Given the following
鉴于以下内容
Expression<Func<T,bool>> matchExpression;
How can i create another expression that is a 'not' of the existing one.
如何创建另一个与现有表达式“不”的表达式。
i have tried
我努力了
Expression<Func<T, bool>> func3 = (i) => !matchExpression.Invoke(i);
but this is not supported by the entity framework...
但实体框架不支持这个......
Regards
问候
1 个解决方案
#1
10
You have to recreate a new lambda, and negate the body of the original one:
你必须重新创建一个新的lambda，并否定原始lambda的主体：
Expression<Func<T, bool>> not = Expression.Lambda<Func<T, bool>> (
Expression.Not (matchExpression.Body),
matchExpression.Parameters [0]);
#1
10
You have to recreate a new lambda, and negate the body of the original one:
你必须重新创建一个新的lambda，并否定原始lambda的主体：
Expression<Func<T, bool>> not = Expression.Lambda<Func<T, bool>> (
Expression.Not (matchExpression.Body),
matchExpression.Parameters [0]);