LinQ

1 // LinQ 分页
2 listsearch = listsearch.Take(pageSize * pageIndex).Skip(pageSize * (pageIndex - 1)).ToList();

 1 //LinQ 按列去重
 2 listDistinct = list.Distinct(new ExampleComparer()).ToList();
 3 
 4 //去重类 （按FileName 去重）
 5 class ExampleComparer : IEqualityComparer<DistributeDownFileInfo>
 6     {
 7         public bool Equals(DistributeDownFileInfo x, DistributeDownFileInfo y)
 8         {
 9             if (Object.ReferenceEquals(x, y))
10                 return true;
11             if (Object.ReferenceEquals(x, null) || Object.ReferenceEquals(y, null)) return false;
12             return x.FileName == y.FileName;
13         }
14         public int GetHashCode(DistributeDownFileInfo example)
15         {
16             if (Object.ReferenceEquals(example, null)) return 0;
17             return example.FileName.GetHashCode();
18         }
19     }

1 //FindAll 匹配条件的所有元素
2 listDownTime = listDownTime.FindAll(b => b.FileName =="FileName").ToList();
3 //判断是否存在“FileName”
4 bool reuslt = listDownTime.FindAll(b => b.FileName == "FileName").Count < 1

1  //查询 like fileName
2   listAll = (from c in listAll where c.FileName.Contains(fileName) select c).ToList();

1 //查询 等于 
2 listAll = (from c in listAll where c.ClassID == Convert.ToInt32(classidList) select c).ToList();

1  //查询 or
2 string[] strArray = cascadeIPs.Split(‘,‘);
3  listAll = (from p in listAll where (strArray).Contains(p.CascadeIP) select p).ToList();

1 //查询 Between  and
2 listAll = (from u in listAll
3                            where
4                                u.DownTime > Convert.ToDateTime(startTime) && u.DownTime < Convert.ToDateTime(endTime)
5                                || u.DownErrTime > Convert.ToDateTime(startTime) && u.DownErrTime < Convert.ToDateTime(endTime)
6                                || u.RunTime > Convert.ToDateTime(startTime) && u.RunTime < Convert.ToDateTime(endTime)
7                                || u.RunErrTime > Convert.ToDateTime(startTime) && u.RunErrTime < Convert.ToDateTime(endTime)
8                            select u).ToList();