[英]How can I bind to a property from the Selected Item of a ComboBox?
我试图创建一个用户控件,以允许用户在应用程序中定义自己的自定义线性渐变。
到目前为止,我有一个用户控件,该控件使用以下模型来定义渐变停止的集合:
public class StopSelectorModel : INotifyPropertyChanged {
#region Field Values
private Task _PropertyT;
private ObservableCollection<GradientStop> _Stops;
private GradientStop _SelectedStop;
public event PropertyChangedEventHandler PropertyChanged;
#endregion
#region Properties
/// <summary>
/// Get or Set Gradient Stop Collection.
/// </summary>
public ObservableCollection<GradientStop> Stops {
get { return this._Stops; }
set {
this._Stops = value;
this._SelectedStop = value.FirstOrDefault( );
this._PropertyT = Task.WhenAll( new Task[ ] {
this.OnPropertyChanged( "Stops" ),
this.OnPropertyChanged( "SelectedStop" )
} );
}
}
/// <summary>
/// Get or Set Selected Gradient Stop.
/// </summary>
public GradientStop SelectedStop {
get { return this._SelectedStop; }
set {
if ( value == null )
return;
if ( !this._Stops.Contains( value ) )
this._Stops.Add( value );
this._SelectedStop = value;
this._PropertyT = this.OnPropertyChanged( "SelectedStop" );
}
}
#endregion
#region Methods
protected async Task OnPropertyChanged( string P ) {
if ( this.PropertyChanged != null )
await this.PropertyChanged.Async( this, new PropertyChangedEventArgs( P ) );
}
#endregion
#region Constructors
/// <summary>
/// Declare instance of StopSelectorModel.
/// </summary>
/// <param name="Base">GradientStopCollection to wrap.</param>
public StopSelectorModel( ObservableCollection<GradientStop> Base ) { this.Stops = Base; }
/// <summary>
/// Declare default instance of StopSelectorModel.
/// </summary>
public StopSelectorModel( ) : this( new ObservableCollection<GradientStop>( new GradientStop[ ] {
new GradientStop( Colors.White, 0.0D ),
new GradientStop( Colors.Black, 1.0D )
} ) ) { }
#endregion
}
我将其用作ComboBox的DataContext(据我所知,ItemSource = Stops,SelectedItem = SelectedStop,双向绑定,用于此类操作的标准操作程序)。
我还有一个控件,该控件使用以下颜色模型定义颜色(基本上是4个滑动条):
/// <summary>
/// Wrapper for allowing complete databinding of a System.Windows.Media.Color struct.
/// </summary>
public class ColorModel : INotifyPropertyChanged {
private Task _PropertyT;
private Color _Color;
/// <summary>
/// Get or Set Context Color.
/// </summary>
public Color Color {
get { return this._Color; }
set {
this._Color = value;
this._PropertyT = Task.WhenAll( new Task[ ] {
this.OnPropertyChanged( "Color" ),
this.OnPropertyChanged( "ScA" ),
this.OnPropertyChanged( "ScR" ),
this.OnPropertyChanged( "ScG" ),
this.OnPropertyChanged( "ScB" ),
} );
}
}
/// <summary>
/// Get or Set Color ScA value.
/// </summary>
public double ScA {
get { return this._Color.ScA; }
set {
this._Color.ScA = ( float )value;
this._PropertyT = Task.WhenAll( new Task[ ] {
this.OnPropertyChanged( "Color" ),
this.OnPropertyChanged( "ScA" ),
} );
}
}
/// <summary>
/// Get or Set Color ScR value.
/// </summary>
public double ScR {
get { return this._Color.ScR; }
set {
this._Color.ScR = ( float )value;
this._PropertyT = Task.WhenAll( new Task[ ] {
this.OnPropertyChanged( "Color" ),
this.OnPropertyChanged( "ScR" ),
} );
}
}
/// <summary>
/// Get or Set Color ScG value.
/// </summary>
public double ScG {
get { return this._Color.ScG; }
set {
this._Color.ScG = ( float )value;
this._PropertyT = Task.WhenAll( new Task[ ] {
this.OnPropertyChanged( "Color" ),
this.OnPropertyChanged( "ScG" ),
} );
}
}
/// <summary>
/// Get or Set Color ScB value.
/// </summary>
public double ScB {
get { return this._Color.ScB; }
set {
this._Color.ScB = ( float )value;
this._PropertyT = Task.WhenAll( new Task[ ] {
this.OnPropertyChanged( "Color" ),
this.OnPropertyChanged( "ScB" ),
} );
}
}
protected async Task OnPropertyChanged( string P ) {
await this.PropertyChanged?.Async(
this, new PropertyChangedEventArgs( P ) ).DontBlock( );
}
public event PropertyChangedEventHandler PropertyChanged;
/// <summary>
/// Define ColorModel with default White Color.
/// </summary>
public ColorModel( ) : this( Colors.White ) { }
/// <summary>
/// Define ColorModel with provided color.
/// </summary>
/// <param name="C">Color to assign to ColorModel.</param>
public ColorModel( Color C ) { this.Color = C; }
}
因此,在这里...我如何将ComboBox的SelectedItem的Color属性与此ColorModel绑定在一起? (如有必要,将提供更多详细信息,但时间会很短)。
提前谢谢你的帮助...
为了清楚起见,我想将SelectedValue(Color)传递给控件,该控件将能够编辑该颜色。
因此,操作的顺序将是使ComboBox选择渐变停止点之一,然后(这是我需要帮助的地方)负责调整颜色值的控件。
如果我理解正确,那么您希望获得选择项目时显示的所选渐变颜色。
我将为其创建自己的DataTemplate,并在GradientStop中将颜色设置为运行时构建颜色的绑定。 取决于您是否希望所有组合框项目都着色,这可能会有所帮助: 我可以对WPF组合框中的所选项目使用与下拉部分中的项目不同的模板吗?
编辑
作为对编辑的回应:如果我理解正确的话,您将获得DataContext是UserControlModel的UserControl,其子级为StopSelectorModel,在这种情况下,我将设置SelectedGradientStop上的raising事件并在UserControlModel中处理此事件。
或者,如果不是儿童与父母的关系,则在设置SelectedGradientStop时,我将使用Messanger并发送消息。
事件和消息都必须包含描述应使用哪种颜色的对象。
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