foreach, in (C# Reference)
The foreach statement repeats a group of embedded statements for each element in an array or an object collection that implements the System.Collections.IEnumerable or System.Collections.Generic.IEnumerable<T> interface. The foreach statement is used to iterate through the collection to get the information that you want, but can not be used to add or remove items from the source collection to avoid unpredictable side effects. If you need to add or remove items from the source collection, use a for loop.
The embedded statements continue to execute for each element in the array or collection. After the iteration has been completed for all the elements in the collection, control is transferred to the next statement following the foreach block.
For more information about the foreach keyword and code samples, see the following topics:
For more information, see the C# Language Specification. The language specification is the definitive source for C# syntax and usage.