Save file with appropriate extension in a Save File prompt

Question

In my application I use a SaveFileDialog to pop up a Save As window. I have restricted in the file type section the file to be saved as .dat with the following code.

sfdialog.Filter = "Data Files (*.dat*)|*.dat*";

What I want to know how to do is make it automatically save with the .dat extension. Currently it just saves with no extension unless I specifically save it as filename.dat.

Answer 1

SaveFileDialog dlg = new SaveFileDialog();
dlg.DefaultExt = "dat";
dlg.AddExtension = true;

Answer 2

The AddExtension and DefaultExt properties. For example:

sfdialog.DefaultExt = "dat";
sfdialog.AddExtension = True;