WPF中的数据绑定按钮可见性不起作用
WPF中的数据绑定按钮可见性不起作用
提问于 2018-04-01 08:41:38
许多代码传入，其中一些可能是无用的，因为我尝试了很多事情来让它工作。
我正在尝试使按钮导出安装程序不可见，除非所选安装程序在IsDownloaded上的值为TRUE
所以我将从我的WPF开始
DataContext="{Binding Source={StaticResource TheViewModel}}"
Title="MainWindow" Height="458" Width="755">
<Window.Resources>
<ViewModel:BoolToVisibilityConverter x:Key="BoolToVisibilityConverter" />
<ViewModel:InstallerColorConverter x:Key="InstallerColorConverter" />
</Window.Resources>
<ListBox Height="300" Grid.Column="0" Grid.Row="0" SelectionMode="Single" ItemsSource="{Binding SelectedProduct.Installers}" SelectedItem="{Binding SelectedInstaller}" >
<ListBox.ItemTemplate>
<DataTemplate>
<StackPanel Orientation="Horizontal">
<Ellipse HorizontalAlignment="Right" Fill="{Binding InstallerRelativeToCurrent, Converter={StaticResource InstallerColorConverter}}" Margin="5,5,5,5 " Height="20" Width="20" Stroke="Black"></Ellipse>
<TextBlock Margin="5,0,5,0" Text="{Binding Name}" />
<TextBlock Text=" " />
<TextBlock Text="{Binding VersionNumber}" />
</StackPanel>
</DataTemplate>
</ListBox.ItemTemplate>
</ListBox>
<StackPanel Grid.Column="0" Grid.Row="1" Orientation="Horizontal" HorizontalAlignment="Stretch">
<Button Name="btnInstall" Margin="5,5,5,5" Height="50" Width="75" MouseDoubleClick="btnDownloadInstaller_MouseDoubleClick" >Download</Button>
<Button Name="btnExportInstaller" Visibility="{Binding Path=SelectedInstaller.IsDownloaded, RelativeSource={RelativeSource Mode=FindAncestor,AncestorType={x:Type Button}}, Converter={StaticResource BoolToVisibilityConverter}}" Margin="5,5,5,5" Height="50" Width="90" MouseDoubleClick="btnExportInstaller_MouseDoubleClick" >Export Installer</Button>
</StackPanel>其中要指出的主要内容是
<Button Name="btnExportInstaller" Visibility="{Binding Path=SelectedInstaller.IsDownloaded, RelativeSource={RelativeSource Mode=FindAncestor,AncestorType={x:Type Button}}, Converter={StaticResource BoolToVisibilityConverter}}" Margin="5,5,5,5" Height="50" Width="90" MouseDoubleClick="btnExportInstaller_MouseDoubleClick" >Export Installer</Button>和
<ViewModel:BoolToVisibilityConverter x:Key="BoolToVisibilityConverter" />现在在我的班上，BoolToVisibilityConver
public class BoolToVisibilityConverter : IValueConverter
{
public object Convert(object value, Type targetType,
object parameter, CultureInfo culture)
{
var booool = (bool)value;
if (booool)
return Visibility.Collapsed;
else
return Visibility.Visible;
}
public object ConvertBack(object value, Type targetType,
object parameter, CultureInfo culture)
{
// Do the conversion from visibility to bool
return Visibility.Collapsed;
}
}最后，在视图模型中，我有
private Visibility _IsVisible;
public Visibility IsVisible
{
get { return _IsVisible; }
set { _IsVisible = value; OnPropertyChanged(nameof(_SelectedInstaller.IsDownloaded)); }
}
private Products _SelectedProduct;
public Products SelectedProduct
{
get { return _SelectedProduct; }
set { _SelectedProduct = value; OnPropertyChanged(nameof(SelectedProduct)); }
private Installers _SelectedInstaller;
public Installers SelectedInstaller
{
get { return _SelectedInstaller; }
set { _SelectedInstaller = value; OnPropertyChanged(nameof(SelectedInstaller)); }它不能工作
我在控制台上看到这两个错误，但我不理解它们
System.Windows.Data Error: 1 : Cannot create default converter to perform 'one-way' conversions between types 'System.Boolean' and 'System.Windows.Visibility'. Consider using Converter property of Binding. BindingExpression:Path=SelectedProduct.IsInstalled; DataItem='ViewModel' (HashCode=26987408); target element is 'Grid' (Name=''); target property is 'Visibility' (type 'Visibility')
System.Windows.Data Error: 5 : Value produced by BindingExpression is not valid for target property.; Value='False' BindingExpression:Path=SelectedProduct.IsInstalled; DataItem='ViewModel' (HashCode=26987408); target element is 'Grid' (Name=''); target property is 'Visibility' (type 'Visibility')如果有人能指出我在这里做错了什么，我会永远爱你！
回答 1
Stack Overflow用户
发布于 2018-04-01 09:44:18
SOLVED..this是工作代码
<Window.Resources>
<ViewModel:BoolToVisibilityConverter x:Key="BoolToVisibilityConverter" />
<Button Name="btnExportInstaller" Visibility="{Binding SelectedInstaller.IsDownloaded , Converter={StaticResource BoolToVisibilityConverter}}" Margin="5,5,5,5" Height="50" Width="90" MouseDoubleClick="btnExportInstaller_MouseDoubleClick">Export Installer</Button>
public class BoolToVisibilityConverter : IValueConverter
{
public object Convert(object value, Type targetType,
object parameter, CultureInfo culture)
{
var booool = (bool)value;
if (booool == false)
return Visibility.Collapsed;
else
return Visibility.Visible;
}
public object ConvertBack(object value, Type targetType,
object parameter, CultureInfo culture)
{
if (value is Visibility && (Visibility)value == Visibility.Visible)
{
return true;
}
return false;
}
}内部视图模型
private Installers _SelectedInstaller;
public Installers SelectedInstaller
{
get { return _SelectedInstaller; }
set { _SelectedInstaller = value; OnPropertyChanged(nameof(SelectedInstaller)); }
private Visibility _IsVisible;
public Visibility IsVisible
{
get { return _IsVisible; }
set { _IsVisible = value; OnPropertyChanged(nameof(SelectedInstaller.IsDownloaded)); }
}页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持
原文链接：
https://stackoverflow.com/questions/49593769
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