C# try-catch-else

Question

One thing that has bugged me with exception handling coming from Python to C# is that in C# there doesn't appear to be any way of specifying an else clause. For example, in Python I could write something like this (Note, this is just an example. I'm not asking what is the best way to read a file):

try
{
    reader = new StreamReader(path);
}
catch (Exception)
{
    // Uh oh something went wrong with opening the file for reading
}
else
{
    string line = reader.ReadLine();
    char character = line[30];
}

From what I have seen in most C# code people would just write the following:

try
{
    reader = new StreamReader(path);
    string line = reader.ReadLine();
    char character = line[30];
}
catch (Exception)
{
    // Uh oh something went wrong, but where?
}

The trouble with this is that I don't want to catch out of range exception coming from the fact that the first line in the file may not contain more than 30 characters. I only want to catch exceptions relating to the reading of the file stream. Is there any similar construct I can use in C# to achieve the same thing?

Answer 1

Catch a specific class of exceptions

try
{
    reader = new StreamReader(path);
    string line = reader.ReadLine();
    char character = line[30];
}
catch (IOException ex)
{
    // Uh oh something went wrong with I/O
}
catch (Exception ex)
{
    // Uh oh something else went wrong
    throw; // unless you're very sure what you're doing here.
}

The second catch is optional, of course. And since you don't know what happened, swallowing this most general exception is very dangerous.

Answer 2

You could write it like:

bool success = false;
try {
    reader = new StreamReader(path);
    success = true;
}
catch(Exception) {
    // Uh oh something went wrong with opening the file for reading
}
finally {
    if(success) {
        string line = reader.ReadLine();    
        char character = line[30];
    }
}   

Answer 3

You can do this:

try
{
    reader = new StreamReader(path);
}
catch (Exception)
{
    // Uh oh something went wrong with opening the file for reading
}

string line = reader.ReadLine();
char character = line[30];

But of course, you will have to set reader into a correct state or return out of the method.