OrderBy is not translated into SQL when passing a selector function

问题

When I execute:

var t = db.Table1.OrderBy(x => x.Name).ToList();

In SQL profiler, this is the translated SQL:

SELECT 
[Extent1].[ID] AS [ID], 
[Extent1].[Name] AS [Name]
FROM [dbo].[Table1] AS [Extent1]
ORDER BY [Extent1].[Name] ASC

Which is correct.

However, if I pass a selector function to OrderBy:

Func<Table1, string> f = x => x.Name;
var t = db.Table1.OrderBy(f).ToList();

The translated SQL is:

SELECT 
[Extent1].[ID] AS [ID], 
[Extent1].[Name] AS [Name]
FROM [dbo].[Table1] AS [Extent1]

The orderby is totally not translated.

What's the problem? They are the same lambda function, the only difference is in the 2nd case, it is first assigned to a variable.

回答1:

Cause in a IQueryable world, you need an Expression<Func<TModel, TValue>> as the OrderBy's extension parameter, not a Func<TModel, TValue>

http://msdn.microsoft.com/en-us/library/system.linq.queryable.orderby

来源：https://stackoverflow.com/questions/12210799/orderby-is-not-translated-into-sql-when-passing-a-selector-function