當綁定到MainView窗口的寬度屬性時綁定錯誤

Question

我有一個MainView窗口，其寬度和高度我試圖從其代碼隱藏類綁定。

<Window x:Class="RpP25.MainView" 
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" 
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" 
    xmlns:shared="http://schemas.actiprosoftware.com/winfx/xaml/shared"  
    xmlns:docking="http://schemas.actiprosoftware.com/winfx/xaml/docking" 
    xmlns:themes="http://schemas.actiprosoftware.com/winfx/xaml/themes" 
    xmlns:RpWin="clr-namespace:RpP25" 
    xmlns:RpWinCmds="clr-namespace:RpP25.Commands" 
    xmlns:diagnostics="clr-namespace:System.Diagnostics;assembly=WindowsBase" 
    Title="{Binding Path=FileName, Converter={StaticResource WindowTitleNameConverter}}" 
    Height="{Binding Path=WindowHeight, RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type Window}}}" 
    Width="{Binding Path=WindowWidth, RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type Window}}}" 
    Icon="images/CobWhite.ico" 
    Loaded="Window_Loaded" 
    Closing="Window_Closing"> 

後面的代碼具有屬性，並通過ViewModel MainVM設置datacontext。

public partial class MainView : Window, INotifyPropertyChanged 
{ 
    // Constant Fields 
    private const double windowDefaultWidth_ = 720; 
    private const double windowDefaultHeight_ = 400; 

    // Private Fields 
    private RegistryKey RegKey_;        // Registry Key to hold Registry Subkey 
    private WindowState windowState_ = WindowState.Normal; // Display State of the MainWindow (Min,Max or Normal) 
    private double windowWidth_ = windowDefaultWidth_; // Width of the MainWindow 
    private double windowHeight_ = windowDefaultHeight_; // Height of the MainWindow 

    #region Constructors 

    public MainView() 
    { 
     InitializeComponent(); 
     DataContext = new MainVM(); 

     // Get the state of the window and the width/height from the registry 
     ReadRegistryValues(); 

    /// <summary> 
    /// Gets the Width of the Window 
    /// </summary> 
    public double WindowWidth 
    { 
     get { return windowWidth_; } 
     set { windowWidth_ = value; NotifyPropertyChanged("WindowWidth"); } 
    } 

    /// <summary> 
    /// Gets the Height of the Window 
    /// </summary> 
    public double WindowHeight 
    { 
     get { return windowHeight_; } 
     set { windowHeight_ = value; NotifyPropertyChanged("windowHeight"); } 
    } 

    ... 
} 

此窗口創建自App::OnStartup()。

當我運行代碼時，調試器會在輸出窗口中引發以下錯誤。

找不到與參考'RelativeSource FindAncestor，AncestorType ='System.Windows.Window'，AncestorLevel ='1'綁定的源代碼。 BindingExpression：路徑= WINDOWHEIGHT;的DataItem = NULL;目標元素是'MainView'（Name =''）;目標屬性是'高度'（類型'Double'）

和類似的WindowWidth。

我想我理解結合模式，但我想我錯了:(

我的想法是使用FindAncestor尋找一個窗口會導致它來查找視覺樹，直到它找到的MainView窗口對是我的特性。

任何幫助將非常感激。

Answer 1

嘗試

Width="{Binding Path=WindowWidth, RelativeSource={RelativeSource Self}}" 

代碼隱藏相同ELEM恩你的窗戶。所以使用自我約束。