如何检查XML文件中的文本框输入是否可用？但是我的代码没有显示任何结果

This is the code I used.

这是我使用的代码。

private void button1_Click(object sender, EventArgs e)

    {
        XDocument doc = XDocument.Load("XMLDatabase.xml");
        var NumberExist = doc.Descendants("Users")
                        .Any(x => (string)x.Element("ID") == txtId.Text);

        if (NumberExist)
        {
            MessageBox.Show("Number already exist");
        } 
    }

My Xml:

<?xml version="1.0" encoding="UTF-8" standalone="yes"?> 
    <Users> 
        <User Name="aa" Occupation="dd" Date_Of_Birth="123456" NIC="123123" ID="79461" /> 
        <User Name="Ali Rasheed" Occupation="Student" Date_Of_Birth="111694" NIC="4550246607037" ID="12661" /> 
        <User Name="Asif Rasheed" Occupation="Civil Engineer" Date_Of_Birth="241190" NIC="4550346603073" ID="90939" /> 
    </Users>

1 个解决方案

#1

First, there is no ID element in Users, It belongs to User.

首先,用户中没有ID元素,属于User。

Second, ID is not an Element, It's an Attribute.

其次,ID不是元素,它是属性。

Therefore, you should change your code like this:

因此,您应该像这样更改代码:

var NumberExist = doc.Descendants("User")
                .Any(x => (string)x.Attribute("ID") == txtId.Text);

#1