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c# custom messageBox show

I need to show up custom messageBox and close it when operation is done.
Problem is messageBox appear normal but without added label wich shows message , i can see only white space...After job is done , messageBox closing work normal.
here is code
public void resetirajSve() {
MyMessageBox poruka = new MyMessageBox();
poruka.Show();
analizaPodataka();
glProstor.Rows.Clear();
poruka.Close();
}
I tried using poruka.ShowDialog() but then code wont to continue executing.. with showDialog method label apper normal...
public partial class MyMessageBox : Form
{
public MyMessageBox()
{
InitializeComponent();
}
}

Some pointers:
1.It seems your custom MessageBox actually inherits a Form. The default MessageBox is rather versatile - see some examples, so there's no need to reinvent the wheel. Focus on more important things.
2.Using ShowDialog() will block all actions from executing on the Form until the newly opened form (you call it MyMessageBox, but it's actually a Form).
3.You could just add a ProgressBar control to display the task's progress and use the wait cursor until it is finished.
4.To avoid the program window becoming unresponsive until the method has finished executing (it can be an issue if it takes a long time), you might want to take a look at asynchronous programming. Here's an example.

How to correctly pause/delay Windows Forms application

I am a beginner to the OOP and the C#.
I am working on a quiz game using the Windows Forms.
My problem is related to two classes, the form and the game logic.
I have a basic UI with classic Froms controls. Take a look.
The thing I want to achieve is, when a player presses any answer button, it will higlight that pressed button by red or green color, depending on if it is right or wrong answer. After changing the color I want the program to wait for a while and then go to the next question.
Probelm is, that I don´t know how to achieve this correctly. I don´t know how to work with threads and how exactly the Form app works related to threads. Should I use a thread sleep or a timer or a async?
I will show you the method in game logic class which should handle this.
public static void Play(char answer) //Method gets a char representing a palyer answer
{
if (_rightAnswer == answer) //If the answer is true, the button should become green
{
Program.MainWindow.ChangeBtnColor(answer, System.Drawing.Color.LightGreen);
_score++;
}
else //Otherwise the button becomes Red
{
Program.MainWindow.ChangeBtnColor(answer, System.Drawing.Color.Red);
}
//SLEEP HERE
if (!(_currentIndex < _maxIndex)) //If it is the last question, show game over
{
Program.MainWindow.DisplayGameOver(_score);
}
else //If it is not the last question, load next question and dispaly it and finally change the button color to default
{
_currentIndex++;
_currentQuestion = Database.ListOfQuestions.ElementAt(_currentIndex);
_rightAnswer = _currentQuestion.RightAnswer;
Program.MainWindow.DisplayStats(_score, _currentIndex + 1, _maxIndex + 1);
Program.MainWindow.DisplayQuestion(_currentQuestion.Text);
Program.MainWindow.DisplayChoices(_currentQuestion.Choices);
}
Program.MainWindow.ChangeBtnColor(answer, System.Drawing.SystemColors.ControlLight);
}
I don´t want to completely block the UI but also I don´t want users to make other events by pressing other buttons during the pause. Because it will result in improper run of app.

If the program is really simple and you do not want to implement Threads I would suggest using Timer. Just start your Timer when clicking answer button. Your timer should contain function which would stop itself after some time and do other actions needed (e.g. pick another question).

Once the user has selected an answer you can disable all the buttons so they can't press anything else.
Then start a timer so you don't block the UI. The timer is basically a thread but handles all the threading for you so you don't have to worry about that aspect.
When the timer reaches the desired delay stop it and fire an event to select the next question.

At //SLEEP HERE add this line of code
Timer timer = new Timer(new TimerCallback(timerCb), null, 2000, 0);
The 2000 is milliseconds and is the wait time, timerCb is a call back method.
Also under that disable all your buttons so new events wont be generated.
private void timerCb(object state)
{
Dispatcher.Invoke(() =>
{
label1.Content = "Foo!";
});
}
You can do whatever you want in the callback, however if you do something that would change anything in the UI, you need to use the Dispatcher like I have changing the label content.

Suspending execution in a GUI scenario is very easy thanks to await:
await Task.Delay(2000);
This does not block the UI.
You should research what await does and how to use it. If you have never heard about it and are programming WinForms you are doing something wrong.
No timers or threads are needed. No callbacks, no Invoke.

How to clear the text inside a TextBox when it is being passed down in a function?

Here is what my code looks like:
private void exportToExcelButton_Click(object sender, EventArgs e)
{
txtBox.Clear();
txtBox.AppendText("Beginning Export...");
ExportExcel(txtBox);
txtBox.AppendText("Export complete...");
}
The problem I am having is that whenever the button is clicked (to execute the function above), only part of the current text in the TextBox (System.Windows.Forms.TextBox) is cleared, and replaced with the first line: "Beginning Export ...".
However once the function ExportExcel(txtBox) is done executing, then the entire text is replaced by the new one generated in ExportExcel(txtBox).
Inside ExportExcel(txtBox); I have several txtBox.AppendText() statements explaining to the user the actions being made.
I have tried clearing the text with txtBox.Text = String.Empty; and txtBox.Text = "";and neither have worked.
Let me know if anything needs to be clarified, thanks.

Looks like you're blocking the GUI thread, preventing the text box from redrawing itself. This is one reason why you shouldn't perform long-running tasks on the GUI thread. Use a background thread instead. That way you leave the GUI thread free to perform important operations like drawing, responding to mouse clicks, etc.

Have you tried the textBox.Refresh , before calling txtBox.AppendText("Beginning Export...").
The method invalidates the control.
On the other hand, if you use a background thread, then you should update the UI only by overriding the Progress Changed event. Background threads are not meant for updating user interfaces. Try searching for Worker threads and UI threads. They correlate to MFC, but the concept is the same.
Also keep in mind the cross thread calls.

