Question

我在列表框中添加一些数据并使用Inotifypropertychanged来通知，在列表框中单击按钮数据后，它的代码非常简单但不起作用

我的xaml

> `Imports System.Collections.ObjectModel Imports System.ComponentModel`
> 
> 

    Public Class testdata
    >     Implements INotifyPropertyChanged

> 
>     Public Property listoffiles As List(Of String)
>         Get
>             Return _listoffiles
>         End Get
>         Set(value As List(Of String))
>             _listoffiles = value
>             onpropertchange("listoffiles")
>         End Set
>     End Property
> 
>     Public Property text As String
>         Get
>             Return _text
>         End Get
>         Set(value As String)
>             _text = value
>             onpropertchange("text")
>         End Set
>     End Property
> 
> 
>     Private _listoffiles As New List(Of String)
>     Private _text As String
> 
>     Public Sub New()
>         _listoffiles.Add("One")
>         _listoffiles.Add("One")
>         _listoffiles.Add("One")
>         
>     End Sub
> 
>     Protected Sub onpropertchange(name As String)
>         RaiseEvent PropertyChanged(Me, New PropertyChangedEventArgs(name))
>     End Sub
> 
>     Public Event PropertyChanged As PropertyChangedEventHandler Implements INotifyPropertyChanged.PropertyChanged End Class

My view.vb

> Class MainWindow
>    
> 
>     Private Property viewmodel As testdata = New testdata
>     Private Sub btntest_Click(sender As Object, e As RoutedEventArgs) Handles btntest.Click
>         viewmodel.listoffiles.Add("two")
>         viewmodel.listoffiles.Add("two")
>         viewmodel.listoffiles.Add("two")
>         viewmodel.listoffiles.Add("two")
>         viewmodel.listoffiles.Add("two")
>         
> 
>         Dim listoffiles As List(Of String) = viewmodel.listoffiles
>     End Sub End Cla

我的viewmodiel类

function ClearOld() {
    var ssActive = SpreadsheetApp.getActiveSpreadsheet();
        SpreadsheetApp.setActiveSheet(getSheetByName('Done'))

    var MyRange = ssActive.getRange("C:C");//selects C column
    var WeekAgo = new Date(date.getTime()-7*(24*3600*1000));
    for(i = 0; i < MyRange.length; i++) {
        if(MyRange[i].getTime()<WeekAgo){
            getActiveSheet().deleteRow(i);
        }
    }
}

SS

Answer 1

您需要将List更改为ObservableCollection。 ObservableCollection有一个名为NotifyCollectionChanged的活动。调用更新集合的Add()，Remove()等方法时会引发此事件。

因此，您需要对此进行以下代码更改

将listoffiles更改为公共财产
在datacontext

MainWindow

在listoffiles

viewmodel.listoffiles

MainWindow

下面是您在上面发布的代码的工作版本

Class MainWindow

Public Sub New()
    InitializeComponent()
    DataContext = Me
    listoffiles = viewmodel.listoffiles
End Sub
Private Property viewmodel As testdata = New testdata
Public Property listoffiles As New ObservableCollection(Of String)

Private Sub btntest_Click(sender As Object, e As RoutedEventArgs) Handles bnttest.Click
    viewmodel.listoffiles.Add("two")
    viewmodel.listoffiles.Add("two")
    viewmodel.listoffiles.Add("two")
    viewmodel.listoffiles.Add("two")
    viewmodel.listoffiles.Add("two")
End Sub
End Class



Public Class testdata
    Implements INotifyPropertyChanged


Public Property listoffiles As ObservableCollection(Of String)
    Get
        Return _listoffiles
    End Get
    Set(value As ObservableCollection(Of String))
        _listoffiles = value
    End Set
End Property

Public Property text As String
    Get
        Return _text
    End Get
    Set(value As String)
        _text = value

    End Set
End Property


Private _listoffiles As New ObservableCollection(Of String)
Private _text As String

Public Sub New()
    _listoffiles.Add("One")
    _listoffiles.Add("One")
    _listoffiles.Add("One")
End Sub

Protected Sub onpropertchange(name As String)
    RaiseEvent PropertyChanged(Me, New PropertyChangedEventArgs(name))
End Sub

Public Event PropertyChanged As PropertyChangedEventHandler Implements INotifyPropertyChanged.PropertyChanged
End Class

Answer 2

尝试更新您的绑定，如下所示......

ItemsSource="{Binding listoffiles, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}"

您的绑定可能在初始传递时正常工作，但它不会保持对该属性的更新。

INotifyPropertyChanged无效，WPF中的数据绑定

2 个答案: