Member variables being re-initialised after MessageBox?

Question

I have a Form which has code similar to this:

public partial class Form1 : Form
{
    private int m_var1;
    private int m_var2;
    string sMsg;
    bool bReturn;

    private bool MyFunction()
    {
        // POINT A: at this point m_var1 and m_var2 are both 100            
        sMsg = "Test Message";
        bReturn = (DialogResult.Yes == MessageBox.Show(sMsg, "MyApp",MessageBoxButtons.YesNo, MessageBoxIcon.Question));
        // POINT B: at this point m_var1 and m_var2 are both 0
    }
}

Why at POINT B have m_var1 and m_var2 both changed to 0 as I am experiencing?

Please provide a small but complete sample project that reproduces this problem. This is no normal behavior and your question doesn't contain enough information to answer it. — Daniel Hilgarth, Oct 15 '12 at 10:47
Are the variables' values by any chance influenced by another thread? — waldrumpus, Oct 15 '12 at 10:47
Please give the code where your assigning the values to m_var1 and m_var2 or add full function code(MyFunction) — andy, Oct 15 '12 at 10:48
@DanielHilgarth: that is not feasible at the moment. Is there some way I can debug what is happening at the `MessageBox.Show` line? — CJ7, Oct 15 '12 at 11:23
@CJ7: `MessageBox.Show` surely has nothing to do with this phenomen. — Daniel Hilgarth, Oct 15 '12 at 11:25
@DanielHilgarth: well then what is it then? It happens only after that line. It cannot be anything other than something that happens between Point A and Point B. — CJ7, Oct 15 '12 at 11:28
@CJ7: `MessageBox.Show` doesn't change your variables. Period. That's why I was asking for more code. You might have a thread that manipulates some data, but it really is impossible to say. — Daniel Hilgarth, Oct 15 '12 at 11:30
@DanielHilgarth: can I have a debugger running in the background to see what is happening? — CJ7, Oct 15 '12 at 11:33
@DanielHilgarth: using Carra's answer below I was able to find out that the Form.Activated event was resetting the variables. The MessageBox was causing the form to activate again! — CJ7, Oct 15 '12 at 12:16

score 2 · Accepted Answer · answered Oct 15 '12 at 11:37

2

This sounds like a thread issue. I can explain how I would try to solve this problem:

Change m_var1 and m_var2 to Properties.
Set a breakpoint to their setters.

Check the stacktrace of the code that hit the setter.

answered Oct 15 '12 at 11:37

Carra

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in visual studio you can have the debugger stop when any symbol is assigned a value. Ie you can set a break point when m_var1 is assigned, so you don't technically need to change them to properties – Rune FS Oct 15 '12 at 11:43
@CJ7 sorry won't help you since it doesn't work for managed code at least not according to http://stackoverflow.com/questions/160045/visual-studio-debugger-break-when-a-value-changes – Rune FS Oct 15 '12 at 11:55

Member variables being re-initialised after MessageBox?

1 Answers1