl.Text == "Start")
{
buttonScraperControl.Text = "Stop";
SaveWindow(); // EXECUTE THIS FUNCTION EVERY 60 SECONDS
}
else if (buttonScraperControl.Text == "Stop")
{
buttonScraperControl.Text = "Start";
// STOP FROM EXECUTING EVERY 60 SECONDS
}
}
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I believe you can use the built in "Timer" control. http://www.c-sharpcorner.com/controls/timer.asp
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Will the timer stop execution of other parts of the program?
There are several other things that the user will be doing while
this bit of code is executing.
Is a timer really the correct solution?
Thanks!
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If you use a timer, it will be using a single thread. That means that the timer will only be triggered when your program is not busy doing anything else.
If you use a separate thread, it will be running even if your program is busy. The drawback is that the code has to be thread safe, meaning that if you are using any variables from both threads, you will have to take special precausions to make sure that only one thread at a time is using the variables.
---
b { font-weight: normal; }
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The System.Form.Timer or whatever it is, for some reason deson't lock up your GUI. Someone once explained why to me...
/\ |_ E X E GG
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I think a timer would be a good solution for your problem, cause it was made to execute code in regular intervals. Now you have to select the right timer for your needs.
If you use the System.Windows.Forms.Timer, your code will be executed in the UI thread. This prevents you from paying attention to threading issues, but if the code is time-consuming it will hang your GUI, cause the UI thread is busy.
If you use System.Timers.Timer or the System.Threading.Timer, your code will be executed by a worker thread. This won't affect your GUI, but you have to pay attention to threading issues e.g. change of GUI controls.
Take a look at this site[^] on MSDN for some more information.
www.troschuetz.de
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Hi,
I would like to create a winform application using c#, that looks kind of like Adobe Photoshop. That means the main window will have some small dockable windows inside the main window (those dockable windows can be minimized, closed, or maximized and docked). These windows will have other controls inside them.
I was wondering if you can give me some pointers on how to create windows like that, or can you send me links to some custom controls that I can use in my code that behave like those windows.
I'm still using visual studio.NET 2003, I might switch to VS.NET 2005 if there are controls like that in VS2005. Any idea, pointer, links, codes will be much appreciated.
Thanks
Ben
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What you are describing is MDI forms. Try looking here: http://www.codeproject.com/csharp/mdiformstutorial.asp
-- modified at 18:00 Thursday 13th October, 2005 (typo'd)
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Not really. I want the forms to be dockable too.
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Did you know that the Form class derives from Control? Think about that. A Form can be used just like a control. All it takes is a couple of modifications to it's properties. Check out this[^] article on MSDN for more information.
RageInTheMachine9532
"...a pungent, ghastly, stinky piece of cheese!" -- The Roaming Gnome
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I am working on a program to display "flash cards." Basically, the flash cards are 2 jpeg files, the front and the back. I'm using them to aid in learning a foreign language. Currently, I have this code:
private void btAdd_Click(object sender, EventArgs e)<br />
{<br />
hpClass blah = new hpClass();<br />
blah.addToArray( tbFrontFile.Text, tbBackFile.Text );<br />
blah.serializeArray( blah, "test.txt" );<br />
}<br />
[Serializable]<br />
public class hpClass<br />
{<br />
Stream[,] images;<br />
FileStream fsFront;<br />
FileStream fsBack;<br />
FileStream fsData;<br />
<br />
BinaryFormatter bfSerial;<br />
<br />
public void addToArray(string front, string back)<br />
{<br />
fsFront = new FileStream( front, FileMode.Open );<br />
fsBack = new FileStream( back, FileMode.Open );<br />
<br />
images = new Stream[1, 2]<br />
{<br />
{ fsFront, fsBack }<br />
};<br />
}<br />
<br />
public void serializeArray(object anything, string path)<br />
{<br />
fsData = new FileStream( path, FileMode.Create );<br />
bfSerial = new BinaryFormatter();<br />
bfSerial.Serialize( fsData, anything );<br />
fsData.Close();<br />
}<br />
}
The error I am getting is this:
Type 'System.IO.FileStream' in Assembly 'mscorlib, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089' is not marked as serializable.
