如何将命令绑定到ListView的ItemSelectionChanged事件?

如何解决如何将命令绑定到ListView的ItemSelectionChanged事件?

| 是否可以将命令绑定到ListView的ItemSelectionChanged?怎么样?如果不可能,是否有另一种方法可以在列表视图的选择更改时调用命令?     

解决方法

是的-MVVM-light框架支持将命令数据绑定到路由事件。参见http://blog.galasoft.ch/archive/2009/11/05/mvvm-light-toolkit-v3-alpha-2-eventtocommand-behavior.aspx
<Rectangle Fill=\"White\"
           Stroke=\"Black\"
           Width=\"200\"
           Height=\"100\">
    <i:Interaction.Triggers>
        <i:EventTrigger EventName=\"MouseEnter\">
            <cmd:EventToCommand Command=\"{Binding TestCommand,Mode=OneWay}\"
               CommandParameter=\"{Binding Text,ElementName=MyTextBox,Mode=OneWay}\"
               MustToggleIsEnabledValue=\"True\" />
        </i:EventTrigger>
    </i:Interaction.Triggers>
</Rectangle>
    ,首先,我在我的项目中使用一条命令,其中selectedItems作为参数传递。这种方法的缺点是用户必须轻按命令按钮才能开始操作,但这在大多数情况下可以满足我的要求。 实现您想要的方式的方法是发布erash-使用诸如mvvm-light的EventToCommand行为。 另一种方法是创建附加行为以绑定到视图模型中的selecteditems。您必须将以下代码用于ListView或创建更通用的方法:)
<DataGrid AttachedProperties:DatagridService.SelectedItemsSource=\"{Binding SelectedItems,Mode=OneWay}\" />
ViewModel:
public ObservableCollection<object> SelectedItems//init collection just ONCE!
    {
        get
        {
            if (this.selectedItems == null)
            {
                this.selectedItems = new ObservableCollection<object>();
                this.selectedItems.CollectionChanged +=
                    new System.Collections.Specialized.NotifyCollectionChangedEventHandler(SelectedItemsCollectionChanged);
            }
            return this.selectedItems;
        }

    }

    private void SelectedItemsCollectionChanged(object sender,System.Collections.Specialized.NotifyCollectionChangedEventArgs e)
    {
        //this is called when ever the selecteditems changed
    }
附带行为:
public static class DatagridService
{
    #region SelectedItemSource

    #region Attached Property Declaration

    /// <summary>
    /// Identifies the ListBoxExtension.SelectedItemsSource attached property.
    /// </summary>
    public static readonly DependencyProperty SelectedItemsSourceProperty =
       DependencyProperty.RegisterAttached(
          \"SelectedItemsSource\",typeof(IList),typeof(DatagridService),new PropertyMetadata(
              null,new PropertyChangedCallback(OnSelectedItemsSourceChanged)));

    #endregion

    #region Attached Property Accessors

    /// <summary>
    /// Gets the IList that contains the values that should be selected.
    /// </summary>
    /// <param name=\"element\">The ListBox to check.</param>
    public static IList GetSelectedItemsSource(DependencyObject element)
    {
        if (element == null)
            throw new ArgumentNullException(\"element\");

        return (IList)element.GetValue(SelectedItemsSourceProperty);
    }

    /// <summary>
    /// Sets the IList that contains the values that should be selected.
    /// </summary>
    /// <param name=\"element\">The ListBox being set.</param>
    /// <param name=\"value\">The value of the property.</param>
    public static void SetSelectedItemsSource(DependencyObject element,IList value)
    {
        if (element == null)
            throw new ArgumentNullException(\"element\");

        element.SetValue(SelectedItemsSourceProperty,value);
    }

    #endregion

    #region IsResynchingProperty

    // Used to set a flag on the ListBox to avoid reentry of SelectionChanged due to
    // a full syncronisation pass
    private static readonly DependencyPropertyKey IsResynchingPropertyKey =
       DependencyProperty.RegisterAttachedReadOnly(
            \"IsResynching\",typeof(bool),new PropertyMetadata(false));

    #endregion

    #region Private Static Methods

    private static void OnSelectedItemsSourceChanged(DependencyObject d,DependencyPropertyChangedEventArgs e)
    {
        DataGrid grd = d as DataGrid;
        if (grd == null)
            throw new InvalidOperationException(\"The DataGridExtension.SelectedItemsSource attached \" +
               \"property can only be applied to DataGrid controls.\");

        grd.SelectionChanged -= new SelectionChangedEventHandler(OnDataGridSelectionChanged);

        if (e.NewValue != null)
        {
            ListenForChanges(grd);
        }

        BindingExpression bexp = grd.GetBindingExpression(SelectedItemsSourceProperty);
        if (bexp != null)
            bexp.UpdateSource();

    }

    private static void ListenForChanges(DataGrid grd)
    {
        // Wait until the element is initialised
        if (!grd.IsInitialized)
        {
            EventHandler callback = null;
            callback = delegate
            {
                grd.Initialized -= callback;
                ListenForChanges(grd);
            };
            grd.Initialized += callback;
            return;
        }

        grd.SelectionChanged += new SelectionChangedEventHandler(OnDataGridSelectionChanged);
        ResynchList(grd);
    }

    private static void OnDataGridSelectionChanged(object sender,SelectionChangedEventArgs e)
    {
        DataGrid grd = sender as DataGrid;
        if (grd != null)
        {
            bool isResynching = (bool)grd.GetValue(IsResynchingPropertyKey.DependencyProperty);
            if (isResynching)
                return;

