c# - Deep copy of List<T>

Question

I'm trying to make a deep copy of a generic list, and am wondering if there is any other way then creating the copying method and actually copying over each member one at a time. I have a class that looks somewhat like this:

public class Data
{            
    private string comment;
    public string Comment
    {
        get { return comment; }
        set { comment = value; }
    }

    private List<double> traceData;
    public List<double> TraceData
    {
        get { return traceData; }
        set { traceData = value; }
    }
}

And I have a list of the above data, i.e List<Data>. What I'm trying to do is plot a trace data of the subset of List onto a graph, possibly with some scaling or sweeping on the data. I obviously don't need to plot everything in the list because they don't fit into the screen.

I initially tried getting the subset of the list using the List.GetRange() method, but it seems that the underneath List<double> is being shallow copied instead of deep copied. When I get the subset again using List.GetRange(), I get previously modified data, not the raw data retrieved elsewhere.

Can anyone give me a direction on how to approach this? Thanks a lot.

Answer 1

The idiomatic way to approach this in C# is to implement ICloneable on your Data, and write a Clone method that does the deep copy (and then presumably a Enumerable.CloneRange method that can clone part of your list at once.) There isn't any built-in trick or framework method to make it easier than that.

Unless memory and performance are a real concern, I suggest that you try hard to redesign it to operate on immutable Data objects, though, instead. It'll wind up much simpler.