How to create LINQ Query from string?

by

You have a few options:

  • Use the the Dynamic Linq
    libraries to construct you queries on
    the fly. The best place to get
    started is by reading ScottGu’s blog
    entry    . However, I don’t think
    these libraries support the contains
    method in your example. Here is
    a blog post explaining how to add
    this support.

  • Directly execute SQL statements. Check out the MSDN docs for Linq to Sql or Linq to Entities.

    var _Products = myEntities.ExecuteStoreQuery<Product>
(@"SELECT * FROM Products WHERE [Name] In ('Item1', 'Item2')");

  • Use Linq’s composable behaviour. This might not be the most elegant solution but it works really well if you do not have too many options. You can just construct your query in multiple parts.

    var _Products = from product in myEntities.Products
                select product

_Products = from product in _Products 
            where product.Name.Contains(_Name)
            select product

if FilterByPrice {
    _Products = from product in _Products 
                where product.Price > 100 
                select product
}

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