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从viewcell内的图像中从tapgesture访问列表数据

xamarin.forms xamarin listview c#

0

Phill · 技术社区 · 8 年前

我在一个 ViewCell TapGestureRecognizer 对于图像,现在当用户单击图像时,我想从数据中访问数据 可视单元格

2 回复 | 直到 8 年前

1

2

Pratius Dubey 8 年前

这是在ViewCell上传递数据的简单代码。

代码用户界面--

<ListView ItemsSource="{Binding ListItem}" x:Name="lst">
        <ListView.ItemTemplate>
            <DataTemplate>
                <ViewCell>
              <StackLayout>
               <Image Source="abcd" Aspect="AspectFit">
               <Image.GestureRecognizers>
               <TapGestureRecognizer Command="{Binding ClickCommand}" 
                      Source={x:Reference lst}}" 
                      CommandParameter="{Binding .}" />
                 </Image.GestureRecognizers>
                 </Image>
               </StackLayout>
                </ViewCell>
            </DataTemplate>
        </ListView.ItemTemplate>
    </ListView>

 Public Class MainViewModel
{
   Command clickCommand;
    public Command ClickCommand
    {
        get
        {
       return clickCommand ?? (menuTapCommand = new Command<Object>(GetImage));
        }
    }
Private Void GetImage(Object obj)
{
 //Todo
}}

2

0

TaylorD 8 年前

创建 DataTemplate 对于XF ViewCell BindingContext 在那张图像和细胞本身就是数据 可视单元格 图像识别器。它正确地执行 ICommand 在我的对象,其中包含所需的数据。你需要一个 i命令

<ListView ItemsSource="{Binding ListItem}">
    <ListView.ItemTemplate>
        <DataTemplate>
            <ViewCell>
                <StackLayout>
                    <Image Source="abcd">
                        <Image.GestureRecognizers>
                            <TapGestureRecognizer Command="{Binding ClickCommand}" />
                        </Image.GestureRecognizers>
                    </Image>
                </StackLayout>
            </ViewCell>
        </DataTemplate>
    </ListView.ItemTemplate>
</ListView>

数据 ListView的对象应具有 i命令

public class MyDataObject
{
    private Action<string> _openUrl;
    private string _url;

    public MyDataObject(string url, Action<string> openUrl)
    {
        _url = url;
        _openUrl = openUrl;

        ClickCommand = new Command(AccessOtherData);
    }

    public ICommand ClickCommand { get; }

    // Other data properties and such

    private void AccessOtherData()
    {
        // Call method to open _url
        _openUrl(_url);
    }
}

ObservableCollection 数据物体

public class ViewModel
{
    public event EventHandler<string> OpenUrl;

    // List filled with the MyDataObject
    public ObservableCollection<MyDataObject> Collection { get; set; }

    private void FillCollection()
    {
        // Create all MyDataObjects here
        // Each object will be created like this
        Collection.Add(new MyDataObject("insert url here", OpenUrlFromObject));
    }

    private void OpenUrlFromObject(string url)
    {
        OpenUrl?.Invoke(this, url); // Subscribe to this event in your Page and open
    }
}