从另一个类访问公共 by​​te[] 数组

Question

在我正在编写的程序中，我有一个类，其中有一个我想要访问和使用的公共字节数组。

class HasByte
{
  public byte[] theByteArray = new byte[4];

  public HasByte(IPAddress someAddress)
  {
    theByteArray = someAddress.GetAddressBytes();
  }
}

class WantsByte
{ 
  IPAddress address = IPAddress.Parse("192.168.1.1");
  HasByte theInstance = new HasByte(address);
  //do something with theInstance.theByteArray[2] for example
}

目前，由于某种我想知道的原因，我通过 theInstance.theByteArray 访问的字节数组全为 0。

谢谢。

Answer 1

除了我在评论中所说的封装之外，这里的代码应该适合你，注意你不能在声明它的时候初始化实例，所以你把它移到构造函数：

    public class HasByte
    {
        public byte[] theByteArray = new byte[4];

        public HasByte(IPAddress someAddress)
        {
            theByteArray = someAddress.GetAddressBytes();
        }
    }

    public class WantsByte
    {
        IPAddress address = IPAddress.Parse("192.168.1.1");
        HasByte theInstance;
        public WantsByte()
        {
            theInstance = new HasByte(address);
        }

        //do something with theInstance.theByteArray[2] for example
    }

Answer 2

在您的类 WantsByte 中，您正试图通过另一个非静态成员 address 初始化成员 theInstance，编译器必须向 Error CS0236 抱怨。您可以将theInstance 初始化移动到构造函数：

class WantsByte
{ 
    IPAddress address = IPAddress.Parse("192.168.1.1");
    HasByte theInstance;

    public WantsByte()
    {
        theInstance = new HasByte(this.address);
    }
}

演示示例：

using System;
using System.Net;
using System.Linq;

public class Program
{
    public static void Main()
    {
        var wants = new WantsByte();    
    }
}

class HasByte
{
    public byte[] theByteArray = new byte[4];

    public HasByte(IPAddress someAddress)
    {
        theByteArray = someAddress.GetAddressBytes();
    }
}

class WantsByte
{ 
    IPAddress address = IPAddress.Parse("192.168.1.1");
    HasByte theInstance;

    public WantsByte()
    {
        theInstance = new HasByte(this.address);

        // do something with theInstance.theByteArray[2] for example
        // Let's print all elements of the array
        Console.WriteLine(String.Join(",", theInstance.theByteArray.Select(o => o.ToString()).ToArray()));
    }
}

给出输出：

192,168,1,1

或者，在WantsByte 类中，您可以将address 设为static 成员，这将保证在首次使用类之前对其进行初始化。然后你可以在theInstance初始化器中引用它：

using System;
using System.Net;
using System.Linq;

public class Program
{
    public static void Main()
    {
        var wants = new WantsByte();
        wants.DoSomethingWithHasByte();
    }
}

class HasByte
{
    public byte[] theByteArray = new byte[4];

    public HasByte(IPAddress someAddress)
    {
        theByteArray = someAddress.GetAddressBytes();
    }
}

class WantsByte
{ 
    static IPAddress address = IPAddress.Parse("192.168.1.1");

    HasByte theInstance = new HasByte(WantsByte.address);

    public void DoSomethingWithHasByte()
    {
        Console.WriteLine(String.Join(",", theInstance.theByteArray.Select(o => o.ToString()).ToArray()));
    }
}

也给出相同的输出：

192,168,1,1