[英]WPF data binding to Window DataContext object properties
** [已解决] **这是我在这里提出的第一个问题,因此可能会出现一些错误。 在我的WPF应用程序中,我想以“双向模式”将所有控件绑定到特殊对象实例BuildingManagementSystem
相应属性,我想将其设置为Window DataContext。 但是没有任何效果(不显示数据)。 绑定它的正确方法是什么?
这是我的代码:
public partial class MainWindow : Window
{
BuildingManagementSystem bms { get; set; }
public MainWindow()
{
InitializeComponent();
this.Loaded += new RoutedEventHandler(Window1_Loaded);
}
void Window1_Loaded(object sender, RoutedEventArgs e)
{
bms = new BuildingManagementSystem();
this.DataContext = bms;
}
public class BuildingManagementSystem
{
public string Name { get; set; }
public readonly FireAlarmSystem FireAlarmSystem;
public BuildingManagementSystem()
{
FireAlarmSystem = new FireAlarmSystem();
}
}
class FireAlarmSystem
{
private int alarmSmokeRate, currentSmokeRate;
public List<PowerConsumer> Devices { get; set; }
public int CurrentSmokeRate
{
get { return currentSmokeRate; }
set { SetField(ref currentSmokeRate, value, () => CurrentSmokeRate); }
}
public FireAlarmSystem()
{
Devices = new List<PowerConsumer>();
}
}
class PowerConsumer
{
public string Name { get; set; }
public double Power { get; set; }
public int Priority { get; set; }
public bool Enabled { get; set; }
}
XAML:
<DataGrid Name="FireAlarmGrid" HorizontalAlignment="Left" Margin="10,51,0,0" CanUserAddRows="True"
CanUserDeleteRows="True" VerticalAlignment="Top" AutoGenerateColumns="False" ItemsSource="{Binding FireAlarmSystem.Devices}" >
<DataGrid.RowValidationRules>
<local:FireValidationRule ValidationStep="UpdatedValue"/>
</DataGrid.RowValidationRules>
<DataGrid.Columns>
<DataGridCheckBoxColumn Header="Enabled" Binding="{Binding Enabled}"></DataGridCheckBoxColumn>
<DataGridTextColumn Header="Name" Binding="{Binding Name,ValidatesOnExceptions=True }" >
</DataGridTextColumn>
<DataGridTextColumn Header="Power" Binding="{Binding Power}"></DataGridTextColumn>
</DataGrid.Columns>
</DataGrid>
<TextBox Name="tbCurrentSmokeRate" Text="{Binding Path=FireAlarmSystem.CurrentSmokeRate, Mode=TwoWay}" VerticalAlignment="Top" Width="70"/>
我个人喜欢创建viewmodel的静态实例,如下所示:
<Window.Resources>
<ViewModels:MainWindowVM x:Key="VM"></ViewModels:MainWindowVM>
当我这样做时,绑定很容易,因为属性页面会在VS中为您找到属性。
<StackPanel Grid.Column="0" Margin="5,5,5,0"
DataContext="{Binding Source={StaticResource VM}}">
但是请记住,您需要添加名称空间
xmlns:ViewModels="clr-namespace:MyWPF.ViewModels"
xmlns:Views="clr-namespace:MyWPF.Views"
这样允许属性绑定如下:
<Views:UcTitle x:Name="XTitle" ></Views:UcTitle>
<Views:UcLegendTitle x:Name="XLegendTitle"/>
<Views:UcSeriesTitle x:Name="XSeriesTitle" />
<Views:UcSeriesTypes x:Name="XSeriesTypes"/>
而且您不必在其中键入任何名称。在您的情况下,您没有使用ViewModel,而是在正确设置数据上下文。 因此,这只能是无数据显示或属性绑定不正确。 请记住,要使此功能起作用,您需要三件事:1)DataContext 2)Vales和3)按名称正确绑定...这是刚开始使用强大的WPF绑定系统时引起很多人关注的第三点。
要使MVVM工作...
