Question

objA = new obj()
{
    ID = 123,
    attriA = "",
    attriB = "someValueB"
}

objB = new obj()
{
    ID = 123,
    attriA = "someValueA",
    attriB = ""
}

List<obj> ListA = new List<obj>();
ListA.add(objA);

List<obj> ListB = new List<obj>();
ListB.add(objB);

鉴于上述情况，我需要listC以下对象：

objC = new obj()
{
    ID = 123,
    attriA = "someValueA",
    attriB = "someBalueB"
}

这是我尝试过的。它有效，但我认为必须有办法缩短代码，使用linQ我不知道：

foreach(obj item in ListA)
{
    obj objB = ListB.Where(x=> x.ID == item.ID).FirstOrDefault();

    obj objC = new obj(){
        ID = objB.ID;
        attriA = item.attriA;
        attriB = objB.attriB;
    };
    ListC.add(objC);
}

Answer 1

您可以使用linq join，如下所示

 var query = from a in ListA
                join b in ListB
                     on a.ID equals b.ID
                select new Obj()
                {
                     ID = b.ID;
                attriA = a.attriA;
             attriB = b.attriB;
                };

以上代码未经过测试

Answer 2

如果总有字符串，你可以用这样的东西：

var listC = ListA.Join(ListB, 
            A => A.ID, B => B.ID, 
            (A, B) => new {
                ID = A.ID,
                attriA = !string.IsNullOrEmpty(A.attriA) ? A.attriA : B.attriA,
                attriB = !string.IsNullOrEmpty(B.attriB) ? B.attriB : A.attriB
            });

Linq加入两个类似的对象列表？

2 个答案: