我在Listview中有一个GridView
Griview内部有几个GridViewColumn。
现在我想隐藏这些列之一
我写了这个：
<Grid>
<ListView>
<ListView.View>
<GridView>
<GridViewColumn Header="First" Width="100"/>
<GridViewColumn Header="Second" Width="0"/>
<GridViewColumn Header="Third" Width="100"/>
<GridViewColumn Header="Fourth" Width="100"/>
</GridView>
</ListView.View>
</ListView>
</Grid>
Initially it is hidden, though i can still see the second column if i extend the third column separator.有什么方法可以设置GridViewColumn的可见性吗？
最佳答案
请尝试下一个解决方案。由于DataGridColumns不在DataGrid可视树中，因此必须使用替代方法来实现对诸如Visibility之类的属性的绑定。换句话说，您需要使用代理。这是为我工作的方式。
1. Xaml代码：
<Window x:Class="DataGridSoHelpAttempt.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:dataGridSoHelpAttempt="clr-namespace:DataGridSoHelpAttempt"
xmlns:i="http://schemas.microsoft.com/expression/2010/interactivity"
Title="MainWindow" Height="350" Width="525" x:Name="This">
<Window.DataContext>
<dataGridSoHelpAttempt:MainViewModel/>
</Window.DataContext>
<Grid x:Name="MyGrid">
<Grid.Resources>
<dataGridSoHelpAttempt:FreezableProxyClass x:Key="ProxyElement" ProxiedDataContext="{Binding Source={x:Reference This}, Path=DataContext}"/>
</Grid.Resources>
<DataGrid x:Name="MyDataGrid" ItemsSource="{Binding DataSource}" AutoGenerateColumns="False">
<DataGrid.Columns>
<DataGridTextColumn Header="Name" Binding="{Binding Name}"/>
<DataGridTextColumn Header="Description" Binding="{Binding Description}" Visibility="{Binding Source={StaticResource ProxyElement},
Path=ProxiedDataContext.Visibility, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}"></DataGridTextColumn>
<DataGridTextColumn Header="Comments" Binding="{Binding Comments}" Width="150"/>
</DataGrid.Columns>
</DataGrid>
<Button HorizontalAlignment="Stretch" VerticalAlignment="Bottom" Content="Show Description" Command="{Binding Command}"></Button>
</Grid>
2. FreezableProxyClass代码：
public class FreezableProxyClass : Freezable
{
protected override Freezable CreateInstanceCore()
{
return new FreezableProxyClass();
}
public static readonly DependencyProperty ProxiedDataContextProperty = DependencyProperty.Register(
"ProxiedDataContext", typeof (object), typeof (FreezableProxyClass), new PropertyMetadata(default(object)));
public object ProxiedDataContext
{
get { return (object) GetValue(ProxiedDataContextProperty); }
set { SetValue(ProxiedDataContextProperty, value); }
}
}
3. ViewModel代码：
public class MainViewModel:BaseObservableObject
{
private Visibility _visibility;
private ICommand _command;
public MainViewModel()
{
Visibility = Visibility.Collapsed;
DataSource = new ObservableCollection<BaseData>(new List<BaseData>
{
new BaseData {Name = "Uncle Vania", Description = "A.Chekhov, play", Comments = "worth reading"},
new BaseData {Name = "Anna Karenine", Description = "L.Tolstoy, roman", Comments = "worth reading"},
new BaseData {Name = "The Master and Margarita", Description = "M.Bulgakov, novel", Comments = "worth reading"},
});
}
public ICommand Command
{
get
{
return _command ?? (_command = new RelayCommand(VisibilityChangingCommand));
}
}
private void VisibilityChangingCommand()
{
Visibility = Visibility == Visibility.Collapsed ? Visibility.Visible : Visibility.Collapsed;
}
public ObservableCollection<BaseData> DataSource { get; set; }
public Visibility Visibility
{
get { return _visibility; }
set
{
_visibility = value;
OnPropertyChanged();
}
}
}
public class BaseData:BaseObservableObject
{
private string _name;
private string _description;
private string _comments;
public virtual string Name
{
get { return _name; }
set
{
_name = value;
OnPropertyChanged();
}
}
public virtual object Description
{
get { return _description; }
set
{
_description = (string) value;
OnPropertyChanged();
}
}
public string Comments
{
get { return _comments; }
set
{
_comments = value;
OnPropertyChanged();
}
}
}
4. MVVM零件
public class BaseObservableObject : INotifyPropertyChanged
{
public event PropertyChangedEventHandler PropertyChanged;
protected virtual void OnPropertyChanged([CallerMemberName] string propertyName = null)
{
var handler = PropertyChanged;
if (handler != null) handler(this, new PropertyChangedEventArgs(propertyName));
}
protected virtual void OnPropertyChanged<T>(Expression<Func<T>> raiser)
{
var propName = ((MemberExpression)raiser.Body).Member.Name;
OnPropertyChanged(propName);
}
protected bool Set<T>(ref T field, T value, [CallerMemberName] string name = null)
{
if (!EqualityComparer<T>.Default.Equals(field, value))
{
field = value;
OnPropertyChanged(name);
return true;
}
return false;
}
}
public class RelayCommand : ICommand
{
private readonly Func<bool> _canExecute;
