0

在我的程序中，我正在动态创建要添加到 WPF 窗口中的画布中的图像。我的问题是：如何将 canvas.left 和 canvas.right 点绑定到类属性。

如果图像在运行时之前存在，我会在 XAML/WPF 中像这样制作和绑定它：

<Image Height="26" HorizontalAlignment="Left" Canvas.Left="{Binding left}" Canvas.Top="{Binding top}" Name="Image1" Stretch="Fill" VerticalAlignment="Top" Width="28" Source="/imageTest;component/Images/blue-pin-md.png" />

我在 VB.net 中有什么：

'Create array of images
Dim myImages(5) as myImage

For i = 0 to myImages.count - 1
   myImages(i) = New myImage
   'set datacontext if I can bind
   myImages(i).image.DataContext = myImages(i)
   canvas1.Children.Add(myImages(i).image)
Next

我的图像类：

Imports System.ComponentModel

Public Class myImage
    Implements INotifyPropertyChanged

    Public Event PropertyChanged As PropertyChangedEventHandler Implements INotifyPropertyChanged.PropertyChanged

    Private Sub NotifyPropertyChanged(ByVal info As String)
        RaiseEvent PropertyChanged(Me, New PropertyChangedEventArgs(info))
    End Sub

    Private Property _image as New Image
    Private Property _left As Double
    Private Property _top As Double
    Private Shared Property r As New Random()

    Public Sub New()
        _image.Width = 28
        _image.Height = 26
        _image.Source = New System.Windows.Media.Imaging.BitmapImage(New Uri("/imageTest;component/Images/blue-pin-md.png", UriKind.Relative))
        'the below works without binding if I just want to set and leave them in one place but I would like to bind them so that I can move them relative to other data
        '_left = r.Next(0, System.Windows.SystemParameters.PrimaryScreenWidth)
        '_top = r.Next(0, System.Windows.SystemParameters.PrimaryScreenHeight)
    End Sub

    Public ReadOnly Property image As Image
        Get
            Return _image
        End Get
    End Property

    Public ReadOnly Property left As Double
        Get
            Return _left
        End Get
    End Property

    Public ReadOnly Property top As Double
        Get
            Return _top
        End Get
    End Property

    'a possible move method that would take advantage of the binding
    Public Sub move()
        _top += 1
        _left += 1
        NotifyPropertyChanged("left")
        NotifyPropertyChanged("top")
    End Sub
4

2 回答 2

1

不知道如何在 VB 中编写它，但在 C# 中它看起来像这样：

var leftBinding = new Binding
{
    Path = new PropertyPath("left"),
    Source = myImages[i]
};
var topBinding = new Binding
{
    Path = new PropertyPath("top"),
    Source = myImages[i]
};
myImages[i].image.SetBinding(Canvas.LeftProperty, leftBinding);
myImages[i].image.SetBinding(Canvas.TopProperty, topBinding);

或者更简单，使用 DataContext：

myImages[i].image.DataContext = myImages[i];
myImages[i].image.SetBinding(Canvas.LeftProperty, "left");
myImages[i].image.SetBinding(Canvas.TopProperty, "top");
于 2012-12-04T17:50:35.723 回答
0

多亏了 Clemens C# 代码，我才能让它工作。下面是我使用的代码。.SetBindings( , ) 对我来说是关键。

For i = 0 To myImages.Count - 1
    myImages(i) = New myImage
    myImages(i).image.DataContext = myImages(i)
    myImages(i).image.SetBinding(Canvas.LeftProperty, "left")
    myImages(i).image.SetBinding(Canvas.TopProperty, "top")
    canvas1.Children.Add(myImages(i).image)
Next
于 2012-12-04T17:57:41.120 回答