using Expressions [modified]

[enginco]

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 <Func<T, bool>> expr1,
                                                        <Func<T, bool>> expr2)
    {
        var invokedExpr = Expression.Invoke(expr2, expr1.Parameters.Cast<Expression>());
        return Expression.Lambda<Func<T, bool>>
              (Expression.Or(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.And(expr1.Body, invokedExpr), expr1.Parameters);
    }
}

     public static Expression<Func<MyObj, bool>> AndKeyPredicate(MyObj o)
    {
        var predicate = PredicateBuilder.False<myobj>();
        foreach (string s in o.GetAndKeyItems()) // I need MyObj in here instead of "MyObj o" parameter
        {
            predicate = predicate.Or(p => MyText.All.Contains(s));
        }
        return predicate;
    }

IQueryable<myobj> _ob = xxx.AsQueryable();

var query = _ob.Where(AndKeyPredicate(xxx[0]));

I must take the each MyObj item for using in AndKeyPredicate parameter. we have 2 options: 1) var query = from y in _ob where AndKeyPredicate(y) select y; it doesn't work 2) we can get instance of MyObj from public static Expression<Func<T, bool>> AndKeyPredicate() predicate know p is a MyObj: predicate = predicate.Or(p => MyText.All.Contains(s)); but I have to use MyObj before //foreach (string s in o.GetAndKeyItems()) predicate = predicate.Or(p => MyText.All.Contains(s)); HOW?????? please help me

modified on Friday, July 18, 2008 8:14 AM