UWP ListView数据绑定

DearXuan

发布于 2022-01-19 18:45:47

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发布于 2022-01-19 18:45:47

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在制作UWP个人项目时需要用到数据绑定，网上的教程大都不全，特此记录下自己使用的方法。

绑定源

指定一个类用来保存数据，以我自己的项目为例，需要定义“邮件”类。

MailSystem_UWP.Bean.Email

namespace MailSystem_UWP.Bean
{
    /*
     * mail_table:
     *      id:int
     *      sender:varchar(10)
     *      receiver:varchar(10)
     *      title:varchar(50)
     *      content:varchar(500)
     *      time:datetime
     *      state:int
     */
    public class Email
    {
        public enum STATE
        {
            Delivery = 0,//送达
            RecipientNotFound = 1,//找不到收件人
            Deleted = 2//已被删除
        }
        public int id { get; set; }
        public string sender { get; set; }
        public string receiver { get; set; }
        public string title { get; set; }
        public string content { get; set; }
 
        public DateTime time { get; set; }
        public STATE state { get; set; }
 
        public Email() { }
 
        public Email(MySqlDataReader reader)
        {
            LoadFromReader(reader);
        }
 
        /// <summary>
        /// 从MySqlDataReader获取User实例
        /// </summary>
        /// <param name="reader">MySqlDataReader实例</param>
        public void LoadFromReader(MySqlDataReader reader)
        {
            id = reader[0].ToString().ToInt();
            sender = reader[1].ToString();
            receiver = reader[2].ToString();
            title = reader[3].ToString();
            content = reader[4].ToString();
            time = reader.GetDateTime(5);
            state = (STATE)reader[6].ToString().ToInt();
        }
 
        /// <summary>
        /// 获取概要，用于显示在TextBlock中
        /// </summary>
        /// <returns>string类型:标题+"\n"+概要</returns>
        public string GetDescription()
        {
            return (content.Length <= Value.UserForm.DESCRIPTION_MAX_LENGTH
                ? content
                : content.Substring(0, Value.UserForm.DESCRIPTION_MAX_LENGTH) + "...")
                + "\n";
        }
    }
}

为绑定源定义集合

private static ObservableCollection<Email> data = new ObservableCollection<Email>();

当UWP进行了页面跳转，即使使用GoBack()来返回，原页面也会重新加载，因此建议使用静态类来避免数据丢失，并且修改集合时也不需要获取MainPage的实例

创建绑定

在xaml文件头定义命名空间

由于我的Email类在MailSystem_UWP.Bean下，因此定义该命名空间为local

xmlns:local="using:MailSystem_UWP.Bean"

在xaml文件的Page标签内定义模板

<Page.Resources>
    <DataTemplate x:Key="EMAIL" x:DataType="local:Email">
        <Grid Height="80" Margin="0,0,0,0">
            <TextBlock HorizontalAlignment="Left" Margin="10,10,0,0" Text="{x:Bind title}" TextWrapping="Wrap" VerticalAlignment="Top" FontWeight="Bold"/>
            <TextBlock Margin="0,10,10,0" Text="{x:Bind time}" TextWrapping="Wrap" VerticalAlignment="Top" HorizontalAlignment="Right" Width="auto" FontWeight="Normal"/>
            <TextBlock HorizontalAlignment="Left" Margin="10,34,0,10" Text="{x:Bind content}" TextWrapping="Wrap" Width="408"/>
        </Grid>
    </DataTemplate>
</Page.Resources>

{x:Bind name}指向绑定源的name属性，你需要实现name的get和set方法，像这样

public int id { get; set; }

对于非字符串变量，例如System.DateTime，系统会自动调用toString()

DataTemplate内即为数据模板，ListView会根据模板逐一添加控件

现在为ListView加上ItemTemplate属性

<ListView 
    x:Name="listView" 
    ItemTemplate="{StaticResource EMAIL}" 
    HorizontalAlignment="Left" 
    Width="325" 
    Margin="0,55,0,0" 
    Background="White" 
    SelectionChanged="onSelectionChange" 
    IsItemClickEnabled="True" 
    ItemClick="onItemClick"/>

在MainPage的构造函数里绑定数据源

public MainPage()
{
    this.InitializeComponent();
    listView.ItemsSource = data;
}

添加数据

直接为data添加数据，ListView中会自动更新

data.Clear();
for(int i = 0; i < emails.Count; i++)
{
    //emails是ArrayList<Email>的实例
    data.Add(emails[i]);
}

