|
Hi
I'm struggling with a strange problem here, I can't set the text of a button in some circumstances.
Here's my code:
private void btnGo_Click(object sender, EventArgs e)
{
try
{
btnGo.Text = "Processing...";
}
catch (...)
finally
{
btnGo.Text = "Start";
}
}
If I remove btnGo.Text = "Start", then the text "Processing" shows up once the long operation has finished.
/edit: I solved it by calling btnGo.Refresh() after btnGo.Text. But why is this necessary, will the button repaint itself only after another Paint-Event occured?
Does anyone know what might be causing this strange behaviour?
regards
modified 12-Sep-18 21:01pm.
|
|
|
|
|
You need to use Asynchronous process using threads
Thanks and Regards
Sandeep
If you want something you never had,
do something you have never done!
|
|
|
|
|
Immediately after settings the button text, just call Application.DoEvents(), so your application gets and processes the message to repaint itself.
Dave Kreskowiak
Microsoft MVP
Visual Developer - Visual Basic
2006, 2007
|
|
|
|
|
There are many ways to do it if any one want to make user wait untill the process completes he can use asyncronous process as back ground thread .
There are n number of articles available on CP .
i know it is very tidious but more effective than Application.DoEvents()
Thanks and Regards
Sandeep
If you want something you never had,
do something you have never done!
|
|
|
|
|
There are also some people who are not ready to start throwing threads around. There are also situations where threading a process isn't acceptable, or would be too much work to keep the user from waiting for 1 or 2 seconds on a simpler process.
He really didn't give any kind of information about what this process was doing. So, to keep his code simple, DoEvents is a very easy fix to the immediate problem. If he wanted to move this process to a background thread, he can ask about that all he wants and we'll help with it.
Dave Kreskowiak
Microsoft MVP
Visual Developer - Visual Basic
2006, 2007
|
|
|
|
|
I'm absolutely familiar with Threads and right after I posted this question I found the solution myself 
I may switch my app to use threads in the future, but it's just a simple app for myself which querys a small database and displays some data, so button.Refresh() will do the job here.
regards
modified 12-Sep-18 21:01pm.
|
|
|
|
|
Greeeg wrote: I'm absolutely familiar with Threads and right after I posted this question I found the solution myself
Great!
Greeeg wrote: it's just a simple app for myself which querys a small database and displays some data,
Hence, the "simple" suggestion. 
Dave Kreskowiak
Microsoft MVP
Visual Developer - Visual Basic
2006, 2007
|
|
|
|
|
May be the process is too fast, so the processing happens in less than second, and the finally line anyway will make it = "Start".
|
|
|
|
|
This is not a strange behavior, your should start a new thread to do the time consuming work and on the finish event of the tread set the btnGo.Text = "Start".
http://stefanprodan.wordpress.com
|
|
|
|
|
HI All
I am confused while using Thread.BeginCriticalRegion(); in my application
what i am trying after compliting specific task by thread i have to abort same thread by calling abort method see the code
<br />
<br />
private void button3_Click(object sender, EventArgs e)<br />
{<br />
ParameterizedThreadStart paramThreadDelagate = new ParameterizedThreadStart(WorkWithParameter);<br />
Thread thread = new Thread(paramThreadDelagate);<br />
thread.Start();<br />
Thread.Sleep(1000); <br />
thread.Abort();<br />
MessageBox.Show("Aborted");<br />
}<br />
<br />
<br />
<br />
<br />
<br />
private void WorkWithParameter()<br />
{<br />
<br />
Thread.BeginCriticalRegion();<br />
MessageBox.Show("1");<br />
MessageBox.Show("2");<br />
MessageBox.Show("3");<br />
MessageBox.Show("4");<br />
MessageBox.Show("5");<br />
Thread.EndCriticalRegion();<br />
}<br />
<br />
The idea behind the critical region is to provide a region of code that must be executed as if it were a single statement. Any attempt to abort a thread while a critical region will have to wait until after the critical region is compplite .so the problem is i am getting message Aborted instead of executing whole WorkWithParameter method. Can any one help me out ?
Thanks and Regards
Sandeep
If you want something you never had,
do something you have never done!
|
|
|
|
|
I'm not sure that BeginCriticalRegion does what you think it does. MSDN[^] says this about the function:
Notifies a host that execution is about to enter a region of code in which the effects of a thread abort or unhandled exception might jeopardize other tasks in the application domain.
It doesn't say anything about multiple lines of code being executed "as if it were a single statement", and doesn't suggest anywhere that it blocks Thread.Abort() from ending the Thread.
|
|
|
|
|
Hi
But it says that Thread.Abort does not make any effect if the current context is in the critical region thats why Dot.NET 2.0 has introduced this and Thread.Suspend and Thread.Resume have been retired
Actually i m reading Microsoft press book name .NET FrameWork 2.0 Application Development Foundation by Tony Northup and many more in that book they mention " The idea behind the crical region is to provide a region of code that must be executed as if it were single statement . Any attempt to abort a thread while it is within a critical region will have to wait until after the critical region is complete ." PAge number 380 Chapter 7 lesson 1 .
