C# 布局问题试图使ListView显示固定数量的项目_C#_Xaml_Listview_Layout_Uwp

C# 布局问题试图使ListView显示固定数量的项目

c# xaml listview layout uwp

C# 布局问题试图使ListView显示固定数量的项目,c#,xaml,listview,layout,uwp,C#,Xaml,Listview,Layout,Uwp,在UWP项目中，我有一个列表视图，它绑定到个人对象的可观察集合。我使用DataTemplate在列表视图中显示Person对象。集合（人员）最多只能包含由\u maxPeopleCount设置的特定数量的人员我希望列表视图能够：根本不滚动显示由\u maxPeopleCount定义的所有Person对象完整显示每个人对象，而不是部分显示。也就是说，显示每个项目，以便ListViewItem.Height=（ItemsPanel中的可用高度）/\u maxPeopleCount 当要开始的

在UWP项目中，我有一个

列表视图

，它绑定到

个人

对象的

可观察集合

。我使用

DataTemplate

在

列表视图中显示Person
对象。集合（人员）最多只能包含由\u maxPeopleCount
设置的特定数量的人员
我希望列表视图
能够：
根本不滚动
显示由\u maxPeopleCount
定义的所有Person
对象
完整显示每个人
对象，而不是部分显示。也就是说，显示每个项目，以便ListViewItem.Height=（ItemsPanel中的可用高度）/\u maxPeopleCount
当要开始的项目少于\u maxPeopleCount
时，仍显示添加的项目，其高度如（3）中所定义
将每个人的名字和姓氏显示得尽可能大
目前，我无法让我的项目做到这一点
下面是显示问题的示例代码。只需按下按钮7次以上，因为这是代码中的\u maxPeopleCount
。你会看到7个人没有被展示。为糟糕的用户界面道歉。它的目的是用最小的XAML来显示问题，但与我的实际项目类似
代码隐藏：
public sealed partial class MainPage : Page
{
    ObservableCollection<Person> _people = new ObservableCollection<Person>();
    int _personCount = 0;
    int _maxPeopleCount = 7;
    public MainPage()
    {
        this.InitializeComponent();
        this.DataContext = _people;

    }

    private void btnAddPerson_Click(object sender, RoutedEventArgs e)
    {
        if (_people.Count == _maxPeopleCount)
        {
            _people.RemoveAt(_people.Count - 1);
        }
        _personCount += 1;
        _people.Insert(0, new Person($"FirstName {_personCount}", $"LastName {_personCount}"));
    }

根本不滚动
为此，您已经通过ScrollViewer.VerticalScrollMode=“Disabled”ScrollViewer.VerticalScrollBarVisibility=“Hidden”
完成了
显示由_maxPeopleCount定义的所有Person对象
实际上，您已经将\u maxPeopleCount
个人记录绑定到列表视图
，但受窗口大小的限制，您无法看到所有记录。看不见的记录确实存在。如果通过手动拖动来拉伸应用程序窗口的大小，使其高度更大，则会看到剩余的记录。如果要使所有记录始终可见，可能需要自己计算ListViewItem
高度
完全显示每个人的对象，而不是部分显示。也就是说，显示每个项目，以便ListViewItem.Height=（ItemsPanel中的可用高度）/\u maxPeopleCount
在您的场景中，ListViewItem
的高度是自动计算的，因为您没有为其设置固定高度。正如您在这里展示的公式，我们可以在代码隐藏中按类动态绑定ListViewItem
的高度。请注意，窗口大小的更改将影响列表视图的实际大小，因此当应用程序更改窗口大小时，我们还需要调整列表视图项的大小。当ListViewItem
的高度设置为小于44
时，它不会生效，因为默认的MinHeight
为44
，需要重置。有关实现此要求的更多设置，请参考下面的演示
当要开始的maxPeopleCount项目少于_时，仍会显示添加的项目，其高度如（3）中所定义
计算后，所有的ListViewItem
将具有相同的高度
将每个人的名字和姓氏显示得尽可能大
为此，您有
来拉伸水平内容，也请通过
拉伸垂直内容。需要将ListviewItem
的padding
设置为0

更新代码如下，现在可以满足您的所有上述要求
XAML


代码隐藏
public sealed partial class MainPage : Page
{
    ObservableCollection<Person> _people = new ObservableCollection<Person>();
    int _personCount = 0;
    int _maxPeopleCount = 7;
    public MainPage()
    {
        this.InitializeComponent();
        this.DataContext = _people;
        Window.Current.SizeChanged += Current_SizeChanged;
    } 
    public void resize()
    { 
        var listpersonheight = listperson.ActualHeight; 
        IEnumerable<ListViewItem> items = FindVisualChildren<ListViewItem>(listperson);
        for (int i = 0; i < items.Count(); i++)
        {
            foreach (ListViewItem item in items)
            {
                item.Height = (listpersonheight - 10) / _maxPeopleCount;// BorderThickness size need to be minus.
                item.Width = listperson.ActualWidth - 10; //Width also need resize.
            }
        }
    }
    private void Current_SizeChanged(object sender, Windows.UI.Core.WindowSizeChangedEventArgs e)
    {
        resize();
    }
    private void grdPerson_Loaded(object sender, RoutedEventArgs e)
    {
        resize();
    }
    private void btnAddPerson_Click(object sender, RoutedEventArgs e)
    { 
        if (_people.Count == _maxPeopleCount)
        {
            _people.RemoveAt(_people.Count - 1);
        }
        _personCount += 1; 
        _people.Insert(0, new Person($"FirstName {_personCount}", $"LastName {_personCount}")); 
    }

