[英]WPF Listbox selectionchanged MVVM
我的 WPF 應用程序中有一個列表框。 我知道如何使用 selectionchanged 事件。 但是我正在嘗試遵循 MVVM 設計。 但是我不確定該怎么做。
我已經為一個按鈕做了這個但是不確定我是否可以做同樣的事情?
<Button Grid.Column="0" Name="buttImport"
Content="Import File"
Command="{Binding CommandButtImport}"
Style="{StaticResource ButtonTemplate}"/>
public class ViewModel : INotifyPropertyChanged
{
// for the button that imports the orders file
public ICommand CommandButtImport { get; set; }
public ViewModel()
{
CommandButtImport = new MyCommands(
ExecuteCommandButtImport,
CanExecuteCommandButtImport);
}
private bool CanExecuteCommandButtImport(object parameter)
{
return true;
}
// import button
private void ExecuteCommandButtImport(object parameter)
{
// some code
}
}
編輯請忽略上面的代碼
我已經更改了我的代碼,因此已在我目前擁有的代碼下方重新發布。 我有一個奇怪的問題。 XAML - 主代碼包含我的數據網格的代碼。 App - XAML 下面的塊包含我的大部分應用程序的樣式,但這只是一個片段。
還
在 XAML 中我的數據網格下方添加了代碼行 - 用於測試目的的主代碼。
<ListBox ItemsSource="{Binding SelectedItem.DuplicateSecurities, ElementName=dataGridOrders}"
SelectedItem="{Binding SelectedItem.Security, ElementName=dataGridOrders}"/>
我的數據網格加載正常。 當我單擊一行時,該行會展開以顯示證券列表。 我遇到的問題是,當我單擊某個項目時,在此列表框中沒有任何反應。 但是,我出於測試目的添加到數據網格下方的列表框確實有效。 例如,我單擊其中一個項目,我的行被更新,我的行詳細信息中的列表框也被選中。 很奇怪為什么我的 rowdetail 中的列表框不起作用,但我的數據網格下面的列表框卻起作用。 有任何想法嗎?
XAML - 主碼
<StackPanel>
<!-- The data grid to display orders-->
<DataGrid DataContext="{Binding OrderBlock}"
x:Name="dataGridOrders"
ItemsSource="{Binding Orders}"
Style="{StaticResource DataGridTemplate}"
ColumnHeaderStyle="{StaticResource DG_ColumnHeader}"
RowHeaderStyle="{StaticResource DG_RowHeader}"
RowStyle="{StaticResource DG_Row}"
CellStyle="{StaticResource DG_Cell}"
RowDetailsTemplate="{StaticResource DG_RowDetail}"
AutoGenerateColumns="False"
HorizontalAlignment="Stretch"
VerticalAlignment="Stretch"
Background="Silver"
RowHeaderWidth="30"
Margin="25,5,20,15">
<DataGrid.Columns>
<DataGridComboBoxColumn Header="Action">
<DataGridComboBoxColumn.ElementStyle>
<Style TargetType="ComboBox">
<Setter Property="ItemsSource" Value="{Binding RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type DataGrid}}, Path=DataContext.StatusList}"/>
<Setter Property="IsReadOnly" Value="True"/>
<Setter Property="SelectedValue" Value="{Binding StatusGood}"/>
</Style>
</DataGridComboBoxColumn.ElementStyle>
<DataGridComboBoxColumn.EditingElementStyle>
<Style TargetType="ComboBox">
<Setter Property="ItemsSource" Value="{Binding RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type DataGrid}}, Path=DataContext.StatusList}"/>
<Setter Property="IsReadOnly" Value="True"/>
<Setter Property="SelectedValue" Value="{Binding StatusGood}"/>
</Style>
</DataGridComboBoxColumn.EditingElementStyle>
</DataGridComboBoxColumn>
<DataGridTextColumn Header="Fund" Binding="{Binding Account}" IsReadOnly="True"/>
<DataGridTextColumn Header="Security ID" Binding="{Binding Security.ID}" IsReadOnly="True"/>
<DataGridTextColumn Header="ThinkFolio Security ID" Binding="{Binding ThinkFolioSecurityID}" IsReadOnly="True"/>
<DataGridTextColumn Header="Security Name" Binding="{Binding Security.Name}" IsReadOnly="True"/>