Thanks and Regards
Sandeep
If you want something you never had,
do something you have never done!
|
|
|
|
|
Hmm . . . from that text it does sound like BeginCriticalRegion is supposed to create a non-Abortable section of code, but your own test program is showing that it doesn't. When the author uses the phrase "The idea behind the critical region" it makes me wonder exactly what he means - does he mean that the code IS executed as one statement (and is therefore not abortable), or that idealistically .Net tries to make it appear to the CLR that the code being executed is one statement? The answer seems to be shown by your test program.
Check out this[^] post - it asks the same question that you have and Peter Ritchie [C# MVP] has done a good job of answering it.
|
|
|
|
|
Look up "lock" or "Monitor" in your help.
Phil
|
|
|
|
|
Lock and Monitor concept are for mulitythreading Synchronization concept
Which are not different what i asked i think
Thanks and Regards
Sandeep
If you want something you never had,
do something you have never done!
|
|
|
|
|
|
|
Hi,
When are the properties that I set in the properties window used in my application?
I have a class that does som plotting. One property in the class is XMax. XMax is set to 10 in the class but in properties window XMax is set to 255. If I print the value of XMax in the constructor of the class "10" is the result. But when "using" the application 255 is the value of XMax.
How do I get the value of XMax that is set in the properties window? I want to store that value as a default value when my program is running.
Please, help.
/Anders
|
|
|
|
|
The properties and events changed in the properties window at design time are mapped to lines of code in FormName.Designer.cs
If you expand the + next to your form in solution explorer, you'll see it, then right click / view code and you can see the auto-generated code.
The flow of logic explains how they're implemented.
----
If you want to change the default value of a property, as it appears in the designer, then you need to apply attributes to your properties. In this case,
[DefaultValue(5)]
Look up System.ComponentModel namespace in MSDN in particular
|
|
|
|
|
In InitializeComponent() ;
|
|
|
|
|
Hi All,
My app seems to run ok on vista, apart from one thing-
it writes to the registry to set up file associations.
Whilst this works fine in XP, in vista i get security exceptions if i'm not an administrator.
Is there a non-administrator way to programmatically configure file associations in vista?
or, how can i invoke UAC in order to gain the correct permissions to access the registry?
Thanks
Jon
|
|
|
|
|
There is not a non-admin way to manipulate that part of the registry. Since you are configuring file associations, the proper way to do that would be as part of the application installer, which will already be running with the required elavated privileges.
-----------------------------
In just two days, tomorrow will be yesterday.
|
|
|
|
|
Write your associations to HKEY_CURRENT_USER\Software\Classes instead of HKEY_CLASSES_ROOT.
That way they will be set up only for the current user.
If you want to set up associations for all users on the machine, that requires administrative rights. The easiest way to get a UAC prompt is to create a separate .exe with a manifest (with requestedExecutionLevel). The other way would be COM elevation[^].
|
|
|
|
|
Hi,
I'm trying to copy a bitmap of a user control to the clipboard and then into OpenOffice Writer.
The problem I have is that nothing gets copied into OpenOffice Writer. I always have to first paste the bitmap to WordPad, then copy it again to the clipboard from there and only then can I paste the bitmap into OOWriter.
The issue seems to be the format of the bitmap I copy to the clipboard (BITMAP and DIB BITMAP - according to Clipboard Viewer). When I add the step using WordPad, it adds the formats ENHANCED METAFILE and PICTURE.
Here's the question: How can I also copy the bitmap as Enhanced Metafile and Picture, as that would probably solve my problem.
Here's the code I'm using:
<br />
Point topLeft = this.PointToScreen(this.Location);<br />
Size screenshotSize = this.Size;<br />
<br />
Bitmap bmpScreenshot = new Bitmap(screenshotSize.Width, screenshotSize.Height, PixelFormat.Format32bppArgb);<br />
<br />
Graphics gfxScreenshot = Graphics.FromImage(bmpScreenshot);<br />
gfxScreenshot.CopyFromScreen(topLeft, new Point(0, 0), screenshotSize, CopyPixelOperation.SourceCopy);<br />
<br />
Clipboard.SetImage(bmpScreenshot);<br />
<br />
Any help is appreciated. Thanks
|
|
|
|
|
On 2 dbservers we have tables that are equal to achother.
One production DB server and one TestDB Server (Different machines!)
They both have the same tables.
I want to check one table on btoh systems row by row.
I know that the first 10000 rows are equal.
But if I check DataRows with
if (test.Rows[i] != production.Rows[i]) {}
the statement always return true even if both rows have the same data!
How can I properly check the values in the DataRow if they really have differences?
I tried with ItemArray too, but no success.
|
|
|
|
General 
News 
Suggestion 
Question 
Bug 
Answer 
Joke 
Praise 
Rant 
Admin 
Submit an article or tip
