C# 为什么更改DataGrid ComboBox值根本不会更新绑定属性？

我有一个DataGridComboxColumn，它应该显示整数或文本“Default”。当我添加行时，组合框从viewmodel的绑定属性中获得正确的值，但当我在用户界面中更改值时，不会调用属性集。我尝试了SelectedValueBinding和SelectedItemBinding。从不调用转换器的ConvertBack。我不知道应该叫它什么

<DataGrid Name="SelectionSetsGrid" CanUserAddRows="False" CanUserResizeColumns="True" CanUserSortColumns="True" 
              ItemsSource="{Binding SelectionSets}" AutoGenerateColumns="False"
              SelectedItem="{Binding SelectedSelectionSet}">
        <DataGridComboBoxColumn Header="{StaticResource XpStrTopologyWidth}" SelectedItemBinding="{Binding LineWidthIndex, UpdateSourceTrigger=PropertyChanged}">
            <DataGridComboBoxColumn.ElementStyle>
                <Style TargetType="ComboBox" BasedOn="{StaticResource Theme.ComboBox.Style}">
                    <Setter Property="ItemsSource" Value="{Binding RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type UserControl}}, Path=DataContext.LineWidths}"/>
                    <Setter Property="IsReadOnly" Value="True"/>
                    <Setter Property="ItemTemplate">
                        <Setter.Value>
                            <DataTemplate>
                                <WrapPanel>
                                    <TextBlock Text="{Binding Converter={StaticResource IntToIntTextOrDefaultConverter}}" VerticalAlignment="Center"/>
                                </WrapPanel>
                            </DataTemplate>
                        </Setter.Value>
                    </Setter>
                </Style>
            </DataGridComboBoxColumn.ElementStyle>
            <DataGridComboBoxColumn.EditingElementStyle>
                <Style TargetType="ComboBox" BasedOn="{StaticResource Theme.ComboBox.Style}">
                    <Setter Property="ItemsSource" Value="{Binding RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type UserControl}}, Path=DataContext.LineWidths}"/>
                    <Setter Property="ItemTemplate">
                        <Setter.Value>
                            <DataTemplate>
                                <WrapPanel>
                                    <TextBlock Text="{Binding Converter={StaticResource IntToIntTextOrDefaultConverter}}" VerticalAlignment="Center"/>
                                </WrapPanel>
                            </DataTemplate>
                        </Setter.Value>
                    </Setter>
                </Style>
            </DataGridComboBoxColumn.EditingElementStyle>
        </DataGridComboBoxColumn>                        
    </DataGrid.Columns>
</DataGrid>

有效的东西：

<DataGrid Name="SelectionSetsGrid" CanUserAddRows="False" CanUserResizeColumns="True" CanUserSortColumns="True" 
              ItemsSource="{Binding SelectionSets}" AutoGenerateColumns="False"
              SelectedItem="{Binding SelectedSelectionSet}">
        <DataGridComboBoxColumn Header="{StaticResource XpStrTopologyWidth}" SelectedItemBinding="{Binding LineWidthIndex, UpdateSourceTrigger=PropertyChanged}">
            <DataGridComboBoxColumn.ElementStyle>
                <Style TargetType="ComboBox" BasedOn="{StaticResource Theme.ComboBox.Style}">
                    <Setter Property="ItemsSource" Value="{Binding RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type UserControl}}, Path=DataContext.LineWidths}"/>
                    <Setter Property="IsReadOnly" Value="True"/>
                    <Setter Property="ItemTemplate">
                        <Setter.Value>
                            <DataTemplate>
                                <WrapPanel>
                                    <TextBlock Text="{Binding Converter={StaticResource IntToIntTextOrDefaultConverter}}" VerticalAlignment="Center"/>
                                </WrapPanel>
                            </DataTemplate>
                        </Setter.Value>
                    </Setter>
                </Style>
            </DataGridComboBoxColumn.ElementStyle>
            <DataGridComboBoxColumn.EditingElementStyle>
                <Style TargetType="ComboBox" BasedOn="{StaticResource Theme.ComboBox.Style}">
                    <Setter Property="ItemsSource" Value="{Binding RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type UserControl}}, Path=DataContext.LineWidths}"/>
                    <Setter Property="ItemTemplate">
                        <Setter.Value>
                            <DataTemplate>
                                <WrapPanel>
                                    <TextBlock Text="{Binding Converter={StaticResource IntToIntTextOrDefaultConverter}}" VerticalAlignment="Center"/>
                                </WrapPanel>
                            </DataTemplate>
                        </Setter.Value>
                    </Setter>
                </Style>
            </DataGridComboBoxColumn.EditingElementStyle>
        </DataGridComboBoxColumn>                        
    </DataGrid.Columns>
</DataGrid>

