首先这是错误的:
public bool Equals(MyClass item1, MyClass item2)
{
return GetHashCode(item1) == GetHashCode(item2);
}
如果哈希码不同,则肯定对应的 2 个项目不同,但如果它们相等,则不能保证对应的 2 个项目相等。
所以这是正确的Equals
执行:
public bool Equals(MyClass item1, MyClass item2)
{
if(object.ReferenceEquals(item1, item2))
return true;
if(item1 == null || item2 == null)
return false;
return item1.MyString1.Equals(item2.MyString1) &&
item1.MyString2.Equals(item2.MyString2);
}
As 建议穿休闲裤 https://stackoverflow.com/questions/4340273/intersect-with-a-custom-iequalitycomparer-using-linq/4340318#4340318(期待我)代码如下:
var Default = new List<MyClass>
{
new MyClass{MyString1="A",MyString2="A",MyString3="-"},
new MyClass{MyString1="B",MyString2="B",MyString3="-"},
new MyClass{MyString1="X",MyString2="X",MyString3="-"},
new MyClass{MyString1="Y",MyString2="Y",MyString3="-"},
new MyClass{MyString1="Z",MyString2="Z",MyString3="-"},
};
var Good = new List<MyClass>
{
new MyClass{MyString1="A",MyString2="A",MyString3="+"},
new MyClass{MyString1="B",MyString2="B",MyString3="+"},
new MyClass{MyString1="C",MyString2="C",MyString3="+"},
new MyClass{MyString1="D",MyString2="D",MyString3="+"},
new MyClass{MyString1="E",MyString2="E",MyString3="+"},
};
var wantedResult = Good.Intersect(Default, new MyEqualityComparer())
.Union(Default, new MyEqualityComparer());
// wantedResult:
// A A +
// B B +
// X X -
// Y Y -
// Z Z -