ASP.NET

(o => o.LognName == name) 

Expression<Func<Users_UserAccount, bool>> whereLogonName = LinqExtender.DynamicLinq.BuildOrTree<Users_UserAccount, string>(LogonName, UserAccount => UserAccount.LogonName);

(o => o.LognName == name && o.LogonPW == "12345") //dumb pw

Expression.Or
Expression.And

public static Expression<Func<TValue, bool>> BuildOrTree<TValue, TCompareAgainst>(
        IEnumerable<TCompareAgainst> wantedItems,
        Expression<Func<TValue, TCompareAgainst>> convertBetweenTypes)
        {
            ParameterExpression inputParam = convertBetweenTypes.Parameters[0];

            Expression binaryExpressionTree = BuildBinaryOrTree(wantedItems.GetEnumerator(), convertBetweenTypes.Body, null);

            return Expression.Lambda<Func<TValue, bool>>(binaryExpressionTree, new[] { inputParam });
        }

private static Expression BuildBinaryOrTree<T>(
        IEnumerator<T> itemEnumerator,
        Expression expressionToCompareTo,
        Expression expression)
        {
            if (itemEnumerator.MoveNext() == false)
                return expression;

            ConstantExpression constant = Expression.Constant(itemEnumerator.Current, typeof(T));
            BinaryExpression comparison = Expression.Equal(expressionToCompareTo, constant);

            BinaryExpression newExpression;

            if (expression == null)
                newExpression = comparison;
            else
                newExpression = Expression.OrElse(expression, comparison);

            return BuildBinaryOrTree(itemEnumerator, expressionToCompareTo, newExpression);
        }

.yakoutb
{
    font-family: 'Yakout W20 Bold';
}