How can i say that the data have a .txt ending?

[robin voo]

If the program opens the saveFileDialog:
How can i say that the data have a .txt ending?

[GaryTexmo]

Have a look at the MSDN page for a SaveFileDialog. ..

http://msdn.microsoft.com/de-de/library/system.windows.forms.savefiledialog.aspx

(I even found you the German version :D)

Check out the Filter property. This takes a specific string format which will tell the dialog how it will find data. It basically works like this...

[quote]<description 1>|<pattern 1>|<descriptio n 2>|<pattern 2>|...|<descrip tion n>|<pattern n>"[/qouote]

So the code from the MSDN page reads as...

SaveFileDialog sfd = new SaveFileDialog();
sfd.Filter = "txt files (*.txt)|*.txt|All files (*.*)|*.*";

... and this means your save file dialog will have two options in the drop down, text files (which is first and thus default) and all files.