private readonly Action _execute;
public RelayCommand(Action execute)
: this(() => true, execute)
{
}
public RelayCommand(Func<bool> canExecute, Action execute)
{
_canExecute = canExecute;
_execute = execute;
}
public bool CanExecute(object parameter = null)
{
return _canExecute();
}
public void Execute(object parameter = null)
{
_execute();
}
public event EventHandler CanExecuteChanged;
}
5.外观如何：
如果您的代码有问题，我们将很乐意为您提供帮助。
问候。
更新
1. Xaml代码：
<Window x:Class="DataGridSoHelpAttempt.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:dataGridSoHelpAttempt="clr-namespace:DataGridSoHelpAttempt"
xmlns:i="http://schemas.microsoft.com/expression/2010/interactivity"
Title="MainWindow" Height="350" Width="525" x:Name="This">
<Window.Resources>
<dataGridSoHelpAttempt:ColumnObject2ColumnConverter x:Key="ColumnObject2ColumnConverterKey" />
</Window.Resources>
<Window.DataContext>
<dataGridSoHelpAttempt:MainViewModel/>
</Window.DataContext>
<Grid x:Name="MyGrid">
<Grid.Resources>
<dataGridSoHelpAttempt:FreezableProxyClass x:Key="ProxyElement" ProxiedDataContext="{Binding Source={x:Reference This}, Path=DataContext}"/>
</Grid.Resources>
<Grid>
<ListView ItemsSource="{Binding DataSource}">
<ListView.View>
<GridView>
<GridView.Columns>
<GridViewColumn Header="Name" DisplayMemberBinding="{Binding Name}" Width="100"/>
<dataGridSoHelpAttempt:MyGridViewColumn Visibility="{Binding Visibility}" DefaultWidth="100" Header="Description" DisplayMemberBinding="{Binding Description}" Width="100"/>
<GridViewColumn Header="Comments" DisplayMemberBinding="{Binding Comments}" Width="100"/>
</GridView.Columns>
</GridView>
</ListView.View>
</ListView>
</Grid>
<!--<DataGrid x:Name="MyDataGrid" ItemsSource="{Binding DataSource}" AutoGenerateColumns="False">
<DataGrid.Columns>
<DataGridTextColumn Header="Name" Binding="{Binding Name}"/>
<DataGridTextColumn Header="Description" Binding="{Binding Description}" Visibility="{Binding Source={StaticResource ProxyElement},
Path=ProxiedDataContext.Visibility, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}"></DataGridTextColumn>
<DataGridTextColumn Header="Comments" Binding="{Binding Comments}" Width="150"/>
</DataGrid.Columns>
</DataGrid>-->
<Button HorizontalAlignment="Stretch" VerticalAlignment="Bottom" Content="Show Description" Command="{Binding Command}"></Button>
</Grid></Window>
2. MyGridViewColumn代码：
public class MyGridViewColumn : GridViewColumn
{
protected override void OnPropertyChanged(DependencyPropertyChangedEventArgs e)
{
base.OnPropertyChanged(e);
}
public static readonly DependencyProperty DefaultWidthProperty = DependencyProperty.Register(
"DefaultWidth", typeof (double), typeof (MyGridViewColumn), new PropertyMetadata(default(double)));
public double DefaultWidth
{
get { return (double) GetValue(DefaultWidthProperty); }
set { SetValue(DefaultWidthProperty, value); }
}
/// <summary>
/// Width DependencyProperty
/// </summary>
public new static readonly DependencyProperty WidthProperty =
FrameworkElement.WidthProperty.AddOwner(
typeof(MyGridViewColumn),
new PropertyMetadata(
Double.NaN /* default value */,
new PropertyChangedCallback(OnWidthChanged))
);
public static readonly DependencyProperty VisibilityProperty =
UIElement.VisibilityProperty.AddOwner(typeof (MyGridViewColumn),
new PropertyMetadata(Visibility.Visible, new PropertyChangedCallback(Target)));
private static double _zeroValue = 0d;
private static void Target(DependencyObject dependencyObject, DependencyPropertyChangedEventArgs args)
{
var column = dependencyObject as MyGridViewColumn;
var visibility = (Visibility)args.NewValue;
if (visibility == Visibility.Collapsed)
{
column.SetValue(WidthProperty, _zeroValue);
}
else if(visibility == Visibility.Visible)
{
column.SetValue(WidthProperty, column.DefaultWidth);
}
}
public Visibility Visibility
{
get { return (Visibility) GetValue(VisibilityProperty); }
set { SetValue(VisibilityProperty, value); }
}
/// <summary>
/// width of the column
/// </summary>
/// <remarks>
/// The default value is Double.NaN which means size to max visible item width.
/// </remarks>
[TypeConverter(typeof(LengthConverter))]
public double Width
{
get { return (double)GetValue(WidthProperty); }
set { SetValue(WidthProperty, value); }
}
private static void OnWidthChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
{
MyGridViewColumn c = (MyGridViewColumn)d;
var visibility = c.Visibility;
if(visibility == Visibility.Collapsed)
c.Width = _zeroValue;
double newWidth = (double)e.NewValue;
c.OnPropertyChanged(new PropertyChangedEventArgs(WidthProperty.Name));
}
}
外观如何：
问候。