只需使用普通布尔运算符& &和||:
XDocument db = XDocument.Load(xmlPath);
var query = (from vals in db.Descendants("Customer")
where (textbox1.Text != "" &&
vals.Element("CustomerID") == Convert.ToInt32(textbox1.Text)) ||
(textbox2.Text != "" && vals.Element("Name") == textbox2.Text)
select vals).ToList();
这是原代码的仅仅是直接翻译 - 但我认为你会想从vals.Element("CustomerID")
强制转换为int
,你真的不想要转换012我敢肯定,每次迭代都会有。您还需要将“名称”XElement
转换为字符串。这个怎么样:
int? customerId = null;
if (textbox1.Text != "")
{
customerId = int.Parse(textbox1.Text);
}
XDocument db = XDocument.Load(xmlPath);
var query = (from vals in db.Descendants("Customer")
where (customerId != null &&
(int) vals.Element("CustomerID") == customerId) ||
(textbox2.Text != "" &&
(string) vals.Element("Name") == textbox2.Text)
select vals).ToList();
或者,你可以分开查询的两部分和“联合”结果在一起。或者 - 最好IMO - 你可以更动态地建立查询:
var query = db.Descendants("Customer");
if (textbox1.Text != null)
{
int customerId = int.Parse(textbox1.Text);
query = query.Where(x => (int) x.Element("CustomerID") == customerId);
}
if (textbox2.Text != null)
{
query = query.Where(x => (string) x.Element("Name") == textbox2.Text);
}
List<XElement> results = query.ToList();
神奇再次乔恩。正如你在第二个选项中提到的那样,我已经列出了一些值,只是使用上面的代码来使事情变得更简单。再一次非常感谢你! – 2010-04-14 08:55:10