更新：2007 年 11 月

本示例演示在向方法传递结构时，传递的是该结构的副本，而在传递类实例时，传递的是一个引用。

本示例的输出表明：当向 ClassTaker 方法传递类实例时，只更改类字段的值。但是向 StructTaker 方法传递结构实例并不更改结构字段。这是因为向 StructTaker 方法传递的是结构的副本，而向 ClassTaker 方法传递的是对类的引用。

示例

C# 复制代码
class TheClass
{
    public string willIChange;
}

struct TheStruct
{
    public string willIChange;
}

class TestClassAndStruct
{
    static void ClassTaker(TheClass c)
    {
        c.willIChange = "Changed";
    }

    static void StructTaker(TheStruct s)
    {
        s.willIChange = "Changed";
    }

    static void Main()
    {
        TheClass testClass = new TheClass();
        TheStruct testStruct = new TheStruct();

        testClass.willIChange = "Not Changed";
        testStruct.willIChange = "Not Changed";

        ClassTaker(testClass);
        StructTaker(testStruct);

        Console.WriteLine("Class field = {0}", testClass.willIChange);
        Console.WriteLine("Struct field = {0}", testStruct.willIChange);

        // Keep the console window open in debug mode.
        Console.WriteLine("Press any key to exit.");
        Console.ReadKey();
    }
}
/* Output:
    Class field = Changed
    Struct field = Not Changed
*/

请参见