And the bfSerial.Serialize line is the one generating the error. I'm using the C# 2005 Express Edition Beta. I'm completely lost  Any suggestions?
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Every member of your class needs to be serializable or marked with [NonSerialized]. You cannot serialize streams, so they'll need the [NonSerialized] attribute for sure. If you really want your object to contain the binary content of all those files, you should read the data into byte array members probably. However, that sounds clunky, especially if the jpg files are right there, all your object needs to remember is their names, right? Let me know if I'm not understanding your question right.
Matt Gerrans
-- modified at 17:26 Thursday 13th October, 2005
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Actually, I plan to use the file that is outputted as flashcard sets. Meaning it should contain all the information as the original jpegs and also on how to display them. This way, I won't have to distribute (to my friends) hundreds of jpeg files which could get moved, deleted, etc. This is why I wanted to stream the contents of the jpeg file into an array, and then save the array to a file.ext. I didn't realize you couldn't serialize streams :p So I guess I would have to dump the data into a byte array. You're right, it does sound a little clunky. I was thinking of using zip files, but then they wouldn't necesarrily come out in the right pairs (front and back.) This is the only other option I could think of.
Thanks for your input 
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Hi
I have a general question regarding validation of an objects attributes. I am working on a web application and involved in developing the business layer code. Given the fact that I am relatively new to web development, I had this question: Do I do the validation of the object's attributes before doing any action in the business layer? For example, if I have an user class in my business layer with 5 attributes, and some methods like select, delete, insert, update etc which are instance methods. So, before inserting the actual user into the database, do I need to write validation code in the insertmethod to see if the 5 attributes are not null? I am not sure if this needs to be done at the presentation layer or the business layer.
Any comments please?
Thanks
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Probably you should have your validations on three levels. Each has its own purpose:
1. Validate on the user interface, to provide a speedy answer to the user, and to avoid hitting the server unnecessarily. This may not include all the validations, only those that are quick and simple to do on the UI layer.
2. Validate on the business rules layer, to enforce the business rules. This includes all rules, with the possible exception of referential integrity, that can be delegated to the database server. Here you can call any method and do the most complicated validations.
3. Validate on the database server. The objective is to enforce a minimum sanity on the data, like required fields and referential integrity. Theoretically all validation could be done here, using constraints, stored procedures and triggers, but I think it is more productive to use Visual Studio for coding logic. If you can be sure all database access will be through your code, you can keep the validation at this level simple. Anyway, this layer of validation is a safety net.
Good luck.
Fernando Correia
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I've been searching around for an easy way of saving a formatted RTF box as an html file. I found a DLL that costs 250 bucks... but I'm sure there's an easier (cheaper) solution out there...
anyone got any advice? 
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I don't know any good solution, but I wrote a (very simple) RTF to HTML converter a while back. It doesn't support images or table or anything like that, only plain formatting.
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what about colors and fonts and everything?
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There are several RTF-to-HTML converters on the web if you're willing to spend a few hundred dollars.
Tech, life, family, faith: Give me a visit.
I'm currently blogging about: Cops & Robbers
Judah Himango
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I am creating an ASP.Net web application using C#. In one of my page, I need to load a list of a thousand names to be display in a DataGrid table. The table has 3 columns, a first name column, last name column, and a third column containing a delete link. The table can be sorted by first name or last name. When EnableViewState is set to true, it takes up to 1 minute to load the info into the DataGrid and display the table. When I set EnableViewState to false, it takes about 15 seconds to load the table, but I cannot sort the table anymore. I have set breakpoint in my sort command code, but it never gets hit when I click the first or last name link to sort the table. Setting a breakpoint in the IniatializeComponent show that the sort event was triggered, but my sort code is never called. I have no idea what's going on and would appreciate any help.
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Please don't double post.
---
b { font-weight: normal; }
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How do you access jpgs bitmaps and icons in a resource file?
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I have a previous post here[^] that might help.
Enjoy.
The most exciting phrase to hear in science, the one that heralds the most discoveries, is not 'Eureka!' ('I found it!') but 'That's funny...’
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