如何检查 catch 块中抛出的异常类型？

Question

I have something like this:

catch (Exception ex)
 {
      if (ex is "Exception Type")
      {

      }
      else if (ex is SqlException)
      {

      }
      else if 
      {
        ...
        ...
        ...
 }

Is this right in C# and what does the is mean anyway, which is its role or is there another way?

Answer 1

Yes, there is another way. By calling the specific exceptions that could possibly occur when running a block of code:

try {
   // Do something
}
catch(SqlException ex) {

}
catch(AnotherException ex) {

}

Then it is very important to start with the most specific exception and work your way towards a general exception.

Answer 2

Multiple catch blocks is an answer( docs ):

try
{
}
catch (SqlException ex)
{
    ...    
}
catch(AnotherExceptionType ex)
{
     ...
}

you can add as many as you like after your try block.

UPD As added in comments to this answer - order is important, so if you have exceptions hierarchy catch derived ones first.

Answer 3

Classic option:

try
{
    return DoStuff();    
}
catch (InvalidOperationException opEx)
{
    return HandleInvalidOp(opEx);
}
catch (DivideByZeroException divEx)
{
    return HandleDivException(divEx);
}
catch (Exception ex)  // final catch-all
{
    return HandleEx(ex);
}

Using pattern matching switch:

try
{
    return DoStuff();
}
catch (Exception ex)
{
    switch (ex)
    {
        case InvalidOperationException opEx:
            return HandleInvalidOp(opEx);
        case DivideByZeroException divEx:
            return HandleDivException(divEx);
        default:
            return HandleEx(ex);
    }
}