在List <object>中合并两个属性上的对象

Question

public class Note
{
    public string account;
    public DateTime noteDate;
    public string noteText;
}

List<Note> List1;

使用LINQ我正在寻找一种方法来合并noteText account和noteDate相同的方式。例如，如果传入列表有三个对象：

List1[0] = "1234", 2017-10-03, "This is a"
List1[1] = "1234", 2017-10-03, " sample note."
List1[2] = "4321", 2017-10-03, "This is another note."

我希望新列表有两个对象：

List2[0] = "1234", 2017-10-03, "This is a sample note."
List2[1] = "4321", 2017-10-03, "This is another note."

Answer 1

最简单的方法是按日期和帐户分组，然后Join字符串字段：

List2 = List1.GroupBy(n => new {n.noteDate, n.account})
             .Select(g => new Note {
                 noteDate = g.Key.noteDate,
                 account  = g.Key.account,
                 noteText = string.Join("", g.Select(n => n.noteText))
                 });