• DataGrid SelectedItem绑定
• 文本列双向绑定（此处略去以作简短说明）

这是我的密码：

<DataGrid Name="SelectionSetsGrid" CanUserAddRows="False" CanUserResizeColumns="True" CanUserSortColumns="True" 
              ItemsSource="{Binding SelectionSets}" AutoGenerateColumns="False"
              SelectedItem="{Binding SelectedSelectionSet}">
        <DataGridComboBoxColumn Header="{StaticResource XpStrTopologyWidth}" SelectedItemBinding="{Binding LineWidthIndex, UpdateSourceTrigger=PropertyChanged}">
            <DataGridComboBoxColumn.ElementStyle>
                <Style TargetType="ComboBox" BasedOn="{StaticResource Theme.ComboBox.Style}">
                    <Setter Property="ItemsSource" Value="{Binding RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type UserControl}}, Path=DataContext.LineWidths}"/>
                    <Setter Property="IsReadOnly" Value="True"/>
                    <Setter Property="ItemTemplate">
                        <Setter.Value>
                            <DataTemplate>
                                <WrapPanel>
                                    <TextBlock Text="{Binding Converter={StaticResource IntToIntTextOrDefaultConverter}}" VerticalAlignment="Center"/>
                                </WrapPanel>
                            </DataTemplate>
                        </Setter.Value>
                    </Setter>
                </Style>
            </DataGridComboBoxColumn.ElementStyle>
            <DataGridComboBoxColumn.EditingElementStyle>
                <Style TargetType="ComboBox" BasedOn="{StaticResource Theme.ComboBox.Style}">
                    <Setter Property="ItemsSource" Value="{Binding RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type UserControl}}, Path=DataContext.LineWidths}"/>
                    <Setter Property="ItemTemplate">
                        <Setter.Value>
                            <DataTemplate>
                                <WrapPanel>
                                    <TextBlock Text="{Binding Converter={StaticResource IntToIntTextOrDefaultConverter}}" VerticalAlignment="Center"/>
                                </WrapPanel>
                            </DataTemplate>
                        </Setter.Value>
                    </Setter>
                </Style>
            </DataGridComboBoxColumn.EditingElementStyle>
        </DataGridComboBoxColumn>                        
    </DataGrid.Columns>
</DataGrid>

XAML：

<DataGrid Name="SelectionSetsGrid" CanUserAddRows="False" CanUserResizeColumns="True" CanUserSortColumns="True" 
              ItemsSource="{Binding SelectionSets}" AutoGenerateColumns="False"
              SelectedItem="{Binding SelectedSelectionSet}">
        <DataGridComboBoxColumn Header="{StaticResource XpStrTopologyWidth}" SelectedItemBinding="{Binding LineWidthIndex, UpdateSourceTrigger=PropertyChanged}">
            <DataGridComboBoxColumn.ElementStyle>
                <Style TargetType="ComboBox" BasedOn="{StaticResource Theme.ComboBox.Style}">
                    <Setter Property="ItemsSource" Value="{Binding RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type UserControl}}, Path=DataContext.LineWidths}"/>
                    <Setter Property="IsReadOnly" Value="True"/>
                    <Setter Property="ItemTemplate">
                        <Setter.Value>
                            <DataTemplate>
                                <WrapPanel>
                                    <TextBlock Text="{Binding Converter={StaticResource IntToIntTextOrDefaultConverter}}" VerticalAlignment="Center"/>
                                </WrapPanel>
                            </DataTemplate>
                        </Setter.Value>
                    </Setter>
                </Style>
            </DataGridComboBoxColumn.ElementStyle>
            <DataGridComboBoxColumn.EditingElementStyle>
                <Style TargetType="ComboBox" BasedOn="{StaticResource Theme.ComboBox.Style}">
                    <Setter Property="ItemsSource" Value="{Binding RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type UserControl}}, Path=DataContext.LineWidths}"/>
                    <Setter Property="ItemTemplate">
                        <Setter.Value>
                            <DataTemplate>
                                <WrapPanel>
                                    <TextBlock Text="{Binding Converter={StaticResource IntToIntTextOrDefaultConverter}}" VerticalAlignment="Center"/>
                                </WrapPanel>
                            </DataTemplate>
                        </Setter.Value>
                    </Setter>
                </Style>
            </DataGridComboBoxColumn.EditingElementStyle>
        </DataGridComboBoxColumn>                        
    </DataGrid.Columns>
</DataGrid>

转换器：

public class IntToIntTextOrDefaultConverter : IValueConverter
{
    public object Convert(object value, Type targetType, object parameter,
        System.Globalization.CultureInfo culture)
    {
        if ((int)value == -1)
            return Fusion.App.Current.Resources["StrDefault"].ToString();

        return value.ToString();
    }

    public object ConvertBack(object value, Type targetType, object parameter,
        System.Globalization.CultureInfo culture)
    {
        return value.Equals(true) ? parameter : Binding.DoNothing;
    }
}

