mvvm设计模式 listview绑定ICollectionView对象 如何获取多选数据

[mdh524]

在mvvm模式下页面与代码是分离的，在viewmodel 下可以通过
OrdersView.CurrentChanged += 事件
方式来获取单选，如果做到获取多选的值。

类似以下代码

public ObservableCollection<OrderViewModel> Orders
{
get;
private set;
}
public ICollectionView OrdersView
{
get
{
if( _ordersView == null )
_ordersView = CollectionViewSource.GetDefaultView( Orders );
return _ordersView;
}
}
private ICollectionView _ordersView;
public OrderViewModel CurrentOrder
{
get { return OrdersView.CurrentItem as OrderViewModel; }
set { OrdersView.MoveCurrentTo( value ); }
}

<ListView ItemsSource="{Binding Path=OrdersView}" IsSynchronizedWithCurrentItem="True">

[mdh524]

汗。。。居然没人。。

[沝林]

其实单选多选都可以不用ICollectionView的

单选，很简单，将SelectedItem与ViewModel的属性进行双向绑定就OK了

多选，由于ListView的SelectedItems不能进行绑定，需要将ListView的SelectionChanged事件转换成命令绑定到ViewModel，同时将SelectedItems传递到ViewModel层

示例：
首先添加程序集引用System.Windows.Interactivity.dll

xaml
添加命名空间引用

<UserControl ...
             xmlns:i="http://schemas.microsoft.com/expression/2010/interactivity" 
             />

      <ListView  ItemsSource="{Binding Source={StaticResource CustomerGroups}}" 
  		           x:Name="dataGrid1" >
        <ListView.GroupStyle>
            <StaticResourceExtension ResourceKey="CustomerGroupStyle" />
        </ListView.GroupStyle>
        <ListView.View>
        	<GridView>
        		<GridView.Columns>
        		  <GridViewColumn  DisplayMemberBinding="{Binding DisplayName,Mode=OneWay}" Header="Name" />
              <GridViewColumn  DisplayMemberBinding="{Binding Email,Mode=OneWay}" Header="E-Mail" />
              <GridViewColumn  DisplayMemberBinding="{Binding TotalSales,Mode=OneWay, ConverterCulture=zh-CN, StringFormat=c}" Header="Total Sales" />
        		</GridView.Columns>
          </GridView>
        </ListView.View>
        <i:Interaction.Triggers>
          <i:EventTrigger EventName="SelectionChanged">
            <i:InvokeCommandAction Command="{Binding SelectionChangeCommand}" CommandParameter="{Binding SelectedItems,ElementName=dataGrid1}"/>
          </i:EventTrigger>
        </i:Interaction.Triggers>
      </ListView>

viewmodel：

        public RelayCommand<IList> SelectionChangeCommand
        {
            get
            {
                return new RelayCommand<IList>
                    (
                        (selectedItems) =>
                        {
                            TotalSelectedSales = 0;

                            CustomerViewModel firstCustomer = null;

                            if (selectedItems.Count > 0)
                                firstCustomer = selectedItems[0] as CustomerViewModel;

                            // 将选中第一条CustomerViewModel传递到主页面
                            selectedCustomer = firstCustomer;

                            // 更新按钮的可执行状态
                            EditCustomerCommand.RaiseCanExecuteChanged();
                            DeleteCustomerCommand.RaiseCanExecuteChanged();

                            foreach (dynamic Item in selectedItems)
                                TotalSelectedSales += Item.TotalSales;

                            RaisePropertyChanged("TotalSelectedSales");
                        }
                    );
            }
        }

示例代码可以在这里下载，里面有mvvm中ListView多选的代码：

http://download.csdn.net/source/3287687

[namhyuk]

我盗取一段摘自网上的代码，你可以参考一下：

设有：CustomerViewModel, AllCustomerViewModel二个ViewModel,

<Style x:Key="CustomerItemStyle" TargetType="{x:Type ListViewItem}">
  <!-- 
  Bind the IsSelected property of a ListViewItem to the 
  IsSelected property of a CustomerViewModel object.
  -->
  <Setter Property="IsSelected" Value="{Binding Path=IsSelected, 
    Mode=TwoWay}" />
</Style>

// In AllCustomersViewModel.cs
public double TotalSelectedSales
{
    get
    {
        return this.AllCustomers.Sum(
            custVM => custVM.IsSelected ? custVM.TotalSales : 0.0);
    }
}

void OnCustomerViewModelPropertyChanged(object sender, 
    PropertyChangedEventArgs e)
{
    string IsSelected = "IsSelected";

    // When a customer is selected or unselected, we must let the
    // world know that the TotalSelectedSales property has changed,
    // so that it will be queried again for a new value.
    if (e.PropertyName == IsSelected)
        this.OnPropertyChanged("TotalSelectedSales");
}

这样提供一个思路……

当然你需要在AllCustomersViewModel构造函数里初始化如下代码：

foreach (CustomerViewModel cvm in all)
     cvm.PropertyChanged += this.OnCustomerViewModelPropertyChanged;

也就是说在AllCustomersViewModel里侦测CustomerViewModel的IsSelected（已经与ListViewItem.IsSelected进行双向绑定）的变化……