如何将复选框项目拉伸到组合框的整个宽度

Question

我有一个带有复选框项的乘法组合框

<ComboBox  x:Name="cmb" IsEditable="True"  IsReadOnly="True" DropDownClosed="cmb_DropDownClosed">
    <ComboBox.ItemTemplate>
        <DataTemplate>
            <StackPanel Orientation="Horizontal">
            <CheckBox Content="{Binding NmColumn }"  HorizontalAlignment="Stretch"
                      IsChecked="{Binding Path=bChecked, Mode=TwoWay,UpdateSourceTrigger=PropertyChanged}" 
                      Tag="{Binding IdColumn}"
                      />
            </StackPanel>
        </DataTemplate>
    </ComboBox.ItemTemplate>
</ComboBox>

当我点击复选框时一切正常。但是，如果复选框宽度小于组合框的宽度，当我单击复选框右侧时，组合框将关闭。如何覆盖此行为？

Answer 1

在ComboBox.ItemContainerStyle中将HorizontalContentAlignment设置为Stretch:

<ComboBox  x:Name="cmb" IsEditable="True"  IsReadOnly="True" DropDownClosed="cmb_DropDownClosed">
        <ComboBox.ItemTemplate>
            <DataTemplate>
                <StackPanel Orientation="Vertical">
                    <CheckBox Content="{Binding NmColumn }"  HorizontalAlignment="Stretch"
                  IsChecked="{Binding Path=bChecked, Mode=TwoWay,UpdateSourceTrigger=PropertyChanged}" 
                  Tag="{Binding IdColumn}"
                  />
                </StackPanel>
            </DataTemplate> 
        </ComboBox.ItemTemplate>
        <ComboBox.ItemContainerStyle>
            <Style TargetType="{x:Type ComboBoxItem}">
                <Setter Property="HorizontalContentAlignment" Value="Stretch"/>
            </Style>
        </ComboBox.ItemContainerStyle>
    </ComboBox>

Answer 2

Ramin 的回答部分不错。您还必须从数据 template.It 中删除 <StackPanel Orientation="Horizontal"> 限制您的复选框在所有 ComboboxItem 宽度上扩展的他。

<ComboBox  x:Name="cmb" IsEditable="True"  IsReadOnly="True" DropDownClosed="cmb_DropDownClosed">
    <ComboBox.ItemTemplate>
        <DataTemplate>

                <CheckBox Content="{Binding NmColumn }"  HorizontalAlignment="Stretch"
              IsChecked="{Binding Path=bChecked, Mode=TwoWay,UpdateSourceTrigger=PropertyChanged}" 
              Tag="{Binding IdColumn}"
              />

        </DataTemplate> 
    </ComboBox.ItemTemplate>
    <ComboBox.ItemContainerStyle>
        <Style TargetType="{x:Type ComboBoxItem}">
            <Setter Property="HorizontalContentAlignment" Value="Stretch"/>
        </Style>
    </ComboBox.ItemContainerStyle>
</ComboBox>

Answer 3

所有答案都不适合我。 Trick 设置了什么

HorizontalContentAlignment="Stretch"

对于复选框：

<ComboBox x:Name="combobox"
    Background="White"
    Padding="2"
    Text="{Binding ElementName=DockPanelTemplateComboCheck, Path=ComboTextFilter}"
    IsEditable="True"
    IsReadOnly="True"
    HorizontalAlignment="Stretch"
    ItemsSource="{Binding ...}"
    IsDropDownOpen="{Binding Path=DropOpen, RelativeSource={RelativeSource Mode=FindAncestor, AncestorType={x:Type UserControl}}, UpdateSourceTrigger=PropertyChanged}">
    <ComboBox.ItemTemplate>
        <DataTemplate>
            <CheckBox IsChecked="{Binding IsChecked}" Content="{Binding Eintrag}" HorizontalContentAlignment="Stretch" Checked="CheckBox_Checked_Unchecked" Unchecked="CheckBox_Checked_Unchecked"/>
        </DataTemplate>
    </ComboBox.ItemTemplate>
    <ComboBox.ItemContainerStyle>
        <Style TargetType="{x:Type ComboBoxItem}">
            <Setter Property="HorizontalContentAlignment" Value="Stretch"/>
        </Style>
    </ComboBox.ItemContainerStyle>
</ComboBox>

代码隐藏：

    private string combotextfilter = "<No Selection>";

    public string ComboTextFilter
    {
        get { return combotextfilter; }
        set
        {
            if (value != null && value.IndexOf("ComboModel") != -1) return;
            combotextfilter = value;
            NotifyPropertyChanged(nameof(ComboTextFilter));
        }
    }

    private void CheckBox_Checked_Unchecked(object sender, RoutedEventArgs e)
    {
        switch (((ObservableCollection<ComboModel>)combobox.ItemsSource).Count(x => x.IsChecked))
        {
            case 0:
                ComboTextFilter = "<No Selection>";
                break;
            case 1:
                ComboTextFilter = ((ObservableCollection<ComboModel>)combobox.ItemsSource).Where(x => x.IsChecked).First().Eintrag;
                break;
            default:
                ComboTextFilter = ((ObservableCollection<ComboModel>)combobox.ItemsSource).Where(x => x.IsChecked).Select(x => x.Eintrag).Aggregate((i, j) => i + " | " + j);
                //ComboTextFilter = "<Multiple Selected>";
                break;
        }

        NotifyPropertyChanged(nameof(C_Foreground));
    }

    public bool DropOpen
    {
        get { return dropopen; }
        set { dropopen = value; NotifyPropertyChanged(nameof(ComboTextFilter)); }
    }
    private bool dropopen = false;

注意：此 ComboBox 还会根据所选元素更改 ComboBox 的文本。

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