我在WPF应用程序中添加了一个对话框。这是Xaml：
<cs:CarSystemDialog x:Class="CarSystem.CustomControls.EditHotListDialog"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:cs="clr-namespace:CarSystem.CustomControls"
DataContext="{Binding Path=HotList, RelativeSource={RelativeSource Self}}"
Height="265"
Loaded="EditHotListDialog_Loaded"
MaxHeight="665"
MaxWidth="1200"
SizeToContent="WidthAndHeight"
cs:ThemeSelector.CurrentThemeDictionary="{Binding Path=TimeOfDayTheme, RelativeSource={RelativeSource Self}}"
Width="850"
WindowStartupLocation="CenterOwner" >
<cs:CarSystemDialog.Resources>
<cs:BooleanToVisibilityConverter x:Key="BoolToVisibility" True="Visible" False="Collapsed" />
<cs:CaseToVisibilityConverter x:Key="CaseToVisibilityConverter" />
</cs:CarSystemDialog.Resources>
<Grid Background="{DynamicResource ContentBackground}" FocusManager.IsFocusScope="True" Name="LayoutRoot">
<Grid.ColumnDefinitions>
<ColumnDefinition Width="Auto" />
<ColumnDefinition Width="*" />
<ColumnDefinition Width="Auto" />
<ColumnDefinition Width="*" />
</Grid.ColumnDefinitions>
<Grid.RowDefinitions>
<RowDefinition Height="Auto" />
<RowDefinition Height="Auto" />
<RowDefinition Height="Auto" />
<RowDefinition Height="Auto" />
</Grid.RowDefinitions>
<TextBlock FontSize="16"
FontWeight="Bold"
Foreground="{DynamicResource TextForeground}"
Grid.Column="0"
Grid.Row="0"
HorizontalAlignment="Right"
Margin="5"
Text="Source:"
VerticalAlignment="Center" />
<TextBox AcceptsTab="False"
AcceptsReturn="False"
BorderBrush="{DynamicResource ControlBorder}"
BorderThickness="2"
FontSize="16"
FontWeight="Bold"
Foreground="{DynamicResource UnfocusedForeground}"
Grid.Column="1"
Grid.Row="0"
Margin="5"
MaxLength="80"
MaxLines="1"
Name="HotListNameBox"
TabIndex="0"
Text="{Binding Path=Name, Mode=TwoWay}"
VerticalAlignment="Center" />
<TextBlock FontSize="16"
FontWeight="Bold"
Foreground="{DynamicResource TextForeground}"
Grid.Column="2"
HorizontalAlignment="Right"
Margin="5"
Text="List Type:"
VerticalAlignment="Center" />
<ComboBox BorderBrush="{DynamicResource PlateInfoBorder}"
DisplayMemberPath="Value"
FontSize="16"
FontWeight="Bold"
Grid.Column="3"
ItemsSource="{Binding Path=ListTypes, RelativeSource={RelativeSource AncestorType={x:Type cs:EditHotListDialog}}}"
Margin="5"
Name="ListTypePicker"
SelectedValue="{Binding Path=ListTypeId, Mode=TwoWay}"
SelectedValuePath="Key"
TabIndex="1" />
<TextBlock FontSize="16"
FontWeight="Bold"
Foreground="{DynamicResource TextForeground}"
Grid.Column="0"
Grid.Row="1"
HorizontalAlignment="Right"
Margin="5"
Text="Domain:"
VerticalAlignment="Center" />
<ComboBox BorderBrush="{DynamicResource PlateInfoBorder}"
DisplayMemberPath="Value"
FontSize="16"
FontWeight="Bold"
Grid.Column="1"
Grid.Row="1"
ItemsSource="{Binding Path=Domains, RelativeSource={RelativeSource AncestorType={x:Type cs:EditHotListDialog}}}"
Margin="5"
Name="DomainPicker"
SelectedValue="{Binding Path=DomainId, Mode=TwoWay}"
SelectedValuePath="Key"
TabIndex="1" />
<StackPanel Grid.Column="0"
Grid.ColumnSpan="4"
Grid.Row="2"
HorizontalAlignment="Center"
Orientation="Horizontal">
<Button Background="{DynamicResource ButtonBackground}"
Click="OkButton_Click"
Content="OK"
FontSize="18"
FontWeight="Bold"
Foreground="{DynamicResource ButtonForeground}"
Height="50"
IsDefault="True"
IsEnabled="{Binding Path=CanSave, RelativeSource={RelativeSource AncestorType={x:Type cs:EditHotListDialog}}}"
Margin="5"
Name="OkButton"
Width="100"/>
<Button Background="{DynamicResource ButtonBackground}"
Content="Cancel"
FontSize="18"
FontWeight="Bold"
Foreground="{DynamicResource ButtonForeground}"
Height="50"
IsCancel="True"
Margin="5"
Name="CancelButton"
Width="100" />
</StackPanel>
</Grid>
</cs:CarSystemDialog>
这是背后的代码：
public partial class EditHotListDialog : CarSystemDialog, INotifyPropertyChanged {
public static readonly DependencyProperty CanSaveProperty =