    private static IEnumerable<T> FindVisualChildren<T>(DependencyObject depObj) where T : DependencyObject
    {
        if (depObj != null)
        {
            for (int i = 0; i < VisualTreeHelper.GetChildrenCount(depObj); i++)
            {
                DependencyObject child = VisualTreeHelper.GetChild(depObj, i);
                if (child != null && child is T)
                {
                    yield return (T)child;
                }

                foreach (T childOfChild in FindVisualChildren<T>(child))
                {
                    yield return childOfChild;
                }
            }
        }
    }  
}

公共密封部分类主页面：第页
{
ObservableCollection_people=新的ObservableCollection（）；
int_personCount=0；
int_maxPeopleCount=7；
公共主页（）
{
this.InitializeComponent（）；
this.DataContext=\u人；
Window.Current.SizeChanged+=当前_SizeChanged；
} 
public void resize（）
{ 
var listpersonheight=listperson.ActualHeight；
IEnumerable items=FindVisualChildren（listperson）；
对于（int i=0；i  public class Person : INotifyPropertyChanged
{

    public Person(string firstName, string lastName)
    {
         FirstName = firstName;
        LastName = lastName;
    }


    private string _firstName = string.Empty;
    public string FirstName
    {
        get { return _firstName; }
        set
        {
            _firstName = value;
            OnPropertyChanged();
        }
    }


    private string _lastName = string.Empty;
    public string LastName
    {
        get { return _lastName; }
        set
        {
            _lastName = value;
            OnPropertyChanged();
        }
    }

    protected void OnPropertyChanged([CallerMemberName] string caller = "")
    {
        PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(caller));
    }

    public event PropertyChangedEventHandler PropertyChanged;


}

<Grid Background="{ThemeResource ApplicationPageBackgroundThemeBrush}" x:Name="gridroot">
    <Grid.ColumnDefinitions>
        <ColumnDefinition Width="*"/>
        <ColumnDefinition Width="*"/>
    </Grid.ColumnDefinitions>
    <Grid.RowDefinitions>
        <RowDefinition Height="*"/>
        <RowDefinition Height="*"/>
    </Grid.RowDefinitions>
    <Button Grid.Row="0" Grid.Column="0" x:Name="btnAddPerson" Click="btnAddPerson_Click" Content="Add Person" VerticalAlignment="Center" HorizontalAlignment="Center"/>
    <ListView x:Name="listperson"  BorderBrush="Black"  BorderThickness="5" Margin="10" Grid.Row="1" Grid.Column="0" ItemsSource="{Binding}" ScrollViewer.VerticalScrollMode="Disabled" ScrollViewer.VerticalScrollBarVisibility="Hidden" ScrollViewer.HorizontalScrollBarVisibility="Hidden" ScrollViewer.HorizontalScrollMode="Disabled" VerticalAlignment="Stretch"  VerticalContentAlignment="Stretch" HorizontalAlignment="Stretch" HorizontalContentAlignment="Stretch">
        <ListView.ItemContainerStyle>
            <Style TargetType="ListViewItem">
                <Setter Property="HorizontalContentAlignment" Value="Stretch"/>
                <Setter Property="VerticalContentAlignment" Value="Stretch"/>
                <Setter Property="MinHeight" Value="20"/>
                <Setter Property="Padding" Value="0"/>
            </Style>
        </ListView.ItemContainerStyle>
        <ListView.ItemsPanel>
            <ItemsPanelTemplate>
                <ItemsStackPanel HorizontalAlignment="Stretch"/>
            </ItemsPanelTemplate>
        </ListView.ItemsPanel>
        <ListView.ItemTemplate>
            <DataTemplate>
                <Grid x:Name="grdPerson" Loaded="grdPerson_Loaded" >
                    <Grid.ColumnDefinitions>
                        <ColumnDefinition Width="*"/>
                        <ColumnDefinition Width="*"/>
                    </Grid.ColumnDefinitions>
                    <Border Grid.Column="0" Background="Green" HorizontalAlignment="Stretch" >
                        <Viewbox>
                            <TextBlock Text="{Binding FirstName}" HorizontalAlignment="Stretch" />
                        </Viewbox>
                    </Border>
                    <Border Grid.Column="1" Background="Yellow" HorizontalAlignment="Stretch">
                        <Viewbox>
                            <TextBlock Text="{Binding LastName}" HorizontalAlignment="Stretch"  />
                        </Viewbox>
                    </Border>
                </Grid>
            </DataTemplate>
        </ListView.ItemTemplate>
    </ListView>
</Grid>

