"Pros Van Dessel" <Pros Van Des***@discussions.microsoft.com> wrote in
message news:F8932ACF-D6AB-460E-AC54-2FA5F27BA9BD@microsoft.com...
> I'm trying to build a windows forms application that monitors changes in
> the
> file system using a FileSystemWatcher
>
> object.  In the event handler of the watcher's 'Changed' event, i would
> like
> to display a message box.  If i do this,
>
> the messagebox is shown, but it is not displayed modal!
>
> If i replace the code 'MessageBox.Show( "Hi there!" );' with 'new
> Form().ShowDialog();', a modal form is shown, but
>
> this form does not behave 100% as a normal modal form (e.g. the title bar
> does not blink if i click the main form)
>
> I tried to set the SynchronizingObject property of the watcher (which
> makes
> the this.InvokeRequired test obsolete),
>
> but this did not change the behaviour.
>
> As a reference, i've also tried to launch modal forms from a
> System.Threading.Thread threadstart delegate and from a
>
> threadpool worker callback, but this all worked fine...
>
> What's so special about the FileSystemWatcher callback thread that it
> prevents forms from showing themselves as modal
>
> forms?
>
> Any ideas?
>
> Some code snippets can be found below:
>
> public class Form1 : System.Windows.Forms.Form
> {
>  private System.ComponentModel.Container components = null;
>  private FileSystemWatcher m_fileSystemWatcher;
>
>  public Form1()
>  {
>    InitializeComponent();
>    m_fileSystemWatcher = new FileSystemWatcher();
>    m_fileSystemWatcher.Filter = "*.txt";
>    m_fileSystemWatcher.Path = @"C:\";
>    m_fileSystemWatcher.NotifyFilter = NotifyFilters.LastWrite;
>    m_fileSystemWatcher.EnableRaisingEvents = true;
>    m_fileSystemWatcher.Changed += new
> FileSystemEventHandler(m_fileSystemWatcher_Changed);
>  }
>  ...
> }
>
> private void m_fileSystemWatcher_Changed(object sender,
> FileSystemEventArgs e)
> {
>  ShowMessageBox();
> }
>
>
> private void ShowMessageBox()
> {
>  if( this.InvokeRequired )
>  {
>    MethodInvoker invoker = new MethodInvoker( ShowMessageBox );
>    this.Invoke( invoker );
>    return;
>  }
>  MessageBox.Show( "Hi there!" );
> }

"CT" wrote:

> You're nearly there, just add the owner in teh call to MessageBox.Show, like
> this:
>
> MessageBox.Show(this, "Hi there!" );
>
>
> --
> Carsten Thomsen
> Communities - http://community.integratedsolutions.dk
>
> "Pros Van Dessel" <Pros Van Des***@discussions.microsoft.com> wrote in
> message news:F8932ACF-D6AB-460E-AC54-2FA5F27BA9BD@microsoft.com...
> > I'm trying to build a windows forms application that monitors changes in
> > the
> > file system using a FileSystemWatcher
> >
> > object.  In the event handler of the watcher's 'Changed' event, i would
> > like
> > to display a message box.  If i do this,
> >
> > the messagebox is shown, but it is not displayed modal!
> >
> > If i replace the code 'MessageBox.Show( "Hi there!" );' with 'new
> > Form().ShowDialog();', a modal form is shown, but
> >
> > this form does not behave 100% as a normal modal form (e.g. the title bar
> > does not blink if i click the main form)
> >
> > I tried to set the SynchronizingObject property of the watcher (which
> > makes
> > the this.InvokeRequired test obsolete),
> >
> > but this did not change the behaviour.
> >
> > As a reference, i've also tried to launch modal forms from a
> > System.Threading.Thread threadstart delegate and from a
> >
> > threadpool worker callback, but this all worked fine...
> >
> > What's so special about the FileSystemWatcher callback thread that it
> > prevents forms from showing themselves as modal
> >
> > forms?
> >
> > Any ideas?
> >
> > Some code snippets can be found below:
> >
> > public class Form1 : System.Windows.Forms.Form
> > {
> >  private System.ComponentModel.Container components = null;
> >  private FileSystemWatcher m_fileSystemWatcher;
> >
> >  public Form1()
> >  {
> >    InitializeComponent();
> >    m_fileSystemWatcher = new FileSystemWatcher();
> >    m_fileSystemWatcher.Filter = "*.txt";
> >    m_fileSystemWatcher.Path = @"C:\";
> >    m_fileSystemWatcher.NotifyFilter = NotifyFilters.LastWrite;
> >    m_fileSystemWatcher.EnableRaisingEvents = true;
> >    m_fileSystemWatcher.Changed += new
> > FileSystemEventHandler(m_fileSystemWatcher_Changed);
> >  }
> >  ...
> > }
> >
> > private void m_fileSystemWatcher_Changed(object sender,
> > FileSystemEventArgs e)
> > {
> >  ShowMessageBox();
> > }
> >
> >
> > private void ShowMessageBox()
> > {
> >  if( this.InvokeRequired )
> >  {
> >    MethodInvoker invoker = new MethodInvoker( ShowMessageBox );
> >    this.Invoke( invoker );
> >    return;
> >  }
> >  MessageBox.Show( "Hi there!" );
> > }
>
>
>