c#中的Distinct大多用于对数组去重，一般数组为基础的数据类型，例如 int,string.也可以用于对象去重，我们看看C#对Distinct方法的定义

Distinct对象数组去重复

public class ReceiptOwnerEqualityComparer : IEqualityComparer<ReceiptOwner>
{
    public bool Equals(ReceiptOwner x, ReceiptOwner y)
    {
        return x.ReceiptId == y.ReceiptId
            && x.UserName == y.UserName
            && x.SchoolName == y.SchoolName
            && x.DepartmentName == y.DepartmentName;
    }

    public int GetHashCode(ReceiptOwner table)
    {
        var key = $"{table.ReceiptId}{table.UserName}{table.SchoolName}{table.DepartmentName}";
        return key.GetHashCode();
    }
}

继承IEqualityComparer接口必须实现 Equals 和 GetHashCode 方法

我们比较的时候，传入一个 ReceiptOwnerEqualityComparer 的实体即可：

.Distinct(new ReceiptOwnerEqualityComparer()).ToList();

参考

https://blog.csdn.net/lishuangquan1987/article/details/76096022