public sealed partial class MainPage : Page
{
    ObservableCollection<Person> _people = new ObservableCollection<Person>();
    int _personCount = 0;
    int _maxPeopleCount = 7;
    public MainPage()
    {
        this.InitializeComponent();
        this.DataContext = _people;
        Window.Current.SizeChanged += Current_SizeChanged;
    } 
    public void resize()
    { 
        var listpersonheight = listperson.ActualHeight; 
        IEnumerable<ListViewItem> items = FindVisualChildren<ListViewItem>(listperson);
        for (int i = 0; i < items.Count(); i++)
        {
            foreach (ListViewItem item in items)
            {
                item.Height = (listpersonheight - 10) / _maxPeopleCount;// BorderThickness size need to be minus.
                item.Width = listperson.ActualWidth - 10; //Width also need resize.
            }
        }
    }
    private void Current_SizeChanged(object sender, Windows.UI.Core.WindowSizeChangedEventArgs e)
    {
        resize();
    }
    private void grdPerson_Loaded(object sender, RoutedEventArgs e)
    {
        resize();
    }
    private void btnAddPerson_Click(object sender, RoutedEventArgs e)
    { 
        if (_people.Count == _maxPeopleCount)
        {
            _people.RemoveAt(_people.Count - 1);
        }
        _personCount += 1; 
        _people.Insert(0, new Person($"FirstName {_personCount}", $"LastName {_personCount}")); 
    }

    private static IEnumerable<T> FindVisualChildren<T>(DependencyObject depObj) where T : DependencyObject
    {
        if (depObj != null)
        {
            for (int i = 0; i < VisualTreeHelper.GetChildrenCount(depObj); i++)
            {
                DependencyObject child = VisualTreeHelper.GetChild(depObj, i);
                if (child != null && child is T)
                {
                    yield return (T)child;
                }

                foreach (T childOfChild in FindVisualChildren<T>(child))
                {
                    yield return childOfChild;
                }
            }
        }
    }  
}

<Setter Property="VerticalContentAlignment" Value="Stretch"/>

public class UniformStackPanel : StackPanel
{
    protected override Size MeasureOverride(Size availableSize)
    {
        var childSize = Orientation == Orientation.Horizontal ?
            new Size(availableSize.Width / Children.Count, availableSize.Height) :
            new Size(availableSize.Width, availableSize.Height / Children.Count);

        double alongAxis = 0;
        double crossAxis = 0;

        foreach (var child in Children)
        {
            child.Measure(childSize);

            if (Orientation == Orientation.Horizontal)
            {
                alongAxis += child.DesiredSize.Width;
                crossAxis = Math.Max(crossAxis, child.DesiredSize.Height);
            }
            else
            {
                alongAxis += child.DesiredSize.Height;
                crossAxis = Math.Max(crossAxis, child.DesiredSize.Width);
            }
        }

        return Orientation == Orientation.Horizontal ?
            new Size(alongAxis, crossAxis) :
            new Size(crossAxis, alongAxis);
    }

    protected override Size ArrangeOverride(Size finalSize)
    {
        var childSize = Orientation == Orientation.Horizontal ?
            new Size(finalSize.Width / Children.Count, finalSize.Height) :
            new Size(finalSize.Width, finalSize.Height / Children.Count);

        double alongAxis = 0;

        foreach (var child in Children)
        {
            if (Orientation == Orientation.Horizontal)
            {
                child.Arrange(new Rect(alongAxis, 0, childSize.Width, childSize.Height));
                alongAxis += childSize.Width;
            }
            else
            {
                child.Arrange(new Rect(0, alongAxis, childSize.Width, childSize.Height));
                alongAxis += childSize.Height;
            }
        }

        return finalSize;
    }
}

<ItemsControl BorderBrush="Black" BorderThickness="5" Margin="10" Grid.Row="1" ItemsSource="{Binding}" HorizontalAlignment="Stretch" VerticalAlignment="Stretch">
    <ItemsControl.ItemsPanel>
        <ItemsPanelTemplate>
            <local:UniformStackPanel/>
        </ItemsPanelTemplate>
    </ItemsControl.ItemsPanel>
    <ItemsControl.ItemTemplate>
        <DataTemplate>
            <Grid>
                <Grid.ColumnDefinitions>
                    <ColumnDefinition/>
                    <ColumnDefinition/>
                </Grid.ColumnDefinitions>
                <Border Grid.Column="0" Background="RoyalBlue" HorizontalAlignment="Stretch">
                    <Viewbox>
                        <TextBlock Text="{Binding FirstName}"/>
                    </Viewbox>
                </Border>
                <Border Grid.Column="1" Background="Crimson" HorizontalAlignment="Stretch">
                    <Viewbox>
                        <TextBlock Text="{Binding LastName}"/>
                    </Viewbox>
                </Border>
            </Grid>
        </DataTemplate>
    </ItemsControl.ItemTemplate>
</ItemsControl>