Timer starts only after the Form is closed

Question

I am currently working on a C# application that runs on a Windows CE 5 device with MS Compact Framework 2.0. In this application I call a singleton dialog from a keyboard-hook asynchronously via BeginInvoke:

this.BeginInvoke((ThreadStart)delegate()
{
    DlgX.getInstance().display(TaskController.getInstance().getActiveTask().getValues(), true);
});

In the display method of the dialog I want to set the focus to a certain control. As the Win CE device is very slow, I have to use a timer to delay the Focus() execution:

System.Windows.Forms.Timer timer = new System.Windows.Forms.Timer();
timer.Interval = 600;
timer.Enabled = true;
timer.Tick += (EventHandler)delegate(object obj, EventArgs args)
{
    button1.Focus();
    timer.Dispose();
};

Unfortunately this does not work. The timer gets executed as soon as I close the dialog. What am I doing wrong?

Thank you in advance for any help!

edit: This is the whole display() method of the dialog:

public void display(List<InputRow> fvList, bool validate)
{
    this.fvList = fvList;
    ctlCount = (fvList.Count > 5 ? 5 : fvList.Count);
    for (int i = 0; i < ctlCount; i++)
    {
         //some 100% irrelevant stuff
    }
    button1.KeyDown += new KeyEventHandler(btnOK_KeyDown);
    button1.Click += new EventHandler(btnOK_Click);
    if (!this.Visible)
    {
        ShowDialog();
    }
    if (validate)
    {
        System.Windows.Forms.Timer timer = new System.Windows.Forms.Timer();
        timer.Interval = 600;
        timer.Enabled = true;
        timer.Tick += (EventHandler)delegate(object obj, EventArgs args)
        {
            button1.Focus();
            timer.Dispose();
        };
    }
}

Answer 1

The timer instantiation and enabling is evaluated when you close your form, because ShowDialog is synchronous. You should put your timer before your ShowDialog