xamarin表单:滑动以删除
xamarin表单:滑动以删除
提问于 2016-03-01 22:21:01
如何在我的笔记列表am中添加要删除的卷帘。我正在使用xamarin表单。我在xamarin表单样本中搜索过，但没有找到它。我还用menuItem等工具尝试了列表、视图、性能等选项，但我不知道如何在代码中进行调整。有没有人能帮我一下？我的代码如下：
public partial class MyPage
{
List<Note> notes;
string NotesFile {
get {
var documents = Environment.GetFolderPath (Environment.SpecialFolder.Personal);
return System.IO.Path.Combine (documents, "notes.json");
}
}
public MyPage()
{
BuildContent();
LoadNotes ();
ReloadListContents ();
AddNoteButton.Clicked += (sender, args) => {
var note = new Note("typ...");
notes.Add(note);
EditNote(note);
};
NoteListView.ItemTapped += (sender, row) =>
{
NoteListView.SelectedItem = null;
Note note = (Note)row.Item;
EditNote(note);
};
buttonDelete.Clicked += (sender, args) =>{
notes.RemoveAt(0);
DisplayAlert("Delete", "Row deleted", "OK");
};
}} MyPage.cs
{
public ListView NoteListView = new ListView ();
public Button AddNoteButton;
public Button buttonDelete;
private void BuildContent()
{
AddNoteButton = new Button
{
Text = "Add New Note",
TextColor = Color.White,
HorizontalOptions = LayoutOptions.Center,
VerticalOptions = LayoutOptions.Center
};
buttonDelete = new Button
{
Text = "Delete Note ",
TextColor = Color.White,
HorizontalOptions = LayoutOptions.Center,
VerticalOptions = LayoutOptions.Center
};
Content = new StackLayout
{
BackgroundColor = Color.Black,
Children = {
new Label {
Text = "Note Taker",
TextColor = Color.White
},
NoteListView,
AddNoteButton,
buttonDelete
}
};
}回答 1
Stack Overflow用户
发布于 2018-12-19 06:20:58
我正在用CS代码而不是XAML (我更喜欢)回答这个问题，如果有人想要Xaml响应，请在下面留言，我将在CS旁边写XAML。
因此，要完成在Xamarin.Forms中对ListView元素提出的要求，必须首先创建ViewCell，以便在ListView中的每个单元格中显示数据，并为其提供上下文操作。下面是一个示例：
public class CustomViewCell : ViewCell
{
public CustomViewCell()
{
//instantiate each element we want to use.
var image = new CircleCachedImage
{
Margin = new Thickness(20, 10, 0, 10),
WidthRequest = App.ScreenWidth * 0.15,
HeightRequest = App.ScreenWidth * 0.15,
Aspect = Aspect.AspectFill,
BorderColor = Color.FromHex(App.PrimaryColor),
BorderThickness = 2,
HorizontalOptions = LayoutOptions.Center
};
var nameLabel = new Label
{
Margin = new Thickness(20, 15, 0, 0),
FontFamily = "Lato",
FontAttributes = FontAttributes.Bold,
FontSize = 17
};
var locationLabel = new Label
{
Margin = new Thickness(20, 0, 0, 5),
FontFamily = "Lato",
FontSize = 13
};
//Create layout
var verticaLayout = new StackLayout();
var horizontalLayout = new StackLayout() { BackgroundColor = Color.White };
//set bindings
nameLabel.SetBinding(Label.TextProperty, new Binding("Name"));
locationLabel.SetBinding(Label.TextProperty, new Binding("Location"));
image.SetBinding(CircleCachedImage.SourceProperty, new Binding("Image"));
//Set properties for desired design
horizontalLayout.Orientation = StackOrientation.Horizontal;
horizontalLayout.HorizontalOptions = LayoutOptions.Fill;
image.HorizontalOptions = LayoutOptions.End;
//add views to the view hierarchy
horizontalLayout.Children.Add(image);
verticaLayout.Children.Add(nameLabel);
verticaLayout.Children.Add(locationLabel);
horizontalLayout.Children.Add(verticaLayout);
//HERE IS THE MOST IMPORTANT PART
var deleteAction = new MenuItem { Text = "Delete", IsDestructive = true }; // red background
deleteAction.Clicked += async (sender, e) => {
//Here do your deleting / calling to WebAPIs
//Now remove the item from the list. You can do this by sending an event using messaging center looks like:
//MessagingCenter.Send<TSender,string>(TSender sender, string message, string indexOfItemInListview)
};
// add to the ViewCell's ContextActions property
ContextActions.Add(deleteAction);
// add to parent view
View = horizontalLayout;
}
}现在，您必须对ListView执行以下操作：
listView = new ListView();
lstView.ItemTemplate = new DataTemplate(typeof(CustomViewCell));在您拥有ListView的同一个Content Page中，您还必须向MessagingCenter提供子电路，以侦听与上面在自定义视图单元格中设置的相同参数。如果您以前没有使用过MessagingCenter，请阅读提供的链接。在此方法内部，您必须从列表视图中删除该项，并将索引发送到此方法。
如果任何人需要任何进一步的解释，请在下面发表评论，我将编辑这篇文章。
页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持
原文链接：
https://stackoverflow.com/questions/35725383
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