c# - 如何格式化复杂的 linq 表达式？

Question

我有一种怪物的linq表达方式：

public static class HeaderOperators
{
    public static IDictionary<string, string> GetValues(IReadOnlyList<string> keys, IHeaderDictionary headers, string defaultValue)
    {
        return keys.Select(x => x.ToLower()).Intersect(headers.Keys.Select(x => x.ToLower()))
            .Select(k => new KeyValuePair<string, string>(k.ToLower(), headers[k.ToLower()]))
            .Union(keys.Select(x => x.ToLower()).Where(k => !headers.Keys.Select(x => x.ToLower()).Contains(k.ToLower())).Select(k => new KeyValuePair<string, string>(k.ToLower(), defaultValue)))
            .ToDictionary(p => p.Key.ToLower(), p => p.Value);
    }
}

是否有任何工具可以很好地格式化它以使其可读？

或者，也许有一种更易于管理的语法？

标签： c#.netlinq

Answer 1

我会将其拆分为更具可读性：

public static class HeaderOperators
{
    public static IDictionary<string, string> GetValues(IReadOnlyList<string> keys, IHeaderDictionary headers, string defaultValue)
    {
        var firstCollection = keys
            .Select(x => x.ToLower()).Intersect(headers.Keys.Select(x => x.ToLower()))
            .Select(k => new KeyValuePair<string, string>(k.ToLower(), headers[k.ToLower()]));

        var secondCollection = keys
            .Select(x => x.ToLower())
            .Where(k => !headers.Keys.Select(x => x.ToLower()).Contains(k.ToLower()))
            .Select(k => new KeyValuePair<string, string>(k.ToLower(), defaultValue));

        return
            firstCollection.Union(secondCollection).ToDictionary(p => p.Key.ToLower(), p => p.Value);
    }
}