C# - 如何传递对需要 out 变量的函数的引用？

Question

public class Foo
{
    public void DoFoo()
    {
       int x;
       var coll = TheFunc("bar", out x);
    }

    public Func<string, int, ICollection<string>> TheFunc { get; set; }
}

错误：“参数 2 不应与 'out' 关键字一起传递。”

public class Foo
{
    public void DoFoo()
    {
       int x;
       var coll = TheFunc("bar", out x);
    }

    public Func<string, out int, ICollection<string>> TheFunc { get; set; }
}

错误：“变体修饰符无效。只能将接口和委托类型参数指定为变体。” >

如何在该函数中获取输出参数？

Answer 1

定义委托类型：

public delegate ICollection<string> FooDelegate(string a, out int b);

public class Foo
{
    public void DoFoo()
    {
       int x;
       var coll = TheFunc("bar", out x);
    }

    public FooDelegate TheFunc { get; set; }
}

Answer 2

您需要创建自己的代表：

delegate ICollection<string> MyFunc(string x, out int y);