Exception handling is a mechanism in C# that allows you to handle and manage runtime errors or exceptions that occur during the execution of a program.
In C#, exceptions are objects that are instances of classes derived from the built-in Exception class. When an exception occurs, an object of the appropriate exception class is thrown and the program flow is transferred to a catch block.
The basic syntax for exception handling in C# is as follows:
try
{
// code that may raise an exception
}
catch(ExceptionType1 ex)
{
// code to handle the exception of type ExceptionType1
}
catch(ExceptionType2 ex)
{
// code to handle the exception of type ExceptionType2
}
finally
{
// optional code that always executes, regardless of whether an exception occurred or not
}
In this syntax, the code that may raise an exception is enclosed in a try block. If an exception occurs within the try block, it is caught by the appropriate catch block based on the type of the exception. The catch blocks contain code to handle the exception, which can include logging the error, displaying a user-friendly message, or rethrowing the exception.
The finally block is optional and is used to specify code that always executes, regardless of whether an exception occurred or not. This block is typically used to release any resources that were acquired in the try block, such as closing a file or database connection.
You can also use multiple catch blocks to handle different types of exceptions. The catch blocks are evaluated in the order in which they are written, and the first catch block that matches the type of the thrown exception is executed.
In addition to the try…catch…finally syntax, C# also provides a using statement that can be used to automatically handle resource disposal and exception handling. The using statement ensures that the resources are properly disposed of, even if an exception occurs. Here’s an example:
try
{
using (var streamReader = new StreamReader(“file.txt”))
{
// code to read from the file
}
}
catch(IOException ex)
{
// code to handle exception
}
In this example, the StreamReader class is used to read from a file. The using statement ensures that the StreamReader object is properly disposed of, even if an exception occurs. If an IOException occurs, it is caught by the catch block and the code to handle the exception is executed.
Overall, exception handling in C# is an important aspect of writing robust and reliable code. It allows you to gracefully handle runtime errors and take appropriate actions to handle them.