<DataGridTextColumn Header="Buy/Sell" Binding="{Binding TransType}" IsReadOnly="True"/>
<DataGridTextColumn Header="Quantity" Binding="{Binding OrderQunatity, StringFormat=\{0:N0\}}" IsReadOnly="False"/>
<DataGridTextColumn Header="Currency" Binding="{Binding BuyCurrency}" IsReadOnly="False"/>
<DataGridTextColumn Header="Manager" Binding="{Binding FundManager}" IsReadOnly="True"/>
<DataGridTextColumn Header="Order Reason" Binding="{Binding OrderReason}" IsReadOnly="True"/>
<DataGridTextColumn Header="Reject Reason" Binding="{Binding RejectReason}" IsReadOnly="True" Width="*"/>
</DataGrid.Columns>
</DataGrid>
<ListBox ItemsSource="{Binding SelectedItem.DuplicateSecurities, ElementName=dataGridOrders}" SelectedItem="{Binding SelectedItem.Security, ElementName=dataGridOrders}"/>
</StackPanel>
應用程序 XAML
<!-- Row Detail Template for Data Grid -->
<DataTemplate x:Key="DG_RowDetail">
<Grid x:Name="RowDetailGrid"
Margin="5"
HorizontalAlignment="Left">
<Border HorizontalAlignment="Left"
VerticalAlignment="Top"
Width="500"
Height="80"
CornerRadius="5">
<Border.Background>
<LinearGradientBrush StartPoint="0,0" EndPoint="0,1">
<GradientStop Offset="0" Color="Transparent"/>
<GradientStop Offset="1" Color="Transparent"/>
</LinearGradientBrush>
</Border.Background>
<Grid>
<Grid.RowDefinitions>
<RowDefinition Height="*"/>
<RowDefinition Height="2.5*"/>
</Grid.RowDefinitions>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="*"/>
</Grid.ColumnDefinitions>
<TextBlock Grid.Row="0"
Grid.ColumnSpan="3"
Margin="5,0,0,5"
HorizontalAlignment="Left"
FontSize="12"
FontWeight="Bold"
Foreground="Black"
Text="Select Security Identifier">
</TextBlock>
<ListBox Grid.Row="1" Grid.ColumnSpan="3" Name="lbIdentifier" ItemsSource="{Binding DuplicateSecurities}" SelectedItem="{Binding Security}"
SelectionMode="Single" HorizontalContentAlignment="Stretch">
<ListBox.ItemTemplate>
<DataTemplate>
<Grid Margin="0,2">
<Grid.ColumnDefinitions>
<ColumnDefinition/>
<ColumnDefinition Width="*"/>
</Grid.ColumnDefinitions>
<TextBlock Grid.Column="0" Text="{Binding Path=ID}" FontSize="10" HorizontalAlignment="Left" Margin="5,0,0,0"/>
<TextBlock Grid.Column="1" Text="{Binding Path=Name}" FontSize="10" HorizontalAlignment="Left" Margin="5,0,0,0"/>
</Grid>
</DataTemplate>
</ListBox.ItemTemplate>
</ListBox>
</Grid>
</Border>
</Grid>
</DataTemplate>
視圖模型
public class ViewModel : INotifyPropertyChanged
{
public ICommand CommandButtImport { get; set; } // for the button that imports the orders file
public ICommand CommandButtSend { get; set; } // the button where the user sends the orders in our data grid to thinkFolio
public ICommand CommandButtExit { get; set; } // exit application
private QoEMain _QoEManager; // manages the Model
public QoEMain QoEManager { get { return this._QoEManager; } set { _QoEManager = value; } }
private OrderBlocks _orderBlock; // order block - contains all the order information
public OrderBlocks OrderBlock
{
get
{
return this._orderBlock;
}
set
{
this._orderBlock = value;
OnPropertyChanged("OrderBlock");