<DataGrid Name="SelectionSetsGrid" CanUserAddRows="False" CanUserResizeColumns="True" CanUserSortColumns="True" 
              ItemsSource="{Binding SelectionSets}" AutoGenerateColumns="False"
              SelectedItem="{Binding SelectedSelectionSet}">
        <DataGridComboBoxColumn Header="{StaticResource XpStrTopologyWidth}" SelectedItemBinding="{Binding LineWidthIndex, UpdateSourceTrigger=PropertyChanged}">
            <DataGridComboBoxColumn.ElementStyle>
                <Style TargetType="ComboBox" BasedOn="{StaticResource Theme.ComboBox.Style}">
                    <Setter Property="ItemsSource" Value="{Binding RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type UserControl}}, Path=DataContext.LineWidths}"/>
                    <Setter Property="IsReadOnly" Value="True"/>
                    <Setter Property="ItemTemplate">
                        <Setter.Value>
                            <DataTemplate>
                                <WrapPanel>
                                    <TextBlock Text="{Binding Converter={StaticResource IntToIntTextOrDefaultConverter}}" VerticalAlignment="Center"/>
                                </WrapPanel>
                            </DataTemplate>
                        </Setter.Value>
                    </Setter>
                </Style>
            </DataGridComboBoxColumn.ElementStyle>
            <DataGridComboBoxColumn.EditingElementStyle>
                <Style TargetType="ComboBox" BasedOn="{StaticResource Theme.ComboBox.Style}">
                    <Setter Property="ItemsSource" Value="{Binding RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type UserControl}}, Path=DataContext.LineWidths}"/>
                    <Setter Property="ItemTemplate">
                        <Setter.Value>
                            <DataTemplate>
                                <WrapPanel>
                                    <TextBlock Text="{Binding Converter={StaticResource IntToIntTextOrDefaultConverter}}" VerticalAlignment="Center"/>
                                </WrapPanel>
                            </DataTemplate>
                        </Setter.Value>
                    </Setter>
                </Style>
            </DataGridComboBoxColumn.EditingElementStyle>
        </DataGridComboBoxColumn>                        
    </DataGrid.Columns>
</DataGrid>

---

在某些情况下，例如在编辑文本列并按enter键或添加新行后，属性在更改combobox值后实际被更新（设置为调用）。因此，我只是将UpdateSourceTrigger=PropertyChanged添加到绑定中，并立即更新源属性（而不是在一些随机操作之后）。注意，从ComboBox更改焦点不足以更新源属性，所以我认为它从未更新过

<DataGrid Name="SelectionSetsGrid" CanUserAddRows="False" CanUserResizeColumns="True" CanUserSortColumns="True" 
              ItemsSource="{Binding SelectionSets}" AutoGenerateColumns="False"
              SelectedItem="{Binding SelectedSelectionSet}">
        <DataGridComboBoxColumn Header="{StaticResource XpStrTopologyWidth}" SelectedItemBinding="{Binding LineWidthIndex, UpdateSourceTrigger=PropertyChanged}">
            <DataGridComboBoxColumn.ElementStyle>
                <Style TargetType="ComboBox" BasedOn="{StaticResource Theme.ComboBox.Style}">
                    <Setter Property="ItemsSource" Value="{Binding RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type UserControl}}, Path=DataContext.LineWidths}"/>
                    <Setter Property="IsReadOnly" Value="True"/>
                    <Setter Property="ItemTemplate">
                        <Setter.Value>
                            <DataTemplate>
                                <WrapPanel>
                                    <TextBlock Text="{Binding Converter={StaticResource IntToIntTextOrDefaultConverter}}" VerticalAlignment="Center"/>
                                </WrapPanel>
                            </DataTemplate>
                        </Setter.Value>
                    </Setter>
                </Style>
            </DataGridComboBoxColumn.ElementStyle>
            <DataGridComboBoxColumn.EditingElementStyle>
                <Style TargetType="ComboBox" BasedOn="{StaticResource Theme.ComboBox.Style}">
                    <Setter Property="ItemsSource" Value="{Binding RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type UserControl}}, Path=DataContext.LineWidths}"/>
                    <Setter Property="ItemTemplate">
                        <Setter.Value>
                            <DataTemplate>
                                <WrapPanel>
                                    <TextBlock Text="{Binding Converter={StaticResource IntToIntTextOrDefaultConverter}}" VerticalAlignment="Center"/>
                                </WrapPanel>
                            </DataTemplate>
                        </Setter.Value>
                    </Setter>
                </Style>
            </DataGridComboBoxColumn.EditingElementStyle>
        </DataGridComboBoxColumn>                        
    </DataGrid.Columns>
</DataGrid>

幸运的是，绑定需要Mode=TwoWay？当然可以，但在DataGridComboBoxColumn绑定定义中，web中没有一个示例具有Mode=TwoWay。我试着用两种不同的方式来表达，但都没用。此外，文本列在无模式=双向的情况下工作。如果您知道如何正确地将其放入XAML，我会很高兴：）因为我以前也使用过复选框绑定，下面是我自己代码的一部分：

。更改了名称，但希望这有帮助。