Concatenation Operator: Concat

The Concat() method appends two sequences of the same type and returns a new sequence (collection).

Example: Concat in C#

IList<string> collection1 = new List<string>() { "One", "Two", "Three" };
IList<string> collection2 = new List<string>() { "Five", "Six"};

var collection3 = collection1.Concat(collection2);

foreach (string str in collection3)
    Console.WriteLine(str);

Output:
One
Two
Three
Five
Six
Example: Concat in C#

IList<int> collection1 = new List<int>() { 1, 2, 3 };
IList<int> collection2 = new List<int>() { 4, 5, 6 };

var collection3 = collection1.Concat(collection2);

foreach (int i in collection3)
    Console.WriteLine(i);

Output:
1
2
3
4
5
6

Concat operator is not supported in query syntax in C# or VB.Net.