您将需要更新您的视图模型以实现INotifyPropertyChanged,以使WPF知道您的属性已更改
使用ObservableCollections而不是列表,ObservableCollections具有让Datagrid listview的连线,列表框知道集合中的项已更改
将字段更改为属性,以便WPF可以看到它...
<DataGrid Name="FireAlarmGrid" HorizontalAlignment="Left" Margin="10,51,0,0" CanUserAddRows="True"
CanUserDeleteRows="True" VerticalAlignment="Top" AutoGenerateColumns="False" ItemsSource="{Binding FireAlarmSystem.Devices}" >
<DataGrid.RowValidationRules>
<local:FireValidationRule ValidationStep="UpdatedValue"/>
</DataGrid.RowValidationRules>
<DataGrid.Columns>
<DataGridCheckBoxColumn Header="Enabled" Binding="{Binding Enabled,Mode=TwoWay}"></DataGridCheckBoxColumn>
<DataGridTextColumn Header="Name" Binding="{Binding Name,ValidatesOnExceptions=True,Mode=TwoWay }" >
</DataGridTextColumn>
<DataGridTextColumn Header="Power" Binding="{Binding Power,Mode=TwoWay}"></DataGridTextColumn>
</DataGrid.Columns>
</DataGrid>
<TextBox Name="tbCurrentSmokeRate" Text="{Binding Path=FireAlarmSystem.CurrentSmokeRate, Mode=TwoWay}" VerticalAlignment="Top" Width="70"/>
public class BuildingManagementSystem : INotifyPropertyChanged
{
private string _Name;
public string Name
{
get { return _Name; }
set
{
if (_Name != value)
{
_Name = value;
PropertyChanged(this, new PropertyChangedEventArgs("Name"));
}
}
}
private FireAlarmSystem _fireAlarmSystem;
public FireAlarmSystem FireAlarmSystem { get { return _fireAlarmSystem; } }
public BuildingManagementSystem()
{
_fireAlarmSystem = new FireAlarmSystem();
}
#region INotifyPropertyChanged Members
public event PropertyChangedEventHandler PropertyChanged = delegate { };
#endregion
}
public class FireAlarmSystem : INotifyPropertyChanged
{
private int alarmSmokeRate, currentSmokeRate;
public ObservableCollection<PowerConsumer> Devices { get; set; }
public int CurrentSmokeRate
{
get { return currentSmokeRate; }
set
{
//SetField(ref currentSmokeRate, value, () => CurrentSmokeRate);
PropertyChanged(this, new PropertyChangedEventArgs("CurrentSmokeRate"));
}
}
public FireAlarmSystem()
{
Devices = new ObservableCollection<PowerConsumer>();
//Create some test data...
Devices.Add(new PowerConsumer() { Name = "One", Enabled = true, Power = 100, Priority = 1 });
Devices.Add(new PowerConsumer() { Name = "two", Enabled = false, Power = 101, Priority = 2 });
Devices.Add(new PowerConsumer() { Name = "three", Enabled = false, Power = 103, Priority = 3 });
}
#region INotifyPropertyChanged Members
public event PropertyChangedEventHandler PropertyChanged = delegate { };
#endregion
}
public class PowerConsumer
{
public string Name { get; set; }
public double Power { get; set; }
public int Priority { get; set; }
public bool Enabled { get; set; }
}
这里有几个错误
代替BuildingManagementSystem bms {get; 组; 编写以下代码:
BuildingManagementSystem bms = new BuildingManagementSystem();
归功于所有,我发现了一个错误,那就是将FireAlarmSystem
定义为readonly
,它应该是一个属性。 2 Stuart Smith,您使用INotifyPropertyChanged
是正确的,但是我有一个抽象的class-ancestor BuildingSystem
,它实现了此接口。 我忘记发布了。
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