What is the purpose of “using” keyword in C#? with example

The using keyword in C# serves two main purposes:

Resource Management: The primary purpose of the using keyword is to ensure the proper management and disposal of resources. It provides a convenient syntax for working with objects that implement the IDisposable interface. The IDisposable interface is used to release unmanaged resources and perform cleanup operations.

By using the using statement, you guarantee that the resources will be properly disposed of, even in the presence of exceptions or errors. It automatically calls the Dispose() method on the object when the block is exited, ensuring the release of resources.

Scoping and Object Lifetime: The using keyword also defines a limited scope for the object within the block. Once the block is exited, the object is automatically disposed of, freeing up system resources. This helps to prevent resource leaks and ensures efficient memory management.

Here's an example to illustrate the use of the using keyword:

using (FileStream fileStream = new FileStream("filename.txt", FileMode.Open))
{
    // Code that uses the file stream
    // Read or write operations, etc.
}

In this example, a FileStream object is created and assigned to the fileStream variable. The FileStream class implements IDisposable, so it can be used within a using statement. Within the block, you can perform various read or write operations using the fileStream object.

When the execution flow reaches the end of the using block or encounters an exception, the Dispose() method of the FileStream object is automatically called. This ensures that any unmanaged resources held by the FileStream are properly released, such as file handles.

Using the using keyword helps promote cleaner and more concise code by taking care of resource management and scoping in a convenient manner.