我试图在运行时生成一个简单的Lambda表达式,但一直没有成功……大概像这样:
var result = queryableData.Where(item => item.Name == "Soap")
这是我的示例类和一个可查询的fixture:
public class Item
{
public int Id { get; set; }
public string Name { get; set; }
}
IQueryable<Item> queryableData = ...;
然后我在运行时生成一个lambda表达式,正确的代码如下:
//"item" in "item =>..."
var item = Expression
.Parameter(typeof(Item), "item");
//property of my item, this is "item.Name"
var prop = Expression
.Property(item, "Name");
//then "Soap" in '... => item.Name=="Soap"'
var value = Expression.Constant("Soap");
//equality expression "==" in my primer
var equals = Expression.Equal(prop, value);
//then lambda
var lambda = Expression.Lambda<Func<Item, bool>>(equals, item);
//and here are the results
var results = queryableData.Where(lambda);
非常感谢dtb的建议!