在DataTemplate中發現DynamicResource綁定

Question

是否可以發現數據模板中的所有動態資源 - 在數據模板本身內，還是在將其應用於某個ContentPresenter之後？

我的想法是讓某種屬性編輯器編輯wpf對象的外觀（可能使用XamlReader動態創建），並顯示 - 對於某個對象，只顯示相應DataTemplate中使用的資源項。

Answer 1

到目前爲止，我還沒有找到一個「乾淨」的方式來使用框架方法來獲取動態資源。

但是，有一種可能性是使用反射搜索DataTemplate。動態資源存儲在類型爲System.Windows.ChildValueLookup的結構中，其中LookupType是「資源」。我寫了一個輔助類來枚舉資源：

using System; 
using System.Collections.Generic; 
using System.Diagnostics; 
using System.Linq; 
using System.Reflection; 
using System.Windows; 

namespace DashboardTest 
{ 
    public struct ResourceInfo 
    { 
     public ResourceInfo(string resourceKey, DependencyProperty property) 
      : this() 
     { 
      ResourceKey = resourceKey; 
      Property = property; 
     } 

     public string ResourceKey { get; private set; } 
     public DependencyProperty Property { get; set; } 
    } 

    public static class DataTemplateHelper 
    { 
     private static readonly Type ChildValueLookupType = GetType("System.Windows.ChildValueLookup"); 
     private static readonly FieldInfo LookupTypeField = ChildValueLookupType.GetField("LookupType", BindingFlags.Instance | BindingFlags.NonPublic); 
     private static readonly FieldInfo ValueField = ChildValueLookupType.GetField("Value", BindingFlags.Instance | BindingFlags.NonPublic); 
     private static readonly FieldInfo PropertyField = ChildValueLookupType.GetField("Property", BindingFlags.Instance | BindingFlags.NonPublic); 
     private static readonly object LookupTypeResource = Enum.Parse(LookupTypeField.FieldType, "Resource"); 

     public static List<ResourceInfo> FindDynamicResources(DataTemplate template) 
     { 
      var recordField = typeof(DataTemplate).GetField("ChildRecordFromChildIndex", BindingFlags.Instance | BindingFlags.NonPublic); 
      Debug.Assert(recordField != null); 

      var values = EnumerateObjects(recordField.GetValue(template)).Where(IsDynamicResource).Select(ToResourceInfo).ToList(); 
      return values; 
     } 

     private static ResourceInfo ToResourceInfo(object lookup) 
     { 
      return new ResourceInfo((string)ValueField.GetValue(lookup), (DependencyProperty)PropertyField.GetValue(lookup)); 
     } 

     private static Type GetType(string typeName) 
     { 
      foreach (Assembly assembly in AppDomain.CurrentDomain.GetAssemblies()) 
      { 
       Type type = assembly.GetType(typeName); 
       if (type != null) 
        return type; 
      } 
      return null; 
     } 

     private static bool IsDynamicResource(object obj) 
     { 
      if (obj == null || obj.GetType() != ChildValueLookupType) return false; 
      return LookupTypeResource.Equals(LookupTypeField.GetValue(obj)); 
     } 

     private static IEnumerable<object> EnumerateObjects(object obj) 
     { 
      var visited = new HashSet<object>(); 
      EnumerateObjectsInternal(obj, visited, 20); 
      return visited; 
     } 

     private static void EnumerateObjectsInternal(object obj, HashSet<object> visited, int maxDepth) 
     { 
      if (obj == null || maxDepth <= 0) return; 
      var type = obj.GetType(); 

      if (obj is Type || obj is string || obj is DateTime || type.IsPrimitive 
       || type.IsEnum || visited.Add(obj) == false) return; 

      var array = obj as Array; 
      if (array != null) 
      { 
       foreach (var item in array) 
       { 
        EnumerateObjectsInternal(item, visited, maxDepth - 1); 
       } 
      } 
      else 
      { 
       foreach (var field in GetAllFields(type)) 
       { 
        var fieldValue = field.GetValue(obj); 
        EnumerateObjectsInternal(fieldValue, visited, maxDepth - 1); 
       } 
      } 
     } 

     private static IEnumerable<FieldInfo> GetAllFields(Type type) 
     { 
      const BindingFlags bindingFlags = BindingFlags.Public | BindingFlags.NonPublic | BindingFlags.Instance | BindingFlags.DeclaredOnly; 

      if (type == typeof(object) || type.BaseType == typeof(object)) 
      { 
       return type.GetFields(bindingFlags); 
      } 
      else 
      { 
       var fieldInfoList = new List<FieldInfo>(); 

       var currentType = type; 
       while (currentType != typeof(object)) 
       { 
        fieldInfoList.AddRange(currentType.GetFields(bindingFlags)); 
        currentType = currentType.BaseType; 
       } 
       return fieldInfoList; 
      } 
     } 
    } 
} 

Answer 2

請看Snoop實用程序。您可以查看源代碼並查看如何查看任何對象的樣式/模板並更改其外觀。