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如何在select查询中添加函数

select function linq c#

Timothy055 · 技术社区 · 16 年前

select new FeedResource
{ 
   Title = (string)details.Element("title"),  
   Host = (string)details.Element("link"),   
   Description = (string)details.Element("description"), 
   PublishedOn = (DateTime?)details.Element("pubDate"), 
   Generator = (string)details.Element("generator"),  
  Language = (string)details.Element("language")
}

在上面的代码中,我想将类型转换值传递给另一个函数, 例子

Description = getValidDescription((string) details.Element("description"))

注意:类型转换需要处理null值(即在“description”没有值的情况下),它(XElement)可以完美地处理null。

1 回复 | 直到 12 年前

Marc Gravell 16 年前

为我工作很好;错误消息是什么?例子:

// doesn't have to be static - just simpler for my test
static string getValidDescription(string description)
{
    // handle nulls safely (could return a default here)
    if (description == null) return null;
    // for example only...
    return CultureInfo.CurrentCulture.TextInfo
        .ToTitleCase(description);
}

var qry =
    from details in doc.Root.Elements("detail")
    select new FeedResource
    {
        Title = (string)details.Element("title"),
        Host = (string)details.Element("link"),
        Description = getValidDescription((string) details.Element("description")),
        PublishedOn = (DateTime?)details.Element("pubDate"),
        Generator = (string)details.Element("generator"),
        Language = (string)details.Element("language")
    };

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