为什么构造函数不接受可访问性较低的类的参数？ [英] Why doesn't a constructor accept parameters of a class with lower accessibility?

问题描述

这里是：

我有两个窗体和一个类，我想通过参数将此类的实例从
Form1传递到Form2 （属于第二个窗体的构造函数。）

I have two Forms and one Class, I want to pass the instance of this Class from Form1 to Form2 through a parameter (which belongs to the second form's constructor).

public partial class Form1 : Form
{
    Class1 cl = new Class1();

    public Form1()
    {
        InitializeComponent();
    }

    private void button1_Click(object sender, EventArgs e)
    {
        Form2 frm_2 = new Form2(cl);
    }
}

因此，我收到以下错误：

Thus, I receive the folowing error:

可访问性不一致：参数类型'WindowsFormsApplication1.Class1'的可访问性比方法'WindowsFormsApplication1.Form2.Form2（WindowsFormsApplication1.Class1）'

public partial class Form2 : Form
{
    public Form2(Class1 c)
    {
        InitializeComponent();
        Class1 c_1 = new Class1();
        c_1 = c;
    }
}

谢谢。

推荐答案

您已将 Class1 定义为内部：

internal class Class1
{
}

或（相同）：

class Class1
{
}

但是您有公开方法（在本例中为构造函数），该方法接受类型为 Class1 的参数。 public 表示它在任何其他程序集中都是可见的，但是 internal 表示它仅在定义了该程序集的可见它（您的程序集）。因此，您有一个任何人都可以调用的方法，该方法接受只有您才能看到的类型的参数。那是行不通的。您在这里有两个选择：

But you have a public method (in this case a constructor) that accepts a parameter of type Class1. public means that it is visible from any other assembly, but internal means that it is only visible from the assembly that defines it (your assembly). So, you have a method that anyone can call, which accepts a parameter of a type that only you can see. That's not going to work. You have two options here:

public class Class1
{ }

如果您不介意可以从任何程序集访问该类。

If you don't mind the class being accessible from any assembly ever.

internal Form2(Class1 c)
{ }

如果您不介意除您之外的任何其他程序集都无法创建该表单。

If you don't mind that the form can never be created by any other assembly except yours.

这篇关于为什么构造函数不接受可访问性较低的类的参数？的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！