How to show compulsory fields on a windows form

Question

How should I show users which fields are compulsory in a windows forms application.

I have considered changing the label color or maybe the background color of the text box.

I use an error provider to show a red exclamation mark next to the field, however this is only visible after they have clicked the save button.

Answer 1

• Asterisk or icon to the side of control
• Red border when required validation fails (when user tries to save)
• Bold Labels
• Different background color for required controls (perhaps only when user tries to save)

Answer 2

Use the errorprovider extension control.

This places a red cross next to the control with a tooltip message.

Answer 3

Yellow background would make it similar to many web forms. No idea whether there are any standards for Windows per se, though if there are I doubt they are widely used.