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我對Silverlight頗爲陌生，並且對通知機制有疑問。我的解決方案是一個MVVM應用程序堆疊是這樣的：GUI /視圖不會注意視圖模型中的更改。誰應該通知？
VIEW包含綁定到視圖模型集合的RadGridView，該數據是entitycollection。 GridView的SelectedItem被綁定到viewmodel中的相應屬性。
視圖模型 存放低於在GridView被綁定到的屬性和實現INotifyPropertyChanged。 •SelectList - 繼承ObservableCollection的實體集合。當SelectList被設置時，它運行一個通知呼叫。 •SelectedItem - 爲其自身屬性還實現INotifyPropertyChanged的實體。當SelectedItem設置時，它運行一個通知調用。
我的問題是，誰應該進行通知調用，以便GridView知道值已更改？偶爾，實體中的一個屬性直接在視圖模型中以編程方式設置。就目前而言，雖然屬性正確獲取新值，但GUI中沒有任何事情發生。
問候，柯樂
- 使用代碼------------------------- UPDATE
VIEW
<UserControl
xmlns:telerik="http://schemas.telerik.com/2008/xaml/presentation"
x:Class="X.Y.Z.MonthReport.MonthReportView"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
xmlns:toolkit="clr-namespace:System.Windows.Controls;assembly=System.Windows.Controls.Toolkit"
mc:Ignorable="d"
d:DesignHeight="300" d:DesignWidth="400">
<Grid x:Name="LayoutRoot">
<telerik:RadGridView x:Name="MonthReportGrid"
Grid.Row="1"
ItemsSource="{Binding SelectList}"
SelectedItem="{Binding SelectedItem, Mode=TwoWay}"
AutoGenerateColumns="False">
<telerik:RadGridView.Columns>
<!-- The other columns have been cut out of this example -->
<telerik:GridViewDataColumn DataMemberBinding="{Binding curDate, Mode=TwoWay, TargetNullValue=''}" DataFormatString="{} {0:d}" Header="Avläst datum" UniqueName="curDate" IsVisible="True" IsReadOnly="False">
<telerik:GridViewDataColumn.CellEditTemplate>
<DataTemplate>
<telerik:RadDateTimePicker SelectedValue="{Binding curDate, Mode=TwoWay, TargetNullValue=''}" InputMode="DatePicker" DateTimeWatermarkContent="ÅÅÅÅ-MM-DD" />
</DataTemplate>
</telerik:GridViewDataColumn.CellEditTemplate>
</telerik:GridViewDataColumn>
<telerik:GridViewDataColumn DataMemberBinding="{Binding curValue, Mode=TwoWay, TargetNullValue=''}" Header="Avläst värde" UniqueName="curValue" IsVisible="True" IsReadOnly="False" />
</telerik:RadGridView>
</Grid>
</UserControl>
VIEW .CS
using System;
using System.Collections.Generic;
using System.Windows.Data;
using System.Linq;
using System.Linq.Expressions;
using System.Windows.Controls;
using Telerik.Windows.Controls;
using Telerik.Windows.Controls.GridView;
namespace X.Y.Z.MonthReport
{
public partial class MonthReportView : UserControl, IMonthReportView
{
/// <summary>
/// ViewModel attached to the View
/// </summary>
public IMonthReportViewModel Model
{
get { return this.DataContext as IMonthReportViewModel; }
set { this.DataContext = value; }
}
public MonthReportView()
{
InitializeComponent();
this.MonthReportGrid.CellEditEnded += new EventHandler<GridViewCellEditEndedEventArgs>(MonthReportGrid_OnCellEditEnded);
}
public void MonthReportGrid_OnCellEditEnded(object sender, GridViewCellEditEndedEventArgs e)
{
if (e.Cell.Column.UniqueName == "curValue")
{
// ...
this.Model.SetAutomaticReadingDate();
}
if (e.Cell.Column.UniqueName == "curDate")
{
this.Model.UpdateAutomaticReadingDate();
}
}
}
}
視圖模型
using System;
using Microsoft.Practices.Prism.Events;
using Microsoft.Practices.Prism.Modularity;
using Microsoft.Practices.Unity;
using Microsoft.Practices.Prism.Commands;
namespace X.Y.Z.MonthReport
{
public class MonthReportViewModel : ViewModel<IMonthReportView>, IMonthReportViewModel
{
private readonly IEventAggregator eventAggregator;
private readonly IMonthReportService dataService;
private readonly IMonthReportController dataController;
private DateTime? _newReadingDate;
public DateTime? NewReadingDate
{
get { return _newReadingDate; }
set { _newReadingDate = value; }
}
//Holds the selected entity
private MonthReportEntity _selectedItem;
public MonthReportEntity SelectedItem
{
get { return _selectedItem; }
set
{
if (_selectedItem != value)
{
_selectedItem = value;
//The INotifyPropertyChanged implementation inherited from ViewModel-base.
Notify(() => this.SelectedItem);
}
}
}
//The entitycollection
private MonthReportEntityCollection _selectList;
public MonthReportEntityCollection SelectList
{
get { return _selectList; }
set
{
if (_selectList != value)
{
_selectList = value;
//The INotifyPropertyChanged implementation inherited from ViewModel-base.
Notify(() => this.SelectList);
}
}
}
public MonthReportViewModel(IMonthReportView view,
IEventAggregator eventAggregator, IMonthReportService dataService, IMonthReportController dataController)
{
this.InitializeCommands();
this.eventAggregator = eventAggregator;
this.dataController = dataController;
this.dataService = dataService;
this.View = view;
this.View.Model = this;
dataService.onGetMonthReportComplete += new EventHandler<MonthReportEventArgs>(OnGetMonthReportComplete);
dataService.onSaveMonthReportComplete += new EventHandler<MonthReportEventArgs>(OnSaveMonthReportComplete);
InitializeData();
}
public void InitializeCommands()
{
// ...
}
public void InitializeData()
{
GetMonthReport();
}
//This function is not working as I want it to.
//The gridview doesn't notice the new value.
//If a user edits the grid row, he should not need to
//add the date manually, Therefor I use this code snippet.
public void SetAutomaticReadingDate()
{
if ((NewReadingDate.HasValue) && (!SelectedItem.curDate.HasValue))
{
SelectedItem.curDate = NewReadingDate;
//The INotifyPropertyChanged implementation inherited from ViewModel-base.
Notify(() => this.SelectedItem.curDate);
}
}
public void GetMonthReport()
{
dataService.GetMonthReport();
}
public void SaveMonthReport()
{
dataService.SaveMonthReport(SelectList);
}
void OnGetMonthReportComplete(object sender, MonthReportEventArgs e)
{
// ...
}
void OnSaveMonthReportComplete(object sender, MonthReportEventArgs e)
{
// ...
}
#region ICleanable
public override void Clean()
{
base.Clean();
}
#endregion
}
}
你是否在後臺線程中操作viewmodel？如果不是，請張貼一些代碼 – thumbmunkeys