I agree with dvnrrs. However if you are unable to do this, try calling txtBox.Refresh();after adding each line of text.
There is another method called Application.DoEvents(); that has a similar behavior, but its use is not recommended since it sort of short-circuits the normal application flow and can cause your application to fail unexpectedly or do strange things.

C# - Cross-thread operation - Create Control in thread, add to main form

I have an older form that I really don't want to rewrite at this point, so what I'm doing is loading the form and then adding it to a panel in the new UI form. This is working fine, but it's slow. The old form does a lot of loading and gathering of data and it's not very efficient. So as a result larger records take up to 30 seconds to load. As you know, creating the form then "locks up" the main UI for about 30 seconds while it loads the old form. This is the action I'm trying to prevent. I want to load the new form, display a "Loading" gif in the blank panel, and then once the old form is loaded remove the "Loading" image and add the form as a control.
And here starts the problem.
I've tried creating a Background Worker but this causes a STA error (old form has a few threaded data loadings of it's own), and since I can't change the worker to STA I stopped trying.
I've tried to create an Invoke (and BeginInvoke) and while this works, it doesn't really load the old form in the thread. It simply sends it back to the UI thread and does the work there. Again this hangs the UI. I.E.: Not what I want.
I've tried to create a delegate and trigger it as an event in the thread, but I get the same results as below...
I've created a thread, set STA on it, started it and then did a while loop with a DoEvents waiting on it to finish. Of course this all seems to work up to the point of accually adding the form to the panel, and then I get the "Control 'ChartForm' accesses from a thread other than the thread it was created on". In this error 'ChartForm' is the old chart that was loaded in the thread.
I've tried the above method, but I instead used a private static field to hold the creating of the old form, and then adding it to the panel once the thread is completed. This is in the method that created the thread, just after the while loop. Same error.
So, I've used the above method in other places with DataTables and didn't have any issue getting the data back to the main thread for use with DataBinding. I know that this is a little different but I didn't think that it would be this hard to do.
Below is the code that I have tried to use that seems to be the closest to what I want.
private static _ChartForm;
private void LoadPatientChart()
{
ClearMainPanel(); // Removes any loaded ChartForms from Panel
if (_Patient == null) // Test to make sure a patient is loaded
return;
loadingPanel.Visible = true; // Displays the "Loading" gif
Thread thread = new Thread(new ThreadStart(this.GetChartForm));
thread.SetApartmentState(ApartmentState.STA);
thread.Start();
while (thread.ThreadState != ThreadState.Stopped)
Application.DoEvents(); // Keeps the UI active and waits for the form to load
this.ChartPanel.Controls.Add(_ChartForm); // This is where the error is
loadingPanel.Visible = false; // Hide the "Loading" gif
}
private void GetChartForm()
{
ChartForm chartForm = new ChartForm(_Patient.AcctNum.ToString(), false);
chartForm.TopLevel = false;
chartForm.FormBorderStyle = FormBorderStyle.None;
chartForm.Dock = DockStyle.Fill;
chartForm.Visible = true;
_ChartForm = chartForm;
}

It's really not a good idea to create UI controls on any other thread than the UI thread. It is technically possible, but it's difficult to manage, especially if the new thread is a "temporary" one.
What you really need to do is refactor out the work that the ChartForm is doing (on construction it appears?) and do that work on a background thread, and then return it to your UI thread and then create your ChartForm passing in the results of that work. IMHO this is a better design anyways; although it may be a lot of work for you.

I don't think what you want is possible without refactoring this "old form". There is only one UI thread, and all UI elements must be created on that thread to be displayed to the user.
I would suggest refactoring the form to display initially without any data (or maybe with a loading image), and then have the form start a background task using BackgroundWorker to perform the long running tasks that are not UI related (going to a database, etc.) Once the worker is complete, then you can run the code that initializes the Form's data elements. This will keep the UI responsive for as long as possible while the blocking tasks are performed.

I've tried to create an Invoke (and BeginInvoke) and while this works,
it doesn't really load the old form in the thread. It simply sends it
back to the UI thread and does the work there. Again this hangs the
UI. I.E.: Not what I want.
You must update the user interface on the main thread, you do not have any choice, if its still hanging then your doing the calculations in the wrong thread.

Showing Multiple Instances Of Same Form?

I'm having some serious issues with a WinForm application that I'm working on.
Currently, I'm using Form1.ShowDialog(); to display a form. This code is contained in a background worker that looks for changes in a database. Using Form1.ShowDialog(); only allows 1 form to open at a time, even if there are multiple changes to the database. What I want to have happen is for multiple forms to open at once if there is more than one change in my database.
When I use Form1.Show();, the application blows up. For some reason, the Show() method makes the forms not display properly (all the elements in the form are missing).
Is there anything I can do to make my code work the way I want it to?
Edit: here's a code snippet
//result is a linq result
foreach (var row in result)
{
Form1 Form = new Form1();
Form.ShowDialog();
}

After a first look, I can tell you this:
Showdialog can't work the way you intend: this very method makes the owner inactive until the dialog is closed. In your case, the loop will pause at the first showdialog, then resume when you close the form, opening a new one and so on until the loop is finished.
As for the "show" problem, creating empty forms, I need more information. The rest of the code and the exception(s) you're getting.

Two points from the top of my head:
1) To open more then one form , use non modal (modeless) method (i think
the show() method). see for example http://msdn.microsoft.com/en-us/library/39wcs2dh.aspx
2) I am not sure you can call UI related method from a non UI thread. You might want to send an event to your UI thread from the worker thread and the UI thread will call the show method