Merge two object lists in C# with LINQ

Question

I have two List<T>s which are both the same type. Is there an easy way to merge to the two sets without looping though both sets and merging them into a third?

Code

var myObject= new List<Core.MyObject>();
var myObject2= new List<Core.MyObject>();

if(!string.IsNullOrEmpty(txb.Text))
{
    var repository = ServiceLocator.Current.GetInstance<Core.RepositoryInterfaces.IRepository>();
    myObject= repository.GetWherePostCodeLike(txb.Text).ToList();
}

if(!string.IsNullOrWhiteSpace(ddl.SelectedValue))
{
    var repository = ServiceLocator.Current.GetInstance<Core.RepositoryInterfaces.IRepository>();
    myObject2= repository.GetNearTownX(ddlLocations.SelectedValue).ToList();
}

It would have been nice to able able to just use the += on the second, but this is not allowed... Any ideas?

it is possible thorugh linq if im not mistaken. stackoverflow.com/questions/2298207/… — Patrick
– Patrick, Commented May 11, 2011 at 16:19
Yea I know there not data sets I have made an edit to show this. — TheAlbear
– TheAlbear, Commented May 13, 2011 at 10:41

SLaks · Accepted Answer · 2011-05-11 16:17:20Z

8

Call the Concat (keeps duplicates) or Union (skips duplicates) LINQ methods

IEnumerable<MyObject> third = list.Concat(otherList);

To use Union, you'll need to override Equals and GetHashCode to compare objects by value. (or pass an IEqualityComparer<MyObject>)

answered May 11, 2011 at 16:17

SLaks

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1 Comment

TheAlbear Over a year ago

Thanks the Union in linq was just what I was looking for.

Lasse V. Karlsen · Accepted Answer · 2011-05-11 16:17:42Z

3

You got several alternatives.

You can concatenate them:

var combined = dataSet.Concat(dataSet2).ToList();

You can add one to the other:

dataSet.AddRange(dataSet2);

answered May 11, 2011 at 16:17

Lasse V. Karlsen

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Comments

Please treat your mods well. · Accepted Answer · 2011-05-11 16:19:03Z

1

You can do something like:

var merged = dataSet.Concat(dataSet2).ToList();

answered May 11, 2011 at 16:19

Please treat your mods well.

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