c# - 如何使用 LINQ 从 DataTable 中获取不同的有序名称列表？

Question

我有DataTable一个Name专栏。我想生成按字母顺序排列的唯一名称的集合。以下查询忽略order by子句。

var names =
    (from DataRow dr in dataTable.Rows
    orderby (string)dr["Name"]
    select (string)dr["Name"]).Distinct();

为什么不orderby强制执行？

Answer 1

问题是 Distinct 运算符不同意它将保持值的原始顺序。

所以你的查询需要像这样工作

var names = (from DataRow dr in dataTable.Rows
             select (string)dr["Name"]).Distinct().OrderBy( name => name );

Answer 2

To make it more readable and maintainable, you can also split it up into multiple LINQ statements.

1. First, select your data into a new list, let's call it x1, do a projection if desired
2. Next, create a distinct list, from x1 into x2, using whatever distinction you require
3. Finally, create an ordered list, from x2 into x3, sorting by whatever you desire

Answer 3

var sortedTable = (from results in resultTable.AsEnumerable()
select (string)results[attributeList]).Distinct().OrderBy(name => name);

Answer 4

尝试以下方法：

dataTable.Rows.Cast<DataRow>().select(dr => dr["Name"].ToString()).Distinct().OrderBy(name => name);

Answer 5

尝试以下

var names = (from dr in dataTable.Rows
             select (string)dr["Name"]).Distinct().OrderBy(name => name);

这应该可以满足您的需要。

Answer 6

你可以使用类似的东西：

dataTable.Rows.Cast<DataRow>().GroupBy(g => g["Name"]).Select(s => s.First()).OrderBy(o => o["Name"]);

Answer 7

抽象：所有的答案都有一些共同点。

OrderBy 需要是最后的操作。