Should IDisposable.Dispose() be made safe to call multiple times?

Question

Should implementations of IDisposable make Dispose() safe to call multiple times? Or the opposite? What approach to most .NET Framework classes take?

Specifically, i

Answer 1

Yes, your implementations of IDisposable.Dispose() should tolerate being called multiple times. After the first call to Dispose(), all other calls can just return immediately.

I would prefer the first part of your code example, to dispose and null the local variables as you go.

Be aware that your .Dispose() may be called multiple times even if you implement Dispose and null patterns in your code. If multiple consumers hold a reference to the same disposable object, then that object's Dispose will probably be called multiple times as those consumers drop their references to it.