Linq to Entities过滤实体动态/强类型

I am binding a Winforms Grid to an entity. (For reasons I won't go into here it must be bound to the entity, not the result a query) The code is as follows:

我正在将Winforms Grid绑定到实体。 (由于我不会进入这里的原因,它必须绑定到实体,而不是查询的结果)代码如下:

grid.DataSource = myEntities.entityName.Where("it.field = " & field)

It works, but it obviously isn't strongly typed. Is there a way to define the Where clause of an entity using a strongly typed notation?

它有效,但显然不是强类型。有没有办法使用强类型表示法定义实体的Where子句?

1 个解决方案

#1

Have you tried to use a lambda expression?

你试过使用lambda表达式吗?

grid.DataSource = myEntities.Customers.Where(c => c.Name == "Bob");

or in VB:

或者在VB中:

grid.DataSource = myEntities.Customers.Where(Function(c) c.Name = "Bob")

If it has to be dynamic then you might want to look at building a custom Expression Tree. For a tutorial on the basics of Expression Trees see this blog http://blogs.msdn.com/charlie/archive/2008/01/31/expression-tree-basics.aspx

如果它必须是动态的,那么您可能希望查看构建自定义表达式树。有关Expression Trees基础知识的教程,请参阅此博客http://blogs.msdn.com/charlie/archive/2008/01/31/expression-tree-basics.aspx

This blog shows a good example of sorting. http://weblogs.asp.net/davidfowler/archive/2008/12/11/dynamic-sorting-with-linq.aspx

这篇博客展示了一个很好的排序示例。 http://weblogs.asp.net/davidfowler/archive/2008/12/11/dynamic-sorting-with-linq.aspx

#1