How to keep ComboBox popup until I call close in t

Question

I want to keep the WPF ComboBox popup until the code I wrote let it close, how can I implement this?

Answer 1

Normally the property IsDropDown effects the popup,i edited the combobox template so the popup and the togglebutton who controls it- would be bined to other property -Tag

    <Style x:Key="ComboBoxStyle1" TargetType="{x:Type ComboBox}">
        <Setter Property="Template">
            <Setter.Value>
                <ControlTemplate TargetType="{x:Type ComboBox}">
                    <Grid x:Name="MainGrid" SnapsToDevicePixels="true">
                        <Grid.ColumnDefinitions>
                            <ColumnDefinition Width="*"/>
                            <ColumnDefinition MinWidth="{DynamicResource {x:Static SystemParameters.VerticalScrollBarWidthKey}}" Width="0"/>
                        </Grid.ColumnDefinitions>
                        <Popup x:Name="PART_Popup" StaysOpen="True" AllowsTransparency="true" Grid.ColumnSpan="2" IsOpen="{Binding Tag, RelativeSource={RelativeSource TemplatedParent}}" Margin="1" PopupAnimation="{DynamicResource {x:Static SystemParameters.ComboBoxPopupAnimationKey}}" Placement="Bottom">
                            <Microsoft_Windows_Themes:SystemDropShadowChrome x:Name="Shdw" Color="Transparent" MaxHeight="{TemplateBinding MaxDropDownHeight}" MinWidth="{Binding ActualWidth, ElementName=MainGrid}">
                                <Border x:Name="DropDownBorder" BorderBrush="{DynamicResource {x:Static SystemColors.WindowFrameBrushKey}}" BorderThickness="1" Background="{DynamicResource {x:Static SystemColors.WindowBrushKey}}">
                                    <ScrollViewer x:Name="DropDownScrollViewer">
                                        <Grid RenderOptions.ClearTypeHint="Enabled">
                                            <Canvas HorizontalAlignment="Left" Height="0" VerticalAlignment="Top" Width="0">
                                                <Rectangle x:Name="OpaqueRect" Fill="{Binding Background, ElementName=DropDownBorder}" Height="{Binding ActualHeight, ElementName=DropDownBorder}" Width="{Binding ActualWidth, ElementName=DropDownBorder}"/>
                                            </Canvas>
                                            <ItemsPresenter x:Name="ItemsPresenter" KeyboardNavigation.DirectionalNavigation="Contained" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}"/>
                                        </Grid>
                                    </ScrollViewer>
                                </Border>
                            </Microsoft_Windows_Themes:SystemDropShadowChrome>
                        </Popup>
                        <ToggleButton BorderBrush="{TemplateBinding BorderBrush}" Background="{TemplateBinding Background}" Grid.ColumnSpan="2" IsChecked="{Binding Tag, Mode=TwoWay, RelativeSource={RelativeSource TemplatedParent}}" Style="{StaticResource ComboBoxReadonlyToggleButton}"/>
                        <ContentPresenter ContentTemplate="{TemplateBinding SelectionBoxItemTemplate}" ContentTemplateSelector="{TemplateBinding ItemTemplateSelector}" Content="{TemplateBinding SelectionBoxItem}" ContentStringFormat="{TemplateBinding SelectionBoxItemStringFormat}" HorizontalAlignment="{TemplateBinding HorizontalContentAlignment}" IsHitTestVisible="false" Margin="{TemplateBinding Padding}" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}" VerticalAlignment="{TemplateBinding VerticalContentAlignment}"/>
                    </Grid>
                    <ControlTemplate.Triggers>
                        <Trigger Property="HasDropShadow" SourceName="PART_Popup" Value="true">
                            <Setter Property="Margin" TargetName="Shdw" Value="0,0,5,5"/>
                            <Setter Property="Color" TargetName="Shdw" Value="#71000000"/>
                        </Trigger>
                        <Trigger Property="HasItems" Value="false">
                            <Setter Property="Height" TargetName="DropDownBorder" Value="95"/>
                        </Trigger>
                        <Trigger Property="IsEnabled" Value="false">
                            <Setter Property="Foreground" Value="{DynamicResource {x:Static SystemColors.GrayTextBrushKey}}"/>
                            <Setter Property="Background" Value="#FFF4F4F4"/>
                        </Trigger>
                        <Trigger Property="IsGrouping" Value="true">
                            <Setter Property="ScrollViewer.CanContentScroll" Value="false"/>
                        </Trigger>
                        <Trigger Property="ScrollViewer.CanContentScroll" SourceName="DropDownScrollViewer" Value="false">
                            <Setter Property="Canvas.Top" TargetName="OpaqueRect" Value="{Binding VerticalOffset, ElementName=DropDownScrollViewer}"/>
                            <Setter Property="Canvas.Left" TargetName="OpaqueRect" Value="{Binding HorizontalOffset, ElementName=DropDownScrollViewer}"/>
                        </Trigger>
                    </ControlTemplate.Triggers>
                </ControlTemplate>
            </Setter.Value>
        </Setter>
    </Style>

then if you want to open\close the combobox you just need to set his Tag property to True\False :

<ComboBox  Style="{DynamicResource ComboBoxStyle1}" Tag="True"/>

Answer 2

ComboBox has a property IsDropDownOpen set it as True.And if you want Combobox stay open only while editing then you can set StaysOpenOnEdit equal to true

 <Grid>
    <Grid.RowDefinitions>
        <RowDefinition Height="Auto"/>
        <RowDefinition Height="*"/>
        <RowDefinition Height="Auto"/>
    </Grid.RowDefinitions>
    <ComboBox x:Name="cmb" IsDropDownOpen="True"/>
    <Button Click="Button_Click" Content="OK" Grid.Row="2"/>
</Grid>


    private void Button_Click(object sender, RoutedEventArgs e)
    {
        cmb.IsDropDownOpen = false;
    }

<ComboBox x:Name="cmb" StaysOpenOnEdit="True"/>

I hope this will help.