WPF XAML試圖綁定DataGrid列的寬度

Question

我想將我的列的寬度綁定到我的模型中的屬性，以便在用戶調整大小時將其保存起來。我想要一個沒有代碼的解決方案。 這是我到目前爲止有：

XAML：

<DataGrid x:Name="dgArticles" AutoGenerateColumns="False" ItemsSource="{Binding Specifications.Articles}" RowDetailsVisibilityMode="Visible"> 
     <DataGrid.Columns> 
      <DataGridTextColumn x:Name="Number" Header="Number" Binding="{Binding Number}" Width="{Binding RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type UserControl}}, Path=DataContext.Specifications.Config.NumberColumnWidth}" MinWidth="70" > 

型號：

public class Specifications 
{ 
    private ConfigurationGrid config 
    public ConfigurationGrid Config { get { return config; } set { } } 

    private ObservableCollection<Article> articles; 
    public ObservableCollection<Article> Articles 
    { 
     get { return articles; } 
     set { } 
    } 


public class ConfigurationGrid : INotifyPropertyChanged 
{ 
    private double numberColumnWidth; 
    public double NumberColumnWidth 
    { 
     get { return numberColumnWidth; } 
     set { numberColumnWidth = value; OnPropertyChanged("numberColumnWidth"); } 
    } 

    public ConfigurationGrid() { } 

    public event PropertyChangedEventHandler PropertyChanged; 

    private void OnPropertyChanged(string propertyName) 
    { 
     if (PropertyChanged != null) 
      PropertyChanged(this, 
       new System.ComponentModel.PropertyChangedEventArgs(propertyName)); 
    } 
} 

我設法綁定一個子DataGrid列是在寬度我將RowDetailsTemplate設置爲另一列的寬度，如下所示：

<DataGridTextColumn Header="Quantity" CellStyle="{StaticResource QuantityStyle}" Binding="{Binding Quantity, UpdateSourceTrigger=PropertyChanged, StringFormat=\{0:n\}}" 
                Width="{Binding Source={x:Reference Mesure}, Path=ActualWidth}"/> 

這工作正常，但我不知道爲什麼它不在我的主要DataGrid上工作。 調試後，我發現它甚至沒有達到NumberColumnWidth的Getter。 有誰知道一種方法使其工作？謝謝

編輯

我試圖通過@ MM8所提供的解決方案，但沒有奏效。它仍然沒有達到Getter。也許我錯過了什麼。下面是代碼看起來像現在：

XAML：

<UserControl x:Class="CachView.Views.GridView" 
     xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" 
     xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" 
     xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" 
     xmlns:d="http://schemas.microsoft.com/expression/blend/2008" 
     xmlns:sys="clr-namespace:System;assembly=mscorlib" 
     xmlns:local="clr-namespace:CachView.ViewModels" 
     xmlns:conv="clr-namespace:CachView.Converters" 
     xmlns:util="clr-namespace:CachView.Util" 
     mc:Ignorable="d" 
     d:DesignHeight="300" d:DesignWidth="300"> 

<UserControl.DataContext> 
    <local:ArticleViewModel/> 
</UserControl.DataContext> 

<Grid Margin="10"> 
    <DataGrid x:Name="dgArticles" AutoGenerateColumns="False" ItemsSource="{Binding Specifications.Articles}" RowDetailsVisibilityMode="Visible"> 
     <DataGrid.Resources> 
      <util:BindingProxy x:Key="proxy" Data="{Binding}"/> 
     </DataGrid.Resources> 
     <DataGrid.Columns> 
      <DataGridTextColumn x:Name="Number" Header="Number" Binding="{Binding Number}" Width="{Binding Data.Specifications.Config.NumberColumnWidth, Source={StaticResource proxy}}" 
           MinWidth="70"> 

      </DataGridTextColumn> 

後面的代碼：

public partial class GridView : UserControl 
{ 
    public GridView(ArticleViewModel a) 
    {    
     InitializeComponent(); 
     this.DataContext = a; 
    } 
} 

而且我BindingProxy類是相同的例子：

class BindingProxy : Freezable 
{ 
    protected override Freezable CreateInstanceCore() 
    { 
     return new BindingProxy(); 
    } 

    public object Data 
    { 
     get { return (object)GetValue(DataProperty); } 
     set { SetValue(DataProperty, value); } 
    } 


    public static readonly DependencyProperty DataProperty = 
     DependencyProperty.Register("Data", typeof(object), typeof(BindingProxy), new UIPropertyMetadata(null)); 
} 

我的項目是一個用戶控件，用於從WinForm應用程序中使用。這是它是如何實現的，以及如何設置DataContext和屬性。它是從我的WinForm應用程序的控制器完成的。

class Controller 
{ 

    private ArticleViewModel articleViewModel; 
    private ElementHost elementHost; 
    private MainWindow winformView; 
    public ArticleViewModel ArticleViewModel { get { return articleViewModel; } } 
    public Collection<Article> Articles { get; set; } 
    public Specifications Specs { get; set; }  

    public Controleur(MainWindow view) // The view is received from Program.cs 
    { 
     this.winformView = view; 
     Articles = new Collection<Article>(); 
     populateArticles(); // This create hard coded articles for testing purpose 

     ConfigurationGrid config= new ConfigurationGrid(); 
     config.NumberColumnWidth = 300; 

     Specs = new Specifications(Articles); 
     Specs.Config = config; 

     articleViewModel = new ArticleViewModel(Specs); 


     GridView gridView = new GridView(articleViewModel); //This is my WPF UserControl 

     elementHost = new ElementHost(); 
     elementHost.Dock = DockStyle.Fill; 
     this.winformView.Controls.Add(elementHost); 
     elementHost.Child = gridView;   
    } 

我的視圖模型：

public class ArticleViewModel 
{ 
    private Specifications specifications; 
    public Specifications Specifications { get { return specifications; } set { } } 



    public ArticleViewModel() { } 

    public ArticleViewModel(Specifications c) 
    { 
     this.specifications = c; 
    } 
} 

任何幫助或建議表示歡迎。

Answer 1

A DataGridTextColumn不是被添加到元素樹的可視元素，因此您將無法綁定到RelativeSource，因爲沒有祖先可以綁定到該元素。

如果您希望能夠將Width屬性綁定到視圖模型屬性，則可以使用BindingProxy對象捕獲DataContext，如以下博客文章中所建議的。

[WPF]如何綁定到數據時，不繼承的DataContext：https://www.thomaslevesque.com/2011/03/21/wpf-how-to-bind-to-data-when-the-datacontext-is-not-inherited/