c# predicate builder, useful for constructing linq predicates

ExpressionWhereFinder.cs

internal class ExpressionWhereFinder : ExpressionVisitor
    {
        private readonly IList<MethodCallExpression> _whereExpressions = new List<MethodCallExpression>();

        public IEnumerable<MethodCallExpression> GetWhere(Expression expression)
        {
            Visit(expression);
            return _whereExpressions;
        }

        protected override Expression VisitMethodCall(MethodCallExpression expression)
        {
            if (expression.Method.Name == "Where")
            {
                _whereExpressions.Add(expression);
            }

            Visit(expression.Arguments[0]);
            return expression;
        }
    }

PredicateBuilder.cs

namespace MyApp.Linq
{
    using System;
    using System.Linq;
    using System.Linq.Expressions;

    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);
        }
    }

}