Question

我在数据网格中使用一个组合框，使用WPF和MVVM绑定到视图模型。虽然数据绑定项确实有数据，但我的组合框没有填充。我不确定我做错了什么。任何帮助将不胜感激。

我的第一个数据网格填充横截面数据。我的第二个数据网格填充了适当的区域数据。但是，组合框项目源和选定的横截面在第二个数据网格中不起作用。如果我在属性中为横截面和选定的横截面设置断点，我会到达断点。但是，数据未填充。

我更新了我的代码以反映建议的更改。下拉条目填充得很好，选定项目也是如此。但是，我注意到我在MainWindowViewModel和Zone viewmodel类中都有相同名称的属性。所以，我更新了Zone类，如下所示：

Imports GalaSoft.MvvmLight

Public Class Zone
   Inherits ViewModelBase

   Private _zoneNumber As Integer
   Private _selectedZoneCrossSection As CrossSection
   Private _length As Double

   Public Property ZoneNumber As Integer
      Get
         Return _zoneNumber
      End Get
      Set(value As Integer)
         _zoneNumber = value
         RaisePropertyChanged(Function() ZoneNumber)
      End Set
   End Property
   Public Property SelectedZoneCrossSection As CrossSection
      Get
         Return _selectedZoneCrossSection
      End Get
      Set(value As CrossSection)
         _selectedZoneCrossSection = value
         RaisePropertyChanged(Function() SelectedZoneCrossSection)
      End Set
   End Property
   Public Property Length As Double
      Get
         Return _length
      End Get
      Set(value As Double)
         _length = value
         RaisePropertyChanged(Function() Length)
      End Set
   End Property
End Class

然后，我按如下方式修改了MainWindow.xaml ComboBox组件，现在我按照预期工作......

       <DataGridComboBoxColumn Header="Cross Section"                                        
                                SelectedValueBinding="{Binding SelectedZoneCrossSection}"                        
                           DisplayMemberPath="RecordNumber">
          <DataGridComboBoxColumn.ElementStyle>
             <Style TargetType="ComboBox">
                <Setter Property="ItemsSource" Value="{Binding RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type Window}}, Path=DataContext.CrossSections}"/>
             </Style>
          </DataGridComboBoxColumn.ElementStyle>
          <DataGridComboBoxColumn.EditingElementStyle>
             <Style TargetType="ComboBox">
                <Setter Property="ItemsSource" Value="{Binding RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type Window}}, Path=DataContext.CrossSections}"/>
             </Style>
          </DataGridComboBoxColumn.EditingElementStyle>
       </DataGridComboBoxColumn>

My MainWindow.Xaml

<Window x:Class="MainWindow"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:local="clr-namespace:ComboBoxBinding"
    Title="MainWindow" Height="350" Width="800">
   <Window.DataContext>
      <local:MainWindowViewModel/>
   </Window.DataContext>

    <Grid>
      <StackPanel Orientation="Vertical">
         <DataGrid ItemsSource="{Binding CrossSections}"
                   SelectedItem="{Binding SelectedCrossSection}" 
                   AutoGenerateColumns="False"
                   >
            <DataGrid.Columns>
               <DataGridTextColumn Header="No." Binding="{Binding RecordNumber}"/>
               <DataGridTextColumn Header="Height" Binding="{Binding Height}"/>
               <DataGridTextColumn Header="Width" Binding="{Binding Width}"/>
               <DataGridTextColumn Header="Area" Binding="{Binding Area}"/>
            </DataGrid.Columns>
         </DataGrid>

         <Separator/>
         <DataGrid ItemsSource="{Binding Zones}" AutoGenerateColumns="True" 
                   SelectedItem="{Binding SelectedZone}">
            <DataGrid.Columns>
               <DataGridTextColumn Header="No." Binding="{Binding ZoneNumber}"/>
               <DataGridComboBoxColumn Header="Cross Section" 
                                       ItemsSource="{Binding CrossSections, Mode=OneWay, NotifyOnTargetUpdated=True, NotifyOnSourceUpdated=True}" 
                                       SelectedItemBinding="{Binding SelectedCrossSection}"
                                       DisplayMemberPath="RecordNumber"
                                       />
               <DataGridTextColumn Header="Length" Binding="{Binding Length}"/>
            </DataGrid.Columns>
         </DataGrid>
      </StackPanel>
    </Grid>
</Window>

我的MainWindowViewModel.vb

Imports System.Collections.ObjectModel
Imports GalaSoft.MvvmLight

Public Class MainWindowViewModel
   Inherits ViewModelBase

   Private _crossSections As ObservableCollection(Of CrossSection) = New ObservableCollection(Of CrossSection)()
   Private _selectedCrossSection As CrossSection
   Private _zones As ObservableCollection(Of Zone) = New ObservableCollection(Of Zone)
   Private _selectedZone As Zone

   Public Property CrossSections As ObservableCollection(Of CrossSection)
      Get
         Return _crossSections
      End Get
      Set(value As ObservableCollection(Of CrossSection))
         _crossSections = value
         RaisePropertyChanged(Function() CrossSections)
      End Set
   End Property
   Public Property SelectedCrossSection As CrossSection
      Get
         Return _selectedCrossSection
      End Get
      Set(value As CrossSection)
         _selectedCrossSection = value
         RaisePropertyChanged(Function() SelectedCrossSection)
      End Set
   End Property
   Public Property Zones As ObservableCollection(Of Zone)
      Get
         Return _zones
      End Get
      Set(value As ObservableCollection(Of Zone))
         _zones = value
         RaisePropertyChanged(Function() Zones)
      End Set
   End Property
   Public Property SelectedZone As Zone
      Get
         Return _selectedZone
      End Get
      Set(value As Zone)
         _selectedZone = value
         RaisePropertyChanged(Function() SelectedZone)
      End Set
   End Property

