如何将 try-catch-finally 块转换为 C# 中的 using 语句？

Question

Say we create a IDisposable object, and we have a try-catch-finally block

var disposable= CreateIDisposable();
try{
  // do something with the disposable.
}catch(Exception e){
  // do something with the exception
}finally{
  disposable.Dispose();
}

How do I convert this to a using block?

If it were

var disposable= CreateIDisposable();
try{
  // do something with the disposable.
}finally{
  disposable.Dispose();
}

I would convert to

using(var disposable= CreateIDisposable()){
     // do something with the disposable.
}

How would I do this with the catch block?

try{
  using(var disposable= CreateIDisposable()){
     // do something with the disposable.
   }
}catch(Exception e){
  // do something with the exception
}

Answer 1

You're close. It's the other way around.

In reality, the CLR doesn't have try / catch / finally . It has try / catch , try / finally , and try / filter (that's what it does when the when clause is used on catch ). try / catch / finally in C# is just a try / catch within the try block of a try / finally .

So if you expand that and convert the try / finally to using , you get this:

using (var disposable = CreateIDisposable())
{
    try
    {
        // do something with the disposable.
    }
    catch (Exception e)
    {
        // do something with the exception
    }
}