How are arrays of structures allocated in C#-CodePudding

I am trying to allocate an array of structures in C#. For example,

public struct Channel {
    int ChannelId;
    // other stuff goes here... 
}

public  struct FrameTraffic {
    public int FrameId;
    public int MaxChannels;
    public Channel[] Channels;

    public FrameTraffic(int dummyCS0568 = 0)
    {
        this.FrameId = 0;
        MaxChannels = TableMgr.MaxChannels;
        Channels = new Channel[TableMgr.MaxChannels];
    }
}

But when I go to allocate an array of FrameTraffic structures, I see that Channels is null. This tells me that Channels is a reference rather than an array of structures. Am I correct? If so, then allocating the Channels array shouldn't embed the array into the structure, but simply satisfy the reference in the structure. I want the structures embedded. Is there a way to do this? Or am I incorrect in my assumptions?

CodePudding user response：

Answering the later part of your question and disregarding any other problem. Yes you are correct, this will be a reference to an array. However, if you wanted to embed the array in the struct you can use a

There are two things that i think is possibly causing this :

You are just initializing the array with size but not assigning any values
You might be initializing FrameTraffic with default construct instead of what you have defined (this caused the actual NPE for me)

Below is how you can adjust your code: (I have hardcoded values which is brought by TableMgr.MaxChannels since i dont have that)

class Program
{
    static void Main() 
    {
        FrameTraffic fT = new FrameTraffic(0);
        foreach (var item in fT.Channels)
        {
            Console.WriteLine(item.ChannelId);
        }
        Console.Read();
    }
}

public struct Channel
{
    public int ChannelId; //missing public exposer if you really want to reassign
    // other stuff goes here... 
}

public struct FrameTraffic
{
    public int FrameId;
    
    public Channel[] Channels;

    public FrameTraffic(int dummyCS0568 = 0)
    {
        this.FrameId = 0;
        const int MaxChannels = 1;
        //array requires size and its values assigned here 
        Channels = new Channel[MaxChannels]{ new Channel { ChannelId = 1 } };
    }
}