C# 如何使用C获取与文件扩展名关联的程序名？

在不使用Microsoft.Win32.RegistryKey的情况下，如何使用C获取与文件扩展名关联的程序名？

使用WinApi函数

创建枚举和

创建一个助手方法

static string AssocQueryString(AssocStr association, string extension) {
     const int S_OK = 0;
     const int S_FALSE = 1;

     uint length = 0;
     uint ret = AssocQueryString(AssocF.ASSOCF_NONE, association, extension, null, null, ref length);
     if (ret != S_FALSE) {
         throw new InvalidOperationException("Could not determine associated string");
     }

     var sb = new StringBuilder((int)length);
     ret = AssocQueryString(AssocF.ASSOCF_NONE, association, extension, null, sb, ref length);
     if (ret != S_OK) {
        throw new InvalidOperationException("Could not determine associated string");
     }

     return sb.ToString();

}

你可以用这种方式

 static void Main(string[] args) {
           Console.WriteLine(AssocQueryString(AssocStr.ASSOCSTR_FRIENDLYAPPNAME, ".pdf"));
            Console.Read();
 }

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您建议的方法在内部查询注册表，因此这不是真正的答案。简单的回答是：它不会起作用。尽管我同意@HimBromBeere；我很喜欢这个选项。@Stefan好吧，毫无疑问，这是一个很好的方法。然而，它实际上并没有回答OP提供的问题。@HimBromBeere:奇怪的是，OP写下了这个答案。或许OP的意思只是不必直接摆弄Microsoft.Win32.RegistryKey？

static string AssocQueryString(AssocStr association, string extension) {
     const int S_OK = 0;
     const int S_FALSE = 1;

     uint length = 0;
     uint ret = AssocQueryString(AssocF.ASSOCF_NONE, association, extension, null, null, ref length);
     if (ret != S_FALSE) {
         throw new InvalidOperationException("Could not determine associated string");
     }

     var sb = new StringBuilder((int)length);
     ret = AssocQueryString(AssocF.ASSOCF_NONE, association, extension, null, sb, ref length);
     if (ret != S_OK) {
        throw new InvalidOperationException("Could not determine associated string");
     }

     return sb.ToString();

 static void Main(string[] args) {
           Console.WriteLine(AssocQueryString(AssocStr.ASSOCSTR_FRIENDLYAPPNAME, ".pdf"));
            Console.Read();
 }