重写Distinct

添加类并继承`IEqualityComparer`，重写方法

public class DistinctComparer : IEqualityComparer<ActionInfo>
    {
    public bool Equals(ActionInfo x, ActionInfo y)
    {
    return x.ID == y.ID;
    }

    public int GetHashCode(ActionInfo obj)
    {
    return obj.ID.GetHashCode();
    }
    }

调用

 user_actions.Distinct<ActionInfo>(new DistinctComparer());