1、List<T>之間的轉換
((List<object>)sourceList).Select(n => (T)n).ToList();
2、DataTable中的某一列轉為List<T>
(from r in dataTable.AsEnumerable() select r.Field<string>("datname")).ToList<string>();
(from r in dataTable.AsEnumerable() select r.Field<int>("fid")).ToList<int>()
3、List獲取最后一個元素(單個)
string str = lst[lst.Length-1];
切片語法糖:string str = lst[^1];
4、List獲取元素第一到第三的元素
var temp = new string[] { lst[1], lst[2], lst[3] };
var temp = lst.Skip(1).Take(3).ToArray();
切片語法糖:var temp = lst[1..4];
5、List中的某一列轉為逗號分割的string
List<long> ids = new List<long> { 1, 2, 3 }; string str = string.Join(",", ids.Select(q => "'" + q + "'"));
6、List轉為Dictionary
List<RegularFileInfo> _RegularFilesList; List<RegularFolderInfo> _RegularFolderList; new Dictionary<string, List<RegularFileInfo>> tempDic = _RegularFolderList.ToDictionary(key => key.FolderName,
FieldsTable => _RegularFilesList.FindAll(n => n.FolderName == FieldsTable.FolderName));
7、獲取兩個List的重復元素
List<string> repeatList = shpfileldsList.Where(p => list.Any(p2 => p.ToLower() == p2)).ToList();
8、