鉴于以下情况QueryOver
:
UserProfile userProfileAlias = null;
Pegfile pegfileAlias = null;
var q = Session.QueryOver(() => pegfileAlias)
.JoinAlias(() => pegfileAlias.UserProfile, () => userProfileAlias);
我想通过交换使以下语句动态化
q = q.OrderBy(() => userProfileAlias.Forename).Asc;
(OrderBy(Expression<Func<object>>
或 ( OrderBy(Expression<Func<T, object>>)
)
和
q = q.OrderBy(GetMemberExpression(userProfileAlias, "Forename")).Asc;
我从另一个帖子借来得到
private Expression<Func<object>> GetMemberExpression(UserProfile instance, string propertyName)
{
var arg = Expression.Constant(instance, typeof(UserProfile));
var body = Expression.Convert(Expression.PropertyOrField(arg, propertyName), typeof(UserProfile));
var lambda = Expression.Lambda<Func<object>>(body);
return lambda;
}
但这不起作用,我得到:
System.InvalidOperationException
No coercion operator is defined between types 'System.String' and 'Pegfect.Domain.PegDudes.UserProfile'.
我想我可能需要匹配以下信号:
OrderBy(Expression<Func<UserProfile,object>>)
如何GetMemberExpression
变成退货?