}
}
}
包含其他類的 OrderBlocks Class
public class OrderBlocks : INotifyPropertyChanged
{
private List<Order> _orders;
[XmlElement("tF_Transactions")]
public List<Order> Orders { get { return _orders; } set { _orders = value; OnPropertyChanged("Orders"); } }
}
訂單Class
public class Order : INotifyPropertyChanged
{
Security security;
public Security Security
{
get { return security; }
set { security = value; OnPropertyChanged("Security"); }
}
List<Security> duplicateSecurities;
public List<Security> DuplicateSecurities
{
get { return duplicateSecurities; }
set { duplicateSecurities = value; OnPropertyChanged("DuplicateSecurities"); }
}
保安 Class
public class Security : INotifyPropertyChanged
{
private string _id;
public string ID
{
get
{
return _id;
}
set
{
_id = value;
OnPropertyChanged("ID");
}
}
private string _name;
public string Name
{
get
{
return _name;
}
set
{
_name = value;
OnPropertyChanged("Name");
}
}
public Security() { }
public Security(string newID, string newName)
{
ID = newID;
Name = newName;
}
編輯 - 我的代碼現在可以使用了,請參閱下面對我有用的代碼片段
<DataGrid Grid.Row="1" Grid.Column="0"
ItemsSource="{Binding SelectedItem.DuplicateSecurities, ElementName=dataGridOrders}"
SelectedItem="{Binding SelectedItem.Security, ElementName=dataGridOrders}">
將ListBox SelectionChanged
事件綁定到ViewModel中的命令示例
<ListBox x:Name="myListBox" ItemsSource="{Binding SomeCollection}">
<ie:Interaction.Triggers>
<ie:EventTrigger EventName="SelectionChanged">
<ie:InvokeCommandAction Command="{Binding SelectedItemChangedCommand}" CommandParameter="{Binding ElementName=myListBox, Path=SelectedItem}"/>
</ie:EventTrigger>
</ie:Interaction.Triggers>
</ListBox >
在您的ViewModel
:
public class myViewModel
{
public myViewModel()
{
SelectedItemChangedCommand = new DelegateCommand<object>((selectedItem) =>
{
// Logic goes here
});
}
public List<SomeData> SomeCollection { get; set; }
public DelegateCommand<object> SelectedItemChangedCommand { get; set; }
}
此特定示例使用Prism MVVM Framework,但您可以將相同的想法應用於您正在使用的任何其他MVVM框架。
希望這可以幫助
將SelectionChanged
與MVVM一起使用非常簡單:
一種方法可以是綁定到ListBox
的SelectedIndex
屬性,並在VM中的屬性設置器中,相應地執行操作,因為只要屬性更改它就會被觸發。
示例: 這里
在此示例中,只要所選索引發生更改,該項的值就會增加1。
主要是:
public int SelectedIndex {
get {
return _selectedIndex;
}
set {
if (_selectedIndex == value) {
return;
}
// At this point _selectedIndex is the old selected item's index
_selectedIndex = value;
// At this point _selectedIndex is the new selected item's index
RaisePropertyChanged(() => SelectedIndex);
}
}
xaml只會是:
<ListBox ItemsSource="{Binding Items}" SelectedIndex="{Binding SelectedIndex}" />
Items
是我們綁定的項目的集合。
System.Windows.Interactivity.WPF package 已棄用。
安裝Microsoft.Xaml.Behaviors.Wpf package
<ListBox ItemsSource="{Binding ListItems}" DisplayMemberPath="Name" SelectedItem="{Binding SelectedItem}">
<Behaviors:Interaction.Triggers>
<Behaviors:EventTrigger EventName="SelectionChanged">
<Behaviors:InvokeCommandAction Command="{Binding ItemChangedCommand}" />
</Behaviors:EventTrigger>
</Behaviors:Interaction.Triggers>
</ListBox>
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