如何通过列表属性C＃将对象拆分为对象列表

Question

I have an object which contains a property of type of List of another objects:

public class MyObject {
    public List<AnotherObject> MyProperty { get; set; }
}

MyProperty has several items.

I want to split MyObject into List<MyObject> by MyProperty items so that each MyObject contains MyProperty with only one AnotherObject as List<AnotherObject> .

How to do it?

Answer 1

Use Enumerable.Select to get an IEnumerable<MyObject> :

var splits = existing.MyProperty.Select(ao => new MyObject {MyProperty = new List<AnotherObject> {ao}});

If you specifically need a List<MyObject> :

var asList = splits.ToList();

Answer 2

One way I can think of is to implement the IClonable interface into your MyObject class. This way you can make independent copies of the base object. All other properties in the class MyObject will keep their values!

public class MyObject :ICloneable
{
    public List<AnotherObject> MyProperty { get; set; }

    public object Clone()
    {
        return this.MemberwiseClone();
    }
}

Then iterate over the List<AnotherObject> MyProperty create a copy and overwrite the List object in the copy:

Here is a working example:

MyObject mobj = new MyObject();
mobj.MyProperty = new List<UserQuery.AnotherObject>();
mobj.MyProperty.Add(new AnotherObject());
mobj.MyProperty.Add(new AnotherObject());
mobj.MyProperty.Add(new AnotherObject());
mobj.MyProperty.Add(new AnotherObject());
mobj.MyProperty.Add(new AnotherObject());
mobj.MyProperty.Add(new AnotherObject());


List<MyObject> splitList = new List<MyObject>();

for (int i = 0; i < mobj.MyProperty.Count; i++) 
{   
    // get the reference to the object from the list
    AnotherObject temp = mobj.MyProperty[i];
    // make a deep copy of the base object
    MyObject clone = mobj.Clone() as MyObject;
    // overwrite the internal list and put the reference to the item into the list
    clone.MyProperty = new List<AnotherObject> {temp};
    // add the copied object to the split list
    splitList.Add(clone);
}

Note that the AnotherObject items are just references! so changing the values in the list of the base object will change the values in the single list items of the copies!

Answer 3

Using LINQ:

var query = from p in obj.MyProperty
            select new MyObject() { MyProperty = new List<AnotherObject>() { p } };