Question

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.

Answer 1

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

Answer 2

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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