Is there a difference in the order of catch blocks in a try-catch construct?

Yes, there is a difference. catch blocks are checked sequentially from top to bottom.

More specific exceptions should come first, and more general ones last. If a catch block for a more general exception is placed above a block for a more specific one, the code for handling the specific exception will never be executed because the exception will be caught by the more general block.

For example:

try
{
    // Some code that may throw exceptions
}
catch (DivideByZeroException ex) // More specific exception
{
    // Handling division by zero
    Console.WriteLine($"Error: division by zero. {ex.Message}");
}
catch (Exception ex) // More general exception
{
    // Handling any other exception
    Console.WriteLine($"An error occurred: {ex.Message}");
}

If you swap the places of catch (Exception ex) and catch (DivideByZeroException ex), then when a DivideByZeroException occurs, it will be caught by the first catch (Exception ex) block, and the code for handling division by zero will never be executed.