完整代码

MailSystem.Bean.Email

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using MySql.Data.MySqlClient;
using MailSystem_UWP.Support;
 
namespace MailSystem_UWP.Bean
{
    /*
     * mail_table:
     *      id:int
     *      sender:varchar(10)
     *      receiver:varchar(10)
     *      title:varchar(50)
     *      content:varchar(500)
     *      time:datetime
     *      state:int
     */
    public class Email
    {
        public enum STATE
        {
            Delivery = 0,//送达
            RecipientNotFound = 1,//找不到收件人
            Deleted = 2//已被删除
        }
        public int id { get; set; }
        public string sender { get; set; }
        public string receiver { get; set; }
        public string title { get; set; }
        public string content { get; set; }
 
        public DateTime time { get; set; }
        public STATE state { get; set; }
 
        public Email() { }
 
        public Email(MySqlDataReader reader)
        {
            LoadFromReader(reader);
        }
 
        /// <summary>
        /// 从MySqlDataReader获取User实例
        /// </summary>
        /// <param name="reader">MySqlDataReader实例</param>
        public void LoadFromReader(MySqlDataReader reader)
        {
            id = reader[0].ToString().ToInt();
            sender = reader[1].ToString();
            receiver = reader[2].ToString();
            title = reader[3].ToString();
            content = reader[4].ToString();
            time = reader.GetDateTime(5);
            state = (STATE)reader[6].ToString().ToInt();
        }
 
        /// <summary>
        /// 获取概要，用于显示在TextBlock中
        /// </summary>
        /// <returns>string类型:标题+"\n"+概要</returns>
        public string GetDescription()
        {
            return (content.Length <= Value.UserForm.DESCRIPTION_MAX_LENGTH
                ? content
                : content.Substring(0, Value.UserForm.DESCRIPTION_MAX_LENGTH) + "...")
                + "\n";
        }
    }
}

MainPage.xaml

<Page x:Name="mainPage"
    x:Class="MailSystem_UWP.MainPage"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:local="using:MailSystem_UWP.Bean"
    xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
    xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
    mc:Ignorable="d" d:DesignWidth="744" d:DesignHeight="532">
    <Page.Resources>
        <DataTemplate x:Key="EMAIL" x:DataType="local:Email">
            <Grid Height="80" Margin="0,0,0,0">
                <TextBlock HorizontalAlignment="Left" Margin="10,10,0,0" Text="{x:Bind title}" TextWrapping="Wrap" VerticalAlignment="Top" FontWeight="Bold"/>
                <TextBlock Margin="0,10,10,0" Text="{x:Bind time}" TextWrapping="Wrap" VerticalAlignment="Top" HorizontalAlignment="Right" Width="auto" FontWeight="Normal"/>
                <TextBlock HorizontalAlignment="Left" Margin="10,34,0,10" Text="{x:Bind content}" TextWrapping="Wrap" Width="408"/>
            </Grid>
        </DataTemplate>
    </Page.Resources>
    <Grid>
        <ListView x:Name="listView" ItemTemplate="{StaticResource EMAIL}" HorizontalAlignment="Left" Width="325" Margin="0,55,0,0" Background="White" SelectionChanged="onSelectionChange" IsItemClickEnabled="True" ItemClick="onItemClick"/>
        <!--这里是其它控件-->
    </Grid>
</Page>

MainPage.xaml.cs

using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Runtime.InteropServices.WindowsRuntime;
using Windows.ApplicationModel.Core;
using Windows.Foundation;
using Windows.Foundation.Collections;
using Windows.UI.Core;
using Windows.UI.ViewManagement;
using Windows.UI.Xaml;
using Windows.UI.Xaml.Controls;
using Windows.UI.Xaml.Controls.Primitives;
using Windows.UI.Xaml.Data;
using Windows.UI.Xaml.Input;
using Windows.UI.Xaml.Media;
using Windows.UI.Xaml.Navigation;
using MailSystem_UWP.View;
using MailSystem_UWP.Bean;
using Windows.UI.Xaml.Media.Imaging;
using System.Windows.Input;
using System.Collections.ObjectModel;
 
// https://go.microsoft.com/fwlink/?LinkId=402352&clcid=0x804 上介绍了“空白页”项模板
 
namespace MailSystem_UWP
{
    public sealed partial class MainPage : Page
    {
        //已经删除了不相关的代码
 
        //数据绑定
        private static ObservableCollection<Email> data = new ObservableCollection<Email>();
        
 
        public MainPage()
        {
            this.InitializeComponent();
            listView.ItemsSource = data;
        }
 
        public void LoadEmail(List<Email> emails)
        {
            data.Clear();
            for(int i = 0; i < emails.Count; i++)
            {
                data.Add(emails[i]);
            }
        }
    }
}