WPF Change Window Layout Based on Combo Box Selection Using MVVM

问题

I need to change the layout of my window based on what the user selects in a combo box. I've made a stab at what one way might be but feel like it is clunky and hacked together. Im certain their must be a cleaner MVVM solution.

My thoughts where to have multiple dock panels in my GroupBox Whose visibility is set to collapse. When the selection is made, the appropriate dockpanel will be set to visible. I attempted to find a way to do this inside the view model with no success. I also couldn't help but think my attempts are violating MVVM.

XAML

<GroupBox Header="Options">
    <Grid>
        <DockPanel LastChildFill="False" x:Name="syncWellHeadersDockPanel" Visibility="Collapsed">
            <Button DockPanel.Dock="Right" Content="Test"></Button>
        </DockPanel>
        <DockPanel LastChildFill="False" x:Name="SyncDirectionalSurveyDockPanel" Visibility="Collapsed">
            <Button DockPanel.Dock="Left" Content="Test02"></Button>
        </DockPanel>

    </Grid>
</GroupBox>

ViewModel - Property for Selected Item for ComboBox

private StoredActionsModel _selectedStoredAction = DefaultStoredAction.ToList<StoredActionsModel>()[0];
        public StoredActionsModel SelectedStoredAction
        {
            get { return _selectedStoredAction; }
            set
            {
                if (value != _selectedStoredAction)
                {
                    //  Unset Selected on old value, if there was one
                    if (_selectedStoredAction != null)
                    {
                        _selectedStoredAction.Selected = false;
                    }
                    _selectedStoredAction = value;
                    //  Set Selected on new value, if there is one
                    if (_selectedStoredAction != null)
                    {
                        _selectedStoredAction.Selected = true;
                    }
                    OnPropertyChanged("SelectedStoredAction");

                    if (_selectedStoredAction.StoredActionID == 4)
                    {
                        //X:SyncWellHeaderDockPanel.visibility = true?????
                    }
                }
            }
        }

回答1:

Here's a pure-XAML way to do exactly what you're asking how to do. It's a bit verbose.

Notice that we no longer set Visibility in attributes on the DockPanels. If we still did that, the values set in the Style trigger would be overridden by the attributes. That's the way dependency properties work.

<GroupBox Header="Options">
    <Grid>
        <DockPanel LastChildFill="False" x:Name="syncWellHeadersDockPanel" >
            <Button DockPanel.Dock="Right" Content="Test"></Button>
            <DockPanel.Style>
                <Style TargetType="DockPanel" >
                    <Setter Property="Visibility" Value="Collapsed" />
                    <Style.Triggers>
                        <DataTrigger 
                            Binding="{Binding SelectedStoredAction.StoredActionID}" 
                            Value="1"
                            >
                            <Setter Property="Visibility" Value="Visible" />
                        </DataTrigger>
                    </Style.Triggers>
                </Style>
            </DockPanel.Style>
        </DockPanel>
        <DockPanel LastChildFill="False" x:Name="SyncDirectionalSurveyDockPanel">
            <Button DockPanel.Dock="Left" Content="Test02"></Button>
            <DockPanel.Style>
                <Style TargetType="DockPanel" >
                    <Setter Property="Visibility" Value="Collapsed" />
                    <Style.Triggers>
                        <DataTrigger 
                            Binding="{Binding SelectedStoredAction.StoredActionID}" 
                            Value="2"
                            >
                            <Setter Property="Visibility" Value="Visible" />
                        </DataTrigger>
                    </Style.Triggers>
                </Style>
            </DockPanel.Style>
        </DockPanel>
    </Grid>
</GroupBox>

Another way to do this would be to pass SelectedStoredAction.StoredActionID to a DataTemplateSelector, but that involves writing C# code that knows what your XAML resource keys are, and I'm not a fan.

来源：https://stackoverflow.com/questions/41877466/wpf-change-window-layout-based-on-combo-box-selection-using-mvvm

标签

wpf

xaml

mvvm

combobox