LINQ铸造用Data.DataTableCollection [英] LINQ casting with a Data.DataTableCollection

问题描述

我有我使用到Data.DataTable由列数排序如下VB.NET code。

I have the following VB.NET code that I am using to sort a Data.DataTable by column count.

For Each dtTarget As Data.DataTable In _
    From x In Target.Tables _
    Where DirectCast(x, Data.DataTable).Rows.Count > 0 _
    Order By DirectCast(x, Data.DataTable).Columns.Count
...
Next

有一种方法，以指示x被一个Data.DataTable无需它被引用（在这种情况下，两次）每次D​​irectCast它在LINQ查询？

Is there a way to indicate that x is a Data.DataTable without having to DirectCast it each time it is referenced (twice in this case) in the LINQ query?

推荐答案

是这样的：

Target.Tables.Cast<Data.DataTable>()

，然后让你的那个查询。而且你应该正确地重构你code成几行，以使其更具可读性。

and then make your query of that. And you should properly refactor you code into several lines to make it more readable.

（这是C＃ - 但我把它翻译，2秒）

(this is C# - but I will translate it, 2 sec)

翻译：

Dim query = From x In Target.Tables.Cast(Of Data.DataTable)() _
 Where x.Rows.Count > 0 _
 Order By x.Columns.Count _
 Select x

For Each dtTarget As var In query
   ...
Next

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