Exception handling in Try-Catch block difference

There's no difference between the first and the second block, because all exceptions inherit from Exception. If you change Exception into another exception, OutOfMemoryException for example, then the code in the catch block will only be executed if the exception which is thrown a OutOfMemoryException is.

In the third block, the exception which is thrown is also stored in a variable, so you can get the error message for example:

try
{
    // some code
}
catch (Exception ex)
{
    Console.WriteLine(ex.Message); // writes the error message to the console
}

[EDIT]

Kaizen202 wrote:

In my program, I need to catch all exceptions and I don't want to log them. From the above mentioned Try-Catch blocks, which should be used?

If you don't need to specify a exception type, and if you don't want to log them, then use

try
{
    // some code
}
catch
{

}

And if you need to specify an exception type, but if you don't want to log them, then use

try
{
     // some code
}
catch (OutOfMemoryException) // change OutOfMemoryException into the type of the exception which you need to specify
{

}

But if you need to log them, then use

catch (Exception ex) // change Exception into the type of the exception which you want to log

Hope this helps.