WPF数据绑定到Window DataContext对象属性

本文关键字：对象 属性 DataContext Window 数据绑定 WPF | 更新日期: 2023-09-27 18:26:40

**[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中的相应属性，我想将其设置为Window DataContext。但什么都不起作用（数据不显示）。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"/>

WPF数据绑定到Window DataContext对象属性

我个人喜欢创建视图模型的静态实例，如下所示：

<Window.Resources>
    <ViewModels:MainWindowVM x:Key="VM"></ViewModels:MainWindowVM>

当我这样做时，绑定很容易，因为属性页面在VS中为您找到属性。

 <StackPanel Grid.Column="0" Margin="5,5,5,0"  
          DataContext="{Binding Source={StaticResource VM}}">

但请记住，您需要添加名称空间

 xmlns:ViewModels="clr-namespace:MyWPF.ViewModels" 
 xmlns:Views="clr-namespace:MyWPF.Views"

这允许像这样的属性绑定：

    <Views:UcTitle x:Name="XTitle" ></Views:UcTitle>
    <Views:UcLegendTitle x:Name="XLegendTitle"/>
    <Views:UcSeriesTitle x:Name="XSeriesTitle" />
    <Views:UcSeriesTypes x:Name="XSeriesTypes"/>

而且你不必在。。。在您的情况下，您没有使用ViewModel，但您正确地设置了数据上下文。因此，这只能是没有要显示的数据或不正确的属性绑定。记住，要做到这一点，你需要三件事：1）DataContext 2）Vales和3）按名称正确绑定。。。这是第三个，当刚开始使用伟大的WPF绑定系统时，人们会经常绊倒它。

这里有几个错误

  1. 似乎BuildingManagementSystem旨在成为您的数据上下文

代替BuildingManagementSystem bms｛get；set；｝编写以下代码：

BuildingManagementSystem bms=新建BuildingManagement系统（）；

  1. 您需要在ViewModels中实现INotifyPropertyChanged事件，以反映UI上的更改
  2. 如果您打算为每个底层子视图模型分配值，请使用参数化构造函数来传递和分配值。简单地在父视图中实例化子视图模型是没有任何作用的

要使MVVM工作。。。

您需要更新您的视图模型以实现INotifyPropertyChanged，让wpf知道您的属性已更改

使用Observable集合而不是列表，ObservableCollections有连线让Datagrid列表查看，列表框知道集合中的项目已经更改

将字段更改为属性，这样WPF就会看到它…

<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; }
}

感谢大家，我发现了一个错误，它将FireAlarmSystem定义为readonly，它应该是一个属性。2 Stuart Smith，您对INotifyPropertyChanged是正确的，但我有一个抽象类祖先BuildingSystem，它实现了这个接口。我忘了贴了。

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