Question

In the following code, are the using blocks redundant or are they necessay to fully release resources?

using (var dialog = new AboutBox())
    dialog.ShowDialog();

using (var form = new OptionForm())
    form.Show();

Answer 1

The first example is not redundant. You should always dispose of an IDisposable the moment you are done with it and in the case of a modal form this exactly accomplishes the goal.

The second example though will lead to errors. The Show method returns immediately and the form continues to be displayed. However the generated using code will immediately Dispose the form and cause it to go away. The form should only be disposed once it’s finished showing.