var multiColQuery = from line in strs let elements = line.Split(',') let scores = elements.Skip(1) select (from str in scores select Convert.ToInt32(str)); // Execute the query and cache the results to improve // performance. // ToArray could be used instead of ToLi...
stringstartFolder ="""C:\Program Files\dotnet\sdk""";// Or// string startFolder = "/usr/local/share/dotnet/sdk";DirectoryInfo dir =newDirectoryInfo(startFolder);varfileList = dir.GetFiles("*.*", SearchOption.AllDirectories);stringsearchTerm ="change";varqueryMatchingFiles =from...
from Type Item in Items 下图演示了from子句的语法。类型说明符是可选的。可以有任意多个join子句。 尽管LINQ的from子句和foreach语句非常相似,但主要不同点如下: foreach语句命令式地指定了从第一个到最后一个按顺序地访问集合中的项。而from子句则声明式地规定集合中的每个项都要被访问,但并没有假定以什么样...
linq .Net Core，合并两个列表，删除无效条目并保留原始列表中的值使用一个通用的IEqualityComparer，它的...
stringstartFolder ="""C:\Program Files\dotnet\sdk""";// Or// string startFolder = "/usr/local/share/dotnet/sdk";varfileList = Directory.GetFiles(startFolder,"*.*", SearchOption.AllDirectories);varfileQuery =fromfileinfileListletfileLen =newFileInfo(file).LengthwherefileLen >0sel...
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var query = from x in ctx.TableName select x).ToList(); sfDataGrid.DataSource = query; } Then, when user selects one or multiple rows, the Delete button is Visible and when User clicks on it, it removes all rows. So far, I have code to remove only one row, but need to allow...
FirstReturns first item in list. LastReturns last item in list. Range (static)Creates list of numbers, within a specified range.start,length AddAdds element to list.item AddRangeAdds each item in given list.items RemoveAtRemoves item from list by index.index ...
可选的from…let…where部分是查询主体的第一部分,可以由任意数量的3个子句来组合–from子句、let子句和where子句。 from子句 查询表达式从必需的from子句开始,后面跟查询主体。主体本身可以从任何数量的其他from子句开始,每个from子句都指定了一个额外的源数据集合并引入了要在之后运算的迭代变量,所有from子句的语法和...
ToList<TSource>(IEnumerable<TSource>) Creates aList<T>from anIEnumerable<T>. ToLookup<TSource,TKey>(IEnumerable<TSource>, Func<TSource,TKey>, IEqualityComparer<TKey>) Creates aLookup<TKey,TElement>from anIEnumerable<T>according to a specified key selector function and key comparer. ...