Question

I’ve been confused by this problem for a very long time. I start the new thread by using System.Threading, just like this:

ParameterizedThreadStart threadFileExport = FileExport;
Thread threadExport = new Thread(threadFileExport)
{
    IsBackground = true,
    Name = "threadExport",
    Priority = ThreadPriority.AboveNormal
};
threadExport.Start(_dataTable);

and

public void FileExport(object objTable)
{

     SaveFileDialog saveFileDialog = new SaveFileDialog
     {
         DefaultExt = "xlsx",
         Filter = "Excel 2007-2010|*.xlsx|" +
                  "Excel95,97,2003|*.xls|",
         FileName = "table.xlsx",
         Title = "Save as. . ."
     };
saveFileDialog.ShowDialog();
}

But the dialog won’t show and it seems that the thread will abort immediately when executing “ShowDialog”. Is this a bug or I made a mistake? Can a background thread shows a savefile dialog?

Answer 1

No, a dialog must be shown on the UI thread, just as any other UI operation.