DependencyProperty.Register( "CanSave", typeof( bool ), typeof( EditHotListDialog ), new PropertyMetadata( false ) );
public static readonly DependencyProperty HotListProperty =
DependencyProperty.Register( "HotList", typeof( HotListViewModel ), typeof( EditHotListDialog ),
new PropertyMetadata( null, new PropertyChangedCallback( OnHotListChanged ) ) );
public bool CanSave {
get { return (bool) GetValue( CanSaveProperty ); }
set { SetValue( CanSaveProperty, value ); }
}
public ObservableCollection<ItemChoice<int?>> Domains { get; set; }
public HotListViewModel HotList {
get { return (HotListViewModel) GetValue( HotListProperty ); }
set { SetValue( HotListProperty, value ); }
}
public ObservableCollection<ItemChoice<int?>> ListTypes { get; set; }
public EditHotListDialog() {
InitializeComponent();
Domains = new ObservableCollection<ItemChoice<int?>>();
ListTypes = new ObservableCollection<ItemChoice<int?>>();
Domains .Add( new ItemChoice<int?> { Key = null, Value = "-- Pick a Domain --"} );
ListTypes.Add( new ItemChoice<int?> { Key = null, Value = "-- Pick a List Type --" } );
KeywordCache.KeywordCacheUpdated += KeywordCacheUpdated;
}
private void EditHotListDialog_Loaded( object sender, RoutedEventArgs e ) {
UpdateChoices();
DomainPicker.SelectedIndex = 0;
ListTypePicker.SelectedIndex = 0;
}
void HotList_PropertyChanged( object sender, PropertyChangedEventArgs e ) {
HotListViewModel hotList = sender as HotListViewModel;
CanSave = !( string.IsNullOrEmpty( hotList.Name ) || string.IsNullOrWhiteSpace( hotList.Name ) ) && hotList.ListTypeId > 0 && hotList.DomainId > 0;
}
private void OkButton_Click( object sender, RoutedEventArgs e ) {
if ( ValidateHotList() ) {
DialogResult = true;
Close();
}
e.Handled = true;
}
private void OnHotListChanged( HotListViewModel oldHotList, HotListViewModel newHotList ) {
if ( oldHotList != null ) {
oldHotList.PropertyChanged -= HotList_PropertyChanged;
}
if ( newHotList != null ) {
newHotList.PropertyChanged += HotList_PropertyChanged;
}
}
private static void OnHotListChanged( DependencyObject d, DependencyPropertyChangedEventArgs e ) {
EditHotListDialog dialog = d as EditHotListDialog;
dialog.OnHotListChanged( e.OldValue as HotListViewModel, e.NewValue as HotListViewModel );
}
private void UpdateChoices() {
. . .
}
private bool ValidateHotList() {
if ( string.IsNullOrEmpty( HotListNameBox.Text.Trim() ) ) {
CarSystemMessageBox.Show( "Please enter a name for the Hot List.", "Please Name the Hot List", MessageBoxButton.OK, MessageBoxImage.None );
return false;
}
if ( ListTypePicker.SelectedIndex <= 0 ) {
CarSystemMessageBox.Show( "Please select the List Type from the drop down that specifies what type of Hot List this is.", "Please Specify a List Type", MessageBoxButton.OK, MessageBoxImage.None );
return false;
}
if ( DomainPicker.SelectedIndex <= 0 ) {
CarSystemMessageBox.Show( "Please select the Domain from the drop down that this Hot List Entry belongs to.", "Please Specify a Domain", MessageBoxButton.OK, MessageBoxImage.None );
return false;
}
return true;
}
#region INotifyPropertyChanged Members
public event PropertyChangedEventHandler PropertyChanged;
protected void RaisePropertyChangedEvent( string propertyName ) {
if ( PropertyChanged != null ) {
PropertyChanged( this, new PropertyChangedEventArgs( propertyName ) );
}
}
#endregion
}
}
当我调试此代码时，我看到两个ObservableCollections填充了数据。这发生在UpdateChoices方法中。我已将UpdateChoices的调用放在构造函数中以及上面代码中的位置。
问题是，在填充了两个ObservableCollections之后，Items中没有ComboBoxes。当我将SelectedIndex属性设置为0时，不会选择任何内容。最后打开对话框时，在任一组合框中都没有选择任何内容。
我已经在我的应用程序UserControls上的MainWindow中使用了这个模式，但是这是我第一次在对话框中使用它。在哪里调用UpdateChoices方法并设置SelectedIndex的{{1}}属性的正确位置？
P.S。我没有包含UpdateChoices方法的细节，因为它与问题无关。
答案 0 :(得分：0)
您的DataContext设置为HotList，它与您尝试访问的属性处于同一级别。将DataContext更改为整个对话框，或将可观察集合移动到HotList对象中。
答案 1 :(得分：0)
我不知道绑定的问题是什么，但我摆脱了它，只是在对话框的ItemsSource事件处理程序中设置ComboBox控件的Loaded属性。现在一切都有效。
答案 2 :(得分：0)
查看MVVM模式。几乎不需要代码，你可以获得可测试的代码。