WPF UniformGrid动态内容

Question

我有一个统一的网格，我想动态显示内容/视图。它可以显示1、2、4或6个内容。我设置了统一网格行，col绑定和内容可见性绑定。对于视图/内容，这不起作用，但确实适用于矩形。这是为什么？我如何修改它以使用视图/内容。示例MainWindow.xaml代码.....

<StackPanel>
    <ComboBox HorizontalAlignment="Left" Width="50" SelectedIndex="{Binding SelectedIndex}">
        <ComboBoxItem IsSelected="True" Content="1" />
        <ComboBoxItem Content="2" />
        <ComboBoxItem Content="4" />
        <ComboBoxItem Content="6" />
    </ComboBox>

    <!-- NOT CORRECT, SHOWS 6 ITEMS ALWAYS -->
    <UniformGrid Rows="{Binding ScreenRows}" Columns="{Binding ScreenCols}">
        <local:ScreenView Grid.Row="0" Grid.Column="0" Visibility="{Binding VisibleScreen[0]}" />
        <local:ScreenView Grid.Row="0" Grid.Column="1" Visibility="{Binding VisibleScreen[1]}" />
        <local:ScreenView Grid.Row="0" Grid.Column="2" Visibility="{Binding VisibleScreen[2]}" />
        <local:ScreenView Grid.Row="1" Grid.Column="0" Visibility="{Binding VisibleScreen[3]}" />
        <local:ScreenView Grid.Row="1" Grid.Column="1" Visibility="{Binding VisibleScreen[4]}" />
        <local:ScreenView Grid.Row="1" Grid.Column="2" Visibility="{Binding VisibleScreen[5]}" />
    </UniformGrid>

    <!-- OK, SHOWS 1,2,4, or 6 RECT DEPENDING ON SelectedIndex -->
    <UniformGrid Rows="{Binding ScreenRows}" Columns="{Binding ScreenCols}">
        <Rectangle Width="20" Height="20" Grid.Row="0" Grid.Column="0" Fill="Red" Visibility="{Binding VisibleScreen[0]}" />
        <Rectangle Width="20" Height="20" Grid.Row="0" Grid.Column="1" Fill="Orange" Visibility="{Binding VisibleScreen[1]}" />
        <Rectangle Width="20" Height="20" Grid.Row="0" Grid.Column="2" Fill="Yellow" Visibility="{Binding VisibleScreen[2]}" />
        <Rectangle Width="20" Height="20" Grid.Row="1" Grid.Column="0" Fill="Green" Visibility="{Binding VisibleScreen[3]}" />
        <Rectangle Width="20" Height="20" Grid.Row="1" Grid.Column="1" Fill="Blue" Visibility="{Binding VisibleScreen[4]}" />
        <Rectangle Width="20" Height="20" Grid.Row="1" Grid.Column="2" Fill="Violet" Visibility="{Binding VisibleScreen[5]}" />
    </UniformGrid>

</StackPanel>

基本上，我有一个组合框。如果选择1，我的ViewModel将动态更改rows = 1，cols = 1，并显示第一个内容为Visible，其他的则折叠。它适用于矩形，但不适用于矩形。这是为什么？如何修复它以便使其适用于视图？

所有人都很好奇，这是MainWindowViewModel中的代码（原始MVVM）>

class MainWindowViewModel : BindableBase
{
    private const int SCREEN_MAX = 6;

    private int screenRows = 1;
    public int ScreenRows
    {
        get { return screenRows; }
        set { SetProperty(ref screenRows, value); }
    }

    private int screenCols = 1;
    public int ScreenCols
    {
        get { return screenCols; }
        set { SetProperty(ref screenCols, value); }
    }

    private Visibility[] visibleScreen = new Visibility[SCREEN_MAX];
    public Visibility[] VisibleScreen
    {
        get { return visibleScreen; }
        set { SetProperty(ref visibleScreen, value); }
    }

    private int selectedIndex;
    public int SelectedIndex
    {
        get { return selectedIndex; }
        set 
        { 
            SetProperty(ref selectedIndex, value);
            ChangeScreen(selectedIndex);                    
        }
    }

    private void ShowScreens(int num_screens)
    {
        // make all collapse
        for (int i = 0; i < SCREEN_MAX; i++)
            VisibleScreen[i] = Visibility.Collapsed;

        // show only X num screens
        for (int i = 0; i < num_screens; i++)
            VisibleScreen[i] = Visibility.Visible;

        RaisePropertyChanged("VisibleScreen");
    }

    public void ChangeScreen(int idx)
    {
        switch (idx)
        {
            case 0: ScreenRows = 1; ScreenCols = 1; ShowScreens(1); break;
            case 1: ScreenRows = 1; ScreenCols = 2; ShowScreens(2); break;
            case 2: ScreenRows = 2; ScreenCols = 2; ShowScreens(4); break;
            case 3: ScreenRows = 2; ScreenCols = 3; ShowScreens(6); break;
        }
    }
}
The ScreenView.xaml

<UserControl...>
    <!-- SOME HOW IT IS THIS DATACONTEXT CODE MESS UP THE UI -->
    <UserControl.DataContext>
        <local:ScreenViewModel x:Name="vm"/>
    </UserControl.DataContext>
    <StackPanel>
        <TextBlock>TEST</TextBlock>
    </StackPanel>
</UserControl>
样本输出

您可以从示例输出中看到，我的组合选择为1，因此它应该显示1 TEST，而显示1正方形是正确的。但是为什么要显示6个测试？如何显示1个TEST？

这是一个corect输出

谢谢！

我有一个统一的网格，我想动态显示内容/视图。它可以显示1、2、4或6个内容。我设置了统一网格行，col绑定和内容可见性绑定。这不是...

Answer 1

selectedIndex的初始值为0（int字段的默认值）。但是VisibleScreen数组的内容与selectedIndex不匹配-您需要在初始化期间调用ChangeScreen，例如像这样：