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Hi everyone,
I am trying to create a single instance application. What I have been able to do so far is to prevent more than one instance of the application to run (I have used a Mutex). However, what I would like to do is to bring the already running application to the foreground whenever someone is trying to run another instance of the application. In other words, if I already have an instance of the application running, and I try to run the executable again, I would like to see the running application pop up in front of me.
Here is the code that I have so far:
static class Program
{
///
/// The main entry point for the application.
///
[STAThread]
static void Main()
{
// These variables will be used to provide single instance functionality
bool blnExclusive = false; // must be initialized
Mutex SingleInstanceMutex = null; // must be initialized
// Try to create mutex
try
{
SingleInstanceMutex = new Mutex(true, "My Mutex", out blnExclusive);
}
// Catch exception and exit application
catch
{
Application.Exit();
}
// If no other instances exist, start new application
if (blnExclusive)
{
Application.EnableVisualStyles();
Application.SetCompatibleTextRenderingDefault(false);
Application.Run(new myFrm());
GC.KeepAlive(SingleInstanceMutex);
}
else
{
//TODO: try to bring existing instance to foreground
}
}
}
Any help is appreciated, thanks.
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:-DI have been investigating Threads and their usage.
Is there anyplace (book or blog, etc.) where I can find basic information
about setting them up and controllng them.
I tried the C# examples at Microsoft, I would like something that gives more examples of usage-from basic to intermediate.
Thanks for any help.
Al
adolph.evangelista@ge.com
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Try looking at the Articles on www.codeproject.com
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Hi,
How could i highlight the selected row till i select the next row of the datagrid in c#
Thanks in advance
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Hi All,
I have a requirement in which i need to make a web request and store the response in an excel file. I was able to do the whole thing, but the problem is that the thread which creates the Excel File(Excel.exe), stays alive.
Please help me, I create the Excel Application using, Excel Object Library Version 11.
Also I need to show a message in a label box stating the status, something "Processing request N of X...", but the label box doesn't show until the whole process completes...
Thanx in advance,
Joe.
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Joe,
Are you closing the file and quitting Excel when you're done? Unless you do, the Excel process will stick around forever. There's also an option somewhere in the Excel API to let you scavenge an already-running excel.exe process. Just be careful using that -- if you have a UI open, you run that, then you forcibly exit through code, the UI you opened will magically disappear.
As far as the status message, how are you updating it? What's the event that's causing the update? How are you writing it? Are you being careful not to update the UI from anywhere other than the UI thread (you should never do that)? Is your Excel thread blocking?
Show us some code, maybe we can help.
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Hi YoungJoe,
Try using following for quitting excel and cleaning up.
You need to call this method for all your excel objects (worksheet, workbook, etc...)
System.Runtime.InteropServices.Marshal.ReleaseComObject (yourObj);
Hope, this helps
Sincerely,
Elina
Life is great!!!
Enjoy every moment of it! 
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Hello,
I have an application where i need to select a data from and XML file and assign this data to a variable. I would like to create a kinda .ini or .cfg file where the next time the user uses the application it automatically load the previous choice so that the user doesn't need to reselect that same data. of course if a different data is needed then it should overwrite the xml.ini file which only contains the selected XML data.
Any suggestion? Thank you
Donkaiser
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You can use XmlSerialization to save all your data into a xml file. Just look at MSDN.
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To extend that a bit further, you may look into a DataSet or typed DataSet as an option. Basically, you get an OO interface in code, but you can use the ReadXml and WriteXml methods to serialize it to disk with very little code.
If you're using VS.NET, add a new object of type DataSet to your project, fiddle with the schema until all of your configuration information is represented, right-click and go to "Run Custom Tool," then instantiate one in your project.
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Hi guys,
Do you know about a way to convert html into xml. I've seen codeproject's examples but they leave tags open, and everytime I intented to convert it to xml I get an error...
Does anyone of you know how to?
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Hi,
You can try this:
HTML TO XML
It's free.
Eran Aharonovich (eran.aharonovich@gmail.com )
Noviway
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hello,
i'm using c# to create a windows app. i would like to validate the contents of a text box to make sure it is a floating point number. does anybody know how to use regular expressions to accomplish this? i've never used them before...
here's what i have so far:
private void startValBox_Validating(object sender, CancelEventArgs e)
{
if (Regex.IsMatch(startValBox.Text, "regular expression goes here"))
{
startVal = System.Convert.ToDouble(startValBox.Text);
errorMsg.Hide();
//return true;
}
else
{
errorMsg.Text = "The start value is invalid.";
errorMsg.Show();
//return false;
}
}
thanks for your help!
rc
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Are you sure you need a regex? Won't double.TryParse() do the job?
regards
modified 12-Sep-18 21:01pm.
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Double.TryParse() did the trick. I'm still quite new to all this stuff, so I had no idea about that function. Definitely better than trying to use regular expressions.
Thank You!
rc
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You're welcome 
modified 12-Sep-18 21:01pm.
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While regular expressions are a nice choice and the code looks right, why not just Double.Parse() and catch the exception?
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Controling program flow with exceptions is bad practice!
Exceptions for exceptional behaviour - the user typing an invalid value is not exceptional, it's expected.
In this case the framework (v2.0) provides the TryParse for exactly this scenario.
Current blacklist
svmilky - Extremely rude | FeRtoll - Rude personal emails | ironstrike1 - Rude & Obnoxious behaviour
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Though you can use regular expressions, the TryParse would be a bit quicker. Feed it the value in the textbox and if it returns true then all is good. The regular expression would be the "show-off" route and the boss or project lead may or may not be impressed.
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I agree with your statement, within reason. If you want to parse a date, you don't want to have to write a regular expression for every possible accepted date format. TryParse is a nice addition indeed, but in 1.1, I'd much rather take the exception.
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