如何使用 linq- c# 将 XML 元素值转换为 int
本文关键字:转换 int 元素 XML 何使用 linq- | 更新日期: 2023-09-27 18:31:16
我正在尝试从我的 XML 元素中获取值并使用 linq 命令将其转换为整数,以便我可以使用它做一些数学方程。
到目前为止,我就是这样尝试的:
private void buttonTab4Mod1Calculate_Click(object sender, EventArgs e)
{
var document = XDocument.Load(workingDir + @"'Level4.xml");
var assessmentOneWeight = from d in document.Descendants("moduleTitle")
where d.Value == (String)comboBoxTab4Mod8.SelectedItem
select d.Parent.Element("assessmentOneWeight").Value;
int a = 0;
foreach (var item in assessmentOneWeight)
{
a = Convert.ToInt32(item);
}
MessageBox.Show(a.ToString());
}
但由于某种原因,该值仍为 0。
这是我的 xml 文件:
<?xml version="1.0" encoding="utf-8" ?>
<SoftwareEngineering>
<Module>
<moduleCode>ECSE401</moduleCode>
<moduleTitle>Programming Methodology</moduleTitle>
<credits>15</credits>
<assessmentOne>Coursework</assessmentOne>
<assessmentOneWeight>40</assessmentOneWeight>
<assessmentTwo>Coursework</assessmentTwo>
<assessmentTwoWeight>40</assessmentTwoWeight>
<assessmentThree>Test</assessmentThree>
<assessmentThreeWeight>20</assessmentThreeWeight>
</Module>
<Module>
<moduleCode>ECSC404</moduleCode>
<moduleTitle>Computer Systems Fundamentals</moduleTitle>
<credits>15</credits>
<assessmentOne>Test1</assessmentOne>
<assessmentOneWeight>30</assessmentOneWeight>
<assessmentTwo>Test2</assessmentTwo>
<assessmentTwoWeight>30</assessmentTwoWeight>
<assessmentThree>Test3</assessmentThree>
<assessmentThreeWeight>40</assessmentThreeWeight>
</Module>
<Module>
<moduleCode>EBSY401</moduleCode>
<moduleTitle>Information and Data Modelling</moduleTitle>
<credits>15</credits>
<assessmentOne>Test</assessmentOne>
<assessmentOneWeight>25</assessmentOneWeight>
<assessmentTwo>Coursework1</assessmentTwo>
<assessmentTwoWeight>10</assessmentTwoWeight>
<assessmentThree>Coursework2</assessmentThree>
<assessmentThreeWeight>35</assessmentThreeWeight>
<assessmentFour>Coursework3</assessmentFour>
<assessmentFourWeight>30</assessmentFourWeight>
</Module>
<Module>
<moduleCode>ECSC405</moduleCode>
<moduleTitle>Software Development Principles</moduleTitle>
<credits>15</credits>
<assessmentOne>Test1</assessmentOne>
<assessmentOneWeight>30</assessmentOneWeight>
<assessmentTwo>Coursework</assessmentTwo>
<assessmentTwoWeight>40</assessmentTwoWeight>
<assessmentThree>Test2</assessmentThree>
<assessmentThreeWeight>30</assessmentThreeWeight>
</Module>
<Module>
<moduleCode>ECSC407</moduleCode>
<moduleTitle>Web Technology</moduleTitle>
<credits>15</credits>
<assessmentOne>Tutorials</assessmentOne>
<assessmentOneWeight>20</assessmentOneWeight>
<assessmentTwo>Coursework</assessmentTwo>
<assessmentTwoWeight>20</assessmentTwoWeight>
<assessmentThree>Exam</assessmentThree>
<assessmentThreeWeight>60</assessmentThreeWeight>
</Module>
<Module>
<moduleCode>ECSC409</moduleCode>
<moduleTitle>Software Engineering Principles</moduleTitle>
<credits>15</credits>
<assessmentOne>Coursework1</assessmentOne>
<assessmentOneWeight>40</assessmentOneWeight>
<assessmentTwo>Coursework2</assessmentTwo>
<assessmentTwoWeight>30</assessmentTwoWeight>
<assessmentThree>Coursework3</assessmentThree>
<assessmentThreeWeight>30</assessmentThreeWeight>
</Module>
<Module>
<moduleCode>ECSC408</moduleCode>
<moduleTitle>Mathematics for Computing</moduleTitle>
<credits>15</credits>
<assessmentOne>Coursework</assessmentOne>
<assessmentOneWeight>50</assessmentOneWeight>
<assessmentTwo>Exam</assessmentTwo>
<assessmentTwoWeight>50</assessmentTwoWeight>
</Module>
<Module>
<moduleCode>EBSY400</moduleCode>
<moduleTitle>Communication and Learning Skills</moduleTitle>
<credits>15</credits>
<assessmentOne>Coursework</assessmentOne>
<assessmentOneWeight>30</assessmentOneWeight>
<assessmentTwo>Coursework</assessmentTwo>
<assessmentTwoWeight>70</assessmentTwoWeight>
</Module>
</SoftwareEngineering>
将非常感谢一些帮助。
只需将XElement
投射到 int
:
private void buttonTab4Mod1Calculate_Click(object sender, EventArgs e)
{
var document = XDocument.Load(workingDir + @"'Level4.xml");
string selectedItem = (string) comboBoxTab4Mod8.SelectedItem;
var assessmentOneWeight = from d in document.Descendants("moduleTitle")
where (string) d == selectedItem
select (int) d.Parent.Element("assessmentOneWeight");
foreach (int item in assessmentOneWeight)
{
MessageBox.Show(item.ToString());
}
}
请注意,您也可以强制转换为int?
,当引用是XElement
时,其工作方式相同,但是如果您将空引用转换为int?
则会返回一个空值 - 如果您不知道是否有相应的元素,这会很有帮助。
XElement
有很多显式转换,XAttribute
- 它们使生活变得更容易。
我很确定您的assessmentOneWeight
集合不包含单个值,因为在 XML 中找不到comboBoxTab4Mod8.SelectedItem
的值。
因此你总是得到0
,因为a
是用0
初始化的。
顺便说一句:我强烈建议你改进你的代码。
循环访问 <Module>
元素而不是 <moduleTitle>
元素。这更有意义,因为您需要此元素的数据(即<assessmentOneWeight>
)
直接在 LINQ 语句中强制转换 <assessmentOneWeight
> 的值,如下所示:
var assessmentOneWeight =
from d in document.Descendants("moduleTitle")
where d.Value == (String)comboBoxTab4Mod8.SelectedItem
select int.Parse(d.Parent.Element("assessmentOneWeight").Value);
您的foreach
设计不佳,因为它仅采用集合中找到的最后一个值。如果确实需要该值,请使用 LINQ 的强大功能并仅选择该值。