[Solved]-C# compare two Lists by one Property and change value of first List-LINQ,C#

If ID is unique within list_2 you can have a faster implementation (for large lists) by converting list to dictionary

  // A little bit of Linq: ToDictionary 
  var dict = list_2.ToDictionary(item => item.ID, item => item);
  ...
  foreach (item in list_1) {
    foo master;

    if (dict.TryGetValue(item.ID, out master)) {
      item.name = master.name; 
      item.color = master.color;
    }
  }