[delphirocks]

OpenFileDialog openFileDialog1 = new OpenFileDialog();
			// save the last directorie the user has chosen
			openFileDialog1.InitialDirectory = "c:\\" ;
			openFileDialog1.Filter = "txt files (*.txt)|*.txt|htm files (*.htm)|*.htm|html files (*.html)|*.html" ;
			openFileDialog1.FilterIndex = 2 ;
			openFileDialog1.RestoreDirectory = true ;
			
			openFileDialog1.Multiselect = true;

			openFileDialog1.ShowDialog();
			int i=openFileDialog1.FileNames.Length;

Also in i steht die Anzahl der selektierten Files. Wo ist dein Showdialog Aufruf ?