Скачать или смотреть The MessageBox

There are four parameters available in the MessageBox.Show method. They are: 1) the message itself; 2) a MessageBox title; 3) a set of buttons other than just the familiar “OK”; and 4) an icon that can express the type of message being displayed (informational, question, error and so on).

When you see the possible button configurations available with the MessageBox you will quickly see that the MessageBox can be an excellent way to let the user make a decision. And, based on that user decision, the application can proceed down several different tracks. Basically, the MessageBox is a visual "IF" statement.