Using Clone() to duplicate an ASP.NET MVC / EntityFramework model object

Question

I've read this question about using Clone() and want to know if what I'm after will be achieved. My understanding from reading that question is that Clone() does a shallow copy, however reading elsewhere led me to believe differently, and now I'm confused.

Our project has a class Rule that has an ICollection<ICondition> Conditions. We'd like to provide users with a shortcut method to duplicate an existing Condition and modify it rather than start from scratch. To that end, we're providing a Copy To New button.

ICondition looks like this:

interface ICondition
{
    long ID { get; set; }
    string Description { get; set; }
    DateTime EffectiveDate { get; set; }
    string IfStatement { get; set; }
    string PriceVersion { get; set; }
    PriceDetail Pricing { get; set; }
    bool StandardOption { get; set; }
}

Given what I've read about Clone(), I'm fairly confident it would work the way I expect by using ICondition newCondition = conditionToCopy.Clone(), though I'm unsure if Pricing would be duplicated correctly, since it's a complex data type.

So, the first part of my question is, "will this work?" I would just try it and see, however ICondition (or really its underlying Condition) doesn't seem to provide a method for Clone(), which leads me to the second part of my question: can I leverage IClonable to enable this functionality? If so, where?

Is this the way?

public static class Condition : IClonable
{
    ...
    public Condition Clone(Condition conditionToClone)
    {
        return new Condition 
        { 
            Description = this.Description,
            EffectiveDate = this.EffectiveDate,
            IfStatement = this.IfStatement,
            PriceVersion = this.PriceVersion,
            Pricing = this.Pricing,
            StandardOption = this.StandardOption
        }
    }
}

And, given that as the answer, is there any utility to declaring IClonable as the interface? Does it add any value?

Update:

Based on the below answer, I decided to do this, which at least builds (and hopefully runs; haven't tried it yet):

public class Condition
{
    ...
    public Condition Clone()
    {
        return (Condition)base.MemberwiseClone();
    }
}

I still don't see the need for ICloneable, so have left it out. The compiler was complaining about it anyway, something about the base class not being object.

More reading, and I think what I was hoping for was something like `System.Object.MemberwiseClone` (https://msdn.microsoft.com/en-us/library/system.object.memberwiseclone%28v=vs.110%29.aspx), though try as I might, I can't seem to get IntelliSense to offer that as an option. :\ — J.D. Ray, Mar 06 '15 at 18:41
I too had in the past been confused on deep clones, clones etc. I almost never do it; rather, I use the pattern you show above almost all the time. — JWP, Mar 06 '15 at 18:46

score 2 · Accepted Answer · answered Mar 06 '15 at 18:47

2

There are couple of things. First Condition class should not be static. Second, PriceDetail class [Property pricing], Also need to impleemnt ICloneable. Instance class will allow base.MemberWiseClone() method.

public class Condition : ICloneable
{

    public object Clone()
    {
        base.MemberwiseClone();
    }
}

answered Mar 06 '15 at 18:47

Gaurav Sharma

586
3
10

But what's the usefulness of `ICloneable`? – J.D. Ray Mar 06 '15 at 19:19
It is basically for instructing compiler to copy "value" of properties than "reference" as it happens while copying Reference type variable. Creating new instance of a same class and passing same values will do the same thing, but this is more clean. – Gaurav Sharma Mar 06 '15 at 19:22
From reading MSDN (https://msdn.microsoft.com/query/dev11.query?appId=Dev11IDEF1&l=EN-US&k=k(System.ICloneable);k(TargetFrameworkMoniker-.NETFramework,Version%3Dv4.5.2);k(DevLang-csharp)&rd=true), as far as I can tell, `ICloneable` simply requires that you implement a method `Clone()` and does nothing else. – J.D. Ray Mar 06 '15 at 19:26
Also, should that be `{ return base.MemberwiseClone(); }` ?? – J.D. Ray Mar 06 '15 at 19:29
Yes we should return. – Gaurav Sharma Mar 06 '15 at 19:34

Using Clone() to duplicate an ASP.NET MVC / EntityFramework model object

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