            IList list = GetSelectedItemsSource(grd);

            if (list != null)
            {
                foreach (object obj in e.RemovedItems)
                {
                    if (list.Contains(obj))
                        list.Remove(obj);
                }
                foreach (object obj in e.AddedItems)
                {

                    if (!list.Contains(obj))
                        list.Add(obj);
                }
            }
        }
    }

    private static void ResynchList(DataGrid grd)
    {
        if (grd != null)
        {
            grd.SetValue(IsResynchingPropertyKey,true);
            IList list = GetSelectedItemsSource(grd);

            if (grd.SelectionMode == DataGridSelectionMode.Single)
            {
                grd.SelectedItem = null;
                if (list != null)
                {
                    if (list.Count > 1)
                    {
                        // There is more than one item selected,but the listbox is in Single selection mode
                        throw new InvalidOperationException(\"DataGrid is in Single selection mode,but was given more than one selected value.\");
                    }

                    if (list.Count == 1)
                        grd.SelectedItem = list[0];
                }
            }
            else
            {
                grd.SelectedItems.Clear();
                if (list != null)
                {
                    foreach (object obj in grd.Items)
                        if (list.Contains(obj))
                            grd.SelectedItems.Add(obj);
                }
            }

            grd.SetValue(IsResynchingPropertyKey,false);
        }
    }

    #endregion

    #endregion
}
    

版权声明:本文内容由互联网用户自发贡献,该文观点与技术仅代表作者本人。本站仅提供信息存储空间服务,不拥有所有权,不承担相关法律责任。如发现本站有涉嫌侵权/违法违规的内容, 请发送邮件至 dio@foxmail.com 举报,一经查实,本站将立刻删除。

相关推荐


依赖报错 idea导入项目后依赖报错,解决方案:https://blog.csdn.net/weixin_42420249/article/details/81191861 依赖版本报错:更换其他版本 无法下载依赖可参考:https://blog.csdn.net/weixin_42628809/a
错误1:代码生成器依赖和mybatis依赖冲突 启动项目时报错如下 2021-12-03 13:33:33.927 ERROR 7228 [ main] o.s.b.d.LoggingFailureAnalysisReporter : *************************** APPL
错误1:gradle项目控制台输出为乱码 # 解决方案:https://blog.csdn.net/weixin_43501566/article/details/112482302 # 在gradle-wrapper.properties 添加以下内容 org.gradle.jvmargs=-Df
错误还原:在查询的过程中,传入的workType为0时,该条件不起作用 &lt;select id=&quot;xxx&quot;&gt; SELECT di.id, di.name, di.work_type, di.updated... &lt;where&gt; &lt;if test=&qu
报错如下,gcc版本太低 ^ server.c:5346:31: 错误:‘struct redisServer’没有名为‘server_cpulist’的成员 redisSetCpuAffinity(server.server_cpulist); ^ server.c: 在函数‘hasActiveC
解决方案1 1、改项目中.idea/workspace.xml配置文件,增加dynamic.classpath参数 2、搜索PropertiesComponent,添加如下 &lt;property name=&quot;dynamic.classpath&quot; value=&quot;tru
删除根组件app.vue中的默认代码后报错:Module Error (from ./node_modules/eslint-loader/index.js): 解决方案:关闭ESlint代码检测,在项目根目录创建vue.config.js,在文件中添加 module.exports = { lin
查看spark默认的python版本 [root@master day27]# pyspark /home/software/spark-2.3.4-bin-hadoop2.7/conf/spark-env.sh: line 2: /usr/local/hadoop/bin/hadoop: No s
使用本地python环境可以成功执行 import pandas as pd import matplotlib.pyplot as plt # 设置字体 plt.rcParams[&#39;font.sans-serif&#39;] = [&#39;SimHei&#39;] # 能正确显示负号 p
错误1:Request method ‘DELETE‘ not supported 错误还原:controller层有一个接口,访问该接口时报错:Request method ‘DELETE‘ not supported 错误原因:没有接收到前端传入的参数,修改为如下 参考 错误2:cannot r
错误1:启动docker镜像时报错:Error response from daemon: driver failed programming external connectivity on endpoint quirky_allen 解决方法:重启docker -&gt; systemctl r
错误1:private field ‘xxx‘ is never assigned 按Altʾnter快捷键,选择第2项 参考:https://blog.csdn.net/shi_hong_fei_hei/article/details/88814070 错误2:启动时报错,不能找到主启动类 #
报错如下,通过源不能下载,最后警告pip需升级版本 Requirement already satisfied: pip in c:\users\ychen\appdata\local\programs\python\python310\lib\site-packages (22.0.4) Coll
错误1:maven打包报错 错误还原:使用maven打包项目时报错如下 [ERROR] Failed to execute goal org.apache.maven.plugins:maven-resources-plugin:3.2.0:resources (default-resources)
错误1:服务调用时报错 服务消费者模块assess通过openFeign调用服务提供者模块hires 如下为服务提供者模块hires的控制层接口 @RestController @RequestMapping(&quot;/hires&quot;) public class FeignControl
错误1:运行项目后报如下错误 解决方案 报错2:Failed to execute goal org.apache.maven.plugins:maven-compiler-plugin:3.8.1:compile (default-compile) on project sb 解决方案:在pom.
参考 错误原因 过滤器或拦截器在生效时,redisTemplate还没有注入 解决方案:在注入容器时就生效 @Component //项目运行时就注入Spring容器 public class RedisBean { @Resource private RedisTemplate&lt;String
使用vite构建项目报错 C:\Users\ychen\work&gt;npm init @vitejs/app @vitejs/create-app is deprecated, use npm init vite instead C:\Users\ychen\AppData\Local\npm-