本文取出来做你想要什么:
http://www.albahari.com/nutshell/predicatebuilder.aspx
这就像一个梦。我基本上是剪切和粘贴自己的代码,并得到这个回来(当然是我自己的数据方案):
SELECT [t0].[Id], [t0].[DateCreated], [t0].[Name] ...
FROM [dbo].[Companies] AS [t0]
WHERE ([t0].[Name] LIKE @p0) OR ([t0].[Name] LIKE @p1)
这是我跑了概念证明代码:
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Linq.Expressions;
namespace PredicateTest
{
class Program
{
static void Main(string[] args)
{
DataClasses1DataContext dataContext = new DataClasses1DataContext();
Program p = new Program();
Program.SearchCompanies("test", "test2");
var pr = from pi in dataContext.Companies.Where(Program.SearchCompanies("test", "test2")) select pi;
}
DataClasses1DataContext dataContext = new DataClasses1DataContext();
public static Expression<Func<Company, bool>> SearchCompanies(
params string[] keywords)
{
var predicate = PredicateBuilder.False<Company>();
foreach (string keyword in keywords)
{
string temp = keyword;
predicate = predicate.Or(p => p.Name.Contains(temp));
}
return predicate;
}
}
public static class PredicateBuilder
{
public static Expression<Func<T, bool>> True<T>() { return f => true; }
public static Expression<Func<T, bool>> False<T>() { return f => false; }
public static Expression<Func<T, bool>> Or<T>(this Expression<Func<T, bool>> expr1,
Expression<Func<T, bool>> expr2)
{
var invokedExpr = Expression.Invoke(expr2, expr1.Parameters.Cast<Expression>());
return Expression.Lambda<Func<T, bool>>
(Expression.OrElse(expr1.Body, invokedExpr), expr1.Parameters);
}
public static Expression<Func<T, bool>> And<T>(this Expression<Func<T, bool>> expr1,
Expression<Func<T, bool>> expr2)
{
var invokedExpr = Expression.Invoke(expr2, expr1.Parameters.Cast<Expression>());
return Expression.Lambda<Func<T, bool>>
(Expression.AndAlso(expr1.Body, invokedExpr), expr1.Parameters);
}
}
}
我d建议去网站查看代码和解释。
(我离开第一个答案,因为它工作得很好,如果你需要一个在报表)
这肯定应该工作 – 2009-02-04 17:24:46