   Public Sub New()

      InitializeCrossSections()
      InitializeZones()

   End Sub

   Public Sub InitializeCrossSections()
      Dim oc As ObservableCollection(Of CrossSection) = New ObservableCollection(Of CrossSection)()
      Dim cs As CrossSection

      For i = 1 To 10
         cs = New CrossSection()
         cs.RecordNumber = i
         cs.Height = i
         cs.Width = i + 1
         cs.Area = cs.Height * cs.Width
         oc.Add(cs)
      Next
      CrossSections = New ObservableCollection(Of CrossSection)(oc)
      SelectedCrossSection = CrossSections(0)

   End Sub

   Public Sub InitializeZones()
      Dim oc As ObservableCollection(Of Zone) = New ObservableCollection(Of Zone)()
      Dim zn As Zone

      For i = 1 To 3
         zn = New Zone()
         zn.ZoneNumber = i
         zn.Length = 10 - i * 0.25
         zn.SelectedCrossSection = CrossSections(i)
         oc.Add(zn)
      Next
      Zones = New ObservableCollection(Of Zone)(oc)
      SelectedZone = Zones(0)
   End Sub
End Class

我的CrossSection类：

Imports GalaSoft.MvvmLight

Public Class CrossSection
   Inherits ViewModelBase

   Private _recordNumber As Integer
   Private _height As Double
   Private _width As Double
   Private _area As Double

   Public Property RecordNumber As Integer
      Get
         Return _recordNumber
      End Get
      Set(value As Integer)
         _recordNumber = value
         RaisePropertyChanged(Function() RecordNumber)
      End Set
   End Property
   Public Property Height As Double
      Get
         Return _height
      End Get
      Set(value As Double)
         _height = value
         RaisePropertyChanged(Function() Height)
      End Set
   End Property
   Public Property Width As Double
      Get
         Return _width
      End Get
      Set(value As Double)
         _width = value
         RaisePropertyChanged(Function() Width)
      End Set
   End Property
   Public Property Area As Double
      Get
         Return _area
      End Get
      Set(value As Double)
         _area = value
         RaisePropertyChanged(Function() Area)
      End Set
   End Property

End Class

我的区域类

Imports GalaSoft.MvvmLight

Public Class Zone
   Inherits ViewModelBase

   Private _zoneNumber As Integer
   Private _selectedCrossSection As CrossSection
   Private _length As Double

   Public Property ZoneNumber As Integer
      Get
         Return _zoneNumber
      End Get
      Set(value As Integer)
         _zoneNumber = value
         RaisePropertyChanged(Function() ZoneNumber)
      End Set
   End Property
   Public Property SelectedCrossSection As CrossSection
      Get
         Return _selectedCrossSection
      End Get
      Set(value As CrossSection)
         _selectedCrossSection = value
         RaisePropertyChanged(Function() SelectedCrossSection)
      End Set
   End Property
   Public Property Length As Double
      Get
         Return _length
      End Get
      Set(value As Double)
         _length = value
         RaisePropertyChanged(Function() Length)
      End Set
   End Property
End Class

Answer 1

我做了一些改动。请参阅以下代码。

<Grid>
    <StackPanel Orientation="Vertical">
        <DataGrid ItemsSource="{Binding CrossSections}"
               SelectedItem="{Binding SelectedCrossSection}" 
               AutoGenerateColumns="False"
               >
            <DataGrid.Columns>
                <DataGridTextColumn Header="No." Binding="{Binding RecordNumber}"/>
                <DataGridTextColumn Header="Height" Binding="{Binding Height}"/>
                <DataGridTextColumn Header="Width" Binding="{Binding Width}"/>
                <DataGridTextColumn Header="Area" Binding="{Binding Area}"/>
            </DataGrid.Columns>
        </DataGrid>

        <Separator/>
        <DataGrid ItemsSource="{Binding Zones}" AutoGenerateColumns="False" 
               SelectedItem="{Binding SelectedZone}">
            <DataGrid.Columns>
                <DataGridTextColumn Header="No." Binding="{Binding ZoneNumber}"/>
                <DataGridComboBoxColumn Header="Cross Section"                                        
                                        SelectedValueBinding="{Binding SelectedCrossSection}"                        
                                   DisplayMemberPath="RecordNumber">
                    <DataGridComboBoxColumn.ElementStyle>
                        <Style TargetType="ComboBox">
                            <Setter Property="ItemsSource" Value="{Binding RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type Window}}, Path=DataContext.CrossSections}"/>
                        </Style>
                    </DataGridComboBoxColumn.ElementStyle>
                    <DataGridComboBoxColumn.EditingElementStyle>
                        <Style TargetType="ComboBox">
                            <Setter Property="ItemsSource" Value="{Binding RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type Window}}, Path=DataContext.CrossSections}"/>
                        </Style>
                    </DataGridComboBoxColumn.EditingElementStyle>
                </DataGridComboBoxColumn>
                <DataGridTextColumn Header="Length" Binding="{Binding Length}"/>
            </DataGrid.Columns>
        </DataGrid>
    </StackPanel>
</Grid>

我的Combobox没有填充

1 个答案: