如何在 linq 查询 vb.net 中比较两个数组列表项

Question

我有两个查询（qry1 返回 [a1],[a2]；qry2 返回 [a1],[a2],[a3]）。所以我想比较这两个查询。如果它们不相等，则执行某些功能。以下是我正在尝试的查询。我不想与“计数”运算符进行比较。

Dim Qry1 = (From x In db1.Approvals _
        Where x.ID = tId _
        And x.APPROVALID = GetRqstID(thisId) _
        Select x.APPROVERID).ToList()


 Dim Qry2 = (From x In db.Resources _
             Join y In db.Users On x.USER_ID Equals y.USER_ID _
             Where x.ID = tskIdIn _
             And x.TYPE = rsrcType _
             Order By y.FIRST_NAME _
            Select x.USER_ID).ToList()


 If ((Qry1.ToArray) <> (Qry2.ToArray)) Then
---
---
 End If

Answer 1

if (Qry1.Count() != Qry2.Count() || 
    Qry1.Except(Qry2).Count() > 0 ||
    Qry2.Except(Qry1).Count() > 0)  
 // not the same.

我首先进行计数检查，因为短路会加快大多数情况。如果您正在执行其他两个，则不需要。

https://msdn.microsoft.com/en-us/library/bb300779%28v=vs.110%29.aspx

Answer 2

Linq Intersect 将是最佳候选。

int[] id1 = { 44, 26, 92, 30, 71, 38 };
int[] id2 = { 39, 59, 83, 47, 26, 4, 30 };

IEnumerable<int> both = id1.Intersect(id2);

foreach (int id in both)
    Console.WriteLine(id);

/*
 This code produces the following output and means you have some element repeating on both array instance. If there is no matching element then you can perform the operation that you wanted.:

 26
 30
*/