提供一种用于释放非托管资源的机制。
地址：https://docs.microsoft.com/zh-cn/dotnet/api/system.idisposable?view=netframework-4.8
标题：IDisposable 接口
using System; using System.IO; using System.Text.RegularExpressions; public class WordCount { private String filename = String.Empty; private int nWords = 0; private String pattern = @"\b\w+\b"; public WordCount(string filename) { if (! File.Exists(filename)) throw new FileNotFoundException("The file does not exist."); this.filename = filename; string txt = String.Empty; using (StreamReader sr = new StreamReader(filename)) { txt = sr.ReadToEnd(); } nWords = Regex.Matches(txt, pattern).Count; } public string FullName { get { return filename; } } public string Name { get { return Path.GetFileName(filename); } } public int Count { get { return nWords; } } }
using语句实际上是语法上的便利。 在编译时, 语言编译器将为try / finally块实现中间语言 (IL)。
有关using语句的详细信息, 请参阅using 语句或using 语句主题。
如果编程语言不支持像或using Visual Basic 中C#的语句这样的构造, 或者不想使用它, IDisposable.Dispose则可以从finally try /语句。 finally 下面的示例将上using一示例try / finally中的块替换为块。
using System; using System.IO; using System.Text.RegularExpressions; public class WordCount { private String filename = String.Empty; private int nWords = 0; private String pattern = @"\b\w+\b"; public WordCount(string filename) { if (! File.Exists(filename)) throw new FileNotFoundException("The file does not exist."); this.filename = filename; string txt = String.Empty; StreamReader sr = null; try { sr = new StreamReader(filename); txt = sr.ReadToEnd(); } finally { if (sr != null) sr.Dispose(); } nWords = Regex.Matches(txt, pattern).Count; } public string FullName { get { return filename; } } public string Name { get { return Path.GetFileName(filename); } } public int Count { get { return nWords; } } }
原文：https://www.cnblogs.com/Tpf386/p/11996941.html