using (C# reference)

The using keyword has two major uses:

• The using statement defines a scope at the end of which an object is disposed:

  sample · csharpdocs/csharp/language-reference/keywords/snippets/UsingKeywordExample.csUsingStatement

  csharpCopy

  // <UsingDirective>
  using System;
  using System.IO;
  // </UsingDirective>
  
  public class UsingStatementSample
  {
      public static void Main()
      {
          // <UsingStatement>
          string filePath = "example.txt";
          string textToWrite = "Hello, this is a test message!";
  
          // Use the using statement to ensure the StreamWriter is properly disposed of
          using (StreamWriter writer = new StreamWriter(filePath))
          {
              writer.WriteLine(textToWrite);
          }
          // </UsingStatement>
      }
  }

• The using directive creates an alias for a namespace or imports types defined in other namespaces:

  sample · csharpdocs/csharp/language-reference/keywords/snippets/UsingKeywordExample.csUsingDirective

  csharpCopy

  // <UsingDirective>
  using System;
  using System.IO;
  // </UsingDirective>
  
  public class UsingStatementSample
  {
      public static void Main()
      {
          // <UsingStatement>
          string filePath = "example.txt";
          string textToWrite = "Hello, this is a test message!";
  
          // Use the using statement to ensure the StreamWriter is properly disposed of
          using (StreamWriter writer = new StreamWriter(filePath))
          {
              writer.WriteLine(textToWrite);
          }
          // </UsingStatement>
      }
  }

#See also

• C# keywords