启用/禁用按钮,按行在网格中
本文关键字:网格 按钮 启用 | 更新日期: 2023-09-27 17:53:03
我有以下代码。这里listClear
是一个对象,由ViewModel填充。我用这个物体的属性来填充一个Grid
。在下面的代码中,我应该使用什么属性来使Button
在DataTrigger
中禁用。当Grid
为空时,我希望Button
被禁用,否则它应该被启用。
<Button Grid.Column="3" Margin="2" Command="{Binding Path=ClearCommand}" Content="Clear">
<Button.Style>
<Style TargetType="Button">
<Setter Property="IsEnabled" Value="True" />
<Style.Triggers>
<DataTrigger Binding="{Binding Path=listClear}" Value="">
<Setter Property="IsEnabled" Value="False"/>
</DataTrigger>
</Style.Triggers>
</Style>
</Button.Style>
</Button>
您可以使用List
Count
属性来表示空
的例子:
public partial class MainWindow : Window
{
private ObservableCollection<string> myVar = new ObservableCollection<string>();
public MainWindow()
{
InitializeComponent();
MyList.Add("test");
}
public ObservableCollection<string> MyList
{
get { return myVar; }
set { myVar = value; }
}
private void Button_Click(object sender, RoutedEventArgs e)
{
MyList.Clear();
}
}
Xaml:
<Window x:Class="WpfApplication11.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:local="clr-namespace:WpfApplication11"
Title="MainWindow" Height="136.3" Width="208" x:Name="UI">
<Grid DataContext="{Binding ElementName=UI}">
<Button Content="Clear" Click="Button_Click">
<Button.Style>
<Style TargetType="Button">
<Setter Property="IsEnabled" Value="True" />
<Style.Triggers>
<DataTrigger Binding="{Binding Path=MyList.Count}" Value="0">
<Setter Property="IsEnabled" Value="False"/>
</DataTrigger>
</Style.Triggers>
</Style>
</Button.Style>
</Button>
</Grid>
</Window>
如果你只使用IEnumerable<T>
,这有点困难,因为IEnumerable
没有公共属性可以绑定,你必须做一个转换器。
像这样
public class IsEmptyConverter : IValueConverter
{
public object Convert(object value, Type targetType, object parameter, CultureInfo culture)
{
if (value is IEnumerable)
{
var enumerable = (IEnumerable)value;
foreach (var item in enumerable)
{
return false;
}
}
return true;
}
public object ConvertBack(object value, Type targetType, object parameter, CultureInfo culture)
{
throw new NotImplementedException();
}
}
Xaml: <Window x:Class="WpfApplication11.MainWindow"
xmlns:local="clr-namespace:Namespace for converter"
....
....
<Window.Resources>
<local:IsEmptyConverter x:Key="IsEmptyConverter" />
</Window.Resources>
....
....
<DataTrigger Binding="{Binding Path=MyList, Converter={StaticResource IsEmptyConverter}}" Value="true">