Question

下面的ArrayList可以直接初始化而不需要aFileExt字符串数组吗？

private static string[] aFileExt = 
     {"css", "gif", "htm", "html", "txt", "xml" };
private System.Collections.ArrayList alFileTypes =
     new System.Collections.ArrayList(aFileExt);

以下行是目标，但我的.Net编译器不喜欢它：

private static System.Collections.ArrayList alFileTypes = 
     new System.Collections.ArrayList({"css","gif","htm","html","txt","xml"});

我使用的是.net Micro Framework，因此无法访问泛型类型。

Answer 1

C＃1或2：

private static ArrayList alFileTypes = 
     new ArrayList(new string[] {"css","gif","htm","html","txt","xml"});

C＃3使用隐式类型数组：

private static ArrayList alFileTypes = 
    new ArrayList(new[] {"css","gif","htm","html","txt","xml"});

C＃3使用集合初始化程序：

private static ArrayList alFileTypes = 
    new ArrayList{"css","gif","htm","html","txt","xml"};

或者创建自己的帮助方法：

public static ArrayList CreateList(params object[] items)
{
    return new ArrayList(items);
}

然后：

static ArrayList alFileTypes = CreateList("css","gif","htm","html","txt","xml");

您没有使用通用集合的原因，顺便说一下？

Answer 2

如果您使用的是.NET 2.0或更高版本，则应使用通用的List<T>类型（即使它是List<object>，它将为您提供与ArrayList相同的功能）

如果您使用的是.NET 3.5或更高版本，则可以使用以下语法：

private static List<string> fileTypes = new List<string>()
{ 
    "css","gif","htm","html","txt","xml" 
};

但是，无论哪种方式，如果你想坚持ArrayList，你都可以这样做：

private static System.Collections.ArrayList alFileTypes = 
 new System.Collections.ArrayList(new object[] {"css","gif","htm","html","txt","xml"});

Answer 3

C＃3.0，使用通用List<T>，而不是ArrayList：

private static List<string> alFileTypes =
    new List<string> {"css","gif","htm","html","txt","xml"};

Answer 4

private static System.Collections.ArrayList alFileTypes = 
 new System.Collections.ArrayList(new string [] {"css","gif","htm","html","txt","xml"});

Answer 5

尝试

private static System.Collections.ArrayList alFileTypes =   new System.Collections.ArrayList(){"css","gif","htm","html","txt","xml"};

Answer 6

是的，只需更改

private static System.Collections.ArrayList alFileTypes = 
     new System.Collections.ArrayList({"css","gif","htm","html","txt","xml"});

到

private static System.Collections.ArrayList alFileTypes = 
     new System.Collections.ArrayList(new string[] {"css","gif","htm","html","txt","xml"});

使用常量文字初始化ArrayList

6 个答案: