Changing the text of label

[sujithkumarsl]

You can check you sample it will not work,i mean will not give the textchange i had tried this earlier... actually the thing is that my methods itself taking more time to execute. You know anyother methods

My small attempt...

[Sandeep Akhare]

Search for the Asynchronous processing that will help you

Thanks and Regards Sandeep If you want something you never had, do something you have never done!

[sujithkumarsl]

Can you just expalin, what you mean by that?

My small attempt...

[Rudolf Jan]

I think this cannot work. Setting the label text generates under water a message to the control. The label control then must update itself. If you change the label text three times inside the same method, you do not give control back to the message loop. So the message loop starts updating only after the third change and you will not notice the change. I'm not sure how to solve this. It may be a design error. Maybe you can solve this using an owner drawn label or by using timers.

[sujithkumarsl]

i got it......... we can use doevents for repainting the form....... thanks to all

My small attempt...

[Soundman32 2]

That won't work, it will just delay the code. You need to tell Windows to redraw the label with : label1.Text = " method1"; label1.Refresh(); method1(); label1.Text = "method2"; label1.Refresh(); method2(); label1.Text = "method3"; label1.Refresh(); method3() From the help for Control.Refresh: Forces the control to invalidate its client area and immediately redraw itself and any child controls.

[gumi_r msn com]

You can call Refresh() after each text change. It will force your control to repaint itself before executing the next method. If you're not concerned about an unresponsive UI and the slight performance loss when calling Refresh() then its the easiest solution.

[Dave Kreskowiak]

After you change the Text of the label, you're code doesn't go idle to allow the message pump to process the WM_PAINT message it receives because you changed the label. You need to call Application.DoEvents() to get your code to let the message pump do it's work. This is easily done if you move the code to change the label to a method:

UpdateStatusMessage("Calling method1...");
method1();
UpdateStatusMessage("Calling method2...");
method2();
UpdateStatusMessage("Calling method3...");
method3();

.
.
.
private void UpdateStatusMessage(string message)
{
label1.Text = message;
Application.DoEvents();
}

Dave Kreskowiak Microsoft MVP Visual Developer - Visual Basic
     2006, 2007

[Dave Kreskowiak]

This won't fix the problem. Sleeping the UI for 5 seconds, after each update of a label, will only hang his app unnecessarily. Application.DoEvents() is what is needed in his situation.

Dave Kreskowiak Microsoft MVP Visual Developer - Visual Basic
     2006, 2007

[Dave Kreskowiak]

Refresh won't work either because his code is not giving up control to allow the application's message pump to process the WM_PAINT messages and call the repaint code.

Dave Kreskowiak Microsoft MVP Visual Developer - Visual Basic
     2006, 2007

[gumi_r msn com]

Refresh() is equivalent to {Invalidate(true); Update();} and the Update() method forces the control to repaint itselft executing any pending WM_PAINT messages bypassing the application queue. Update() is equivalent to the UpdateWindow() function. More info in: http://msdn2.microsoft.com/en-us/library/ms534874.aspx[^]. I might be missing something, but try this code here. It works perfectly if you can bare an unresponsive UI. My label is refreshing perfectly. Its a simple form with a label and a button to start the test:

    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }


        private void button1_Click(object sender, EventArgs e)
        {
            doTest();
        }


        private void doTest()
        {
            label1.Text = "Starting Method 1...";
            label1.Refresh();
            anyMethodCall();
            label1.Text = "Starting Method 2...";
            label1.Refresh();
            anyMethodCall();
            label1.Text = "Starting Method 3...";
            label1.Refresh();
            anyMethodCall();
            label1.Text = "Starting Method 4...";
            label1.Refresh();
            anyMethodCall();
        }


        private void anyMethodCall()
        {
            System.Threading.Thread.Sleep(5000);
        }
    }

-- modified at 12:25 Thursday 3rd May, 2007

[gumi_r msn com]

Ok, I'm wrong, damn OS being smart and getting in the way :) My app fails to refresh if I try to move the window around. During the first 2 calls to anyMethodCall() my UI is unresponsive and my label is refreshing perfectly but then the window will start to move perfectly according to my mouse requests even if the app is still executing calls 3 and 4. And whats worse, my label stops refreshing. This is due (I guess) to Windows (Xp in this case, don't know if 2000 or previous work the same way) detecting my window as unresposive and taking action. DoEvents() will take care of this situation becuase it will inform the OS that my window is once again valid while Refresh() will not do that and the OS will keep on thinking its not responding. So yeah DoEvents() is the best solution because you can't rely on the user not trying to move the window around. My bad :) -- modified at 12:48 Thursday 3rd May, 2007

[sujithkumarsl]

this is what i done........ anyway thanks for all

My small attempt...

[Dave Kreskowiak]

gumi_r@msn.com wrote:

Ok, I'm wrong, damn OS being smart and getting in the way My app fails to refresh if I try to move the window around.

OK, but that wasn't the point behind using Application.DoEvents(). Try updating 6 or 7 controls during a blocking operation. Now you'e got to call Update on those controls, individually. Mking all the changes then calling Application.DoEvents() let's all those controls repaint themselves all at once, with a single call.

gumi_r@msn.com wrote:

So yeah DoEvents() is the best solution because you can't rely on the user not trying to move the window around. My bad

No big deal! :-D Everything has a purpose, even Refresh!

Dave Kreskowiak Microsoft MVP Visual Developer - Visual Basic
     2006, 2007