How to order by multiple columns using VB.Net lamb

2019-02-16 06:29发布

I've done a brief search of this site, and googled this, but can't seem to find a good example. I'm still trying to get my head around the whole "Lambda Expressions" thing.

Can anyone here give me an example ordering by multiple columns using VB.Net and Linq-to-SQL using a lambda expression?

Here is my existing code, which returns an ordered list using a single-column to order the results:

Return _dbContext.WebCategories.OrderBy(Function(c As WebCategory) c.DisplayOrder).ToList

Note: The WebCategory object has a child WebPage object (based on a foreign key). I'd like to order by WebPage.DisplayOrder first, then by WebCategory.DisplayOrder.

I tried chaining the order bys, like below, and though it compiled and ran, it didn't seem to return the data in the order I wanted.

Return _dbContext.WebCategories.OrderBy(Function(c As WebCategory) c.DisplayOrder).OrderBy(Function(c As WebCategory) c.WebPage.DisplayOrder).ToList

Thanks in advance.

2条回答
时光不老,我们不散
2楼-- · 2019-02-16 06:48

You should use ThenBy like this:

Return _dbContext.WebCategories.OrderBy(Function(c As WebCategory) c.DisplayOrder) _
                               .ThenBy(Function(c As WebCategory) c.WebPage.DisplayOrder) _
                               .ToList()
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萌系小妹纸
3楼-- · 2019-02-16 06:56

I found this MSDN article in a quick Google search. I guess what your looking for is this:

Return _dbContext.WebCategories.OrderBy(Function(c As WebCategory) c.DisplayOrder). _
ThenBy(Function(c As WebCategory) c.WebPage.DisplayOrder).ToList
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