wpf 如何将基于 Key 的 Dictionary Value 绑定到 Code-Behind 中的 TextBlock？

How do I bind Dictionary Value based on Key to a TextBlock in Code-Behind?

提问by Bob.

I am using the MVVM model with a dynamic field generator, where the field is pulled from the database, done this way because different types of forms require different fields (TextBox/TextBlock, ComboBox, etc.). The problem is I'm trying to retrieve a value from a dictionary, to display in a TextBlock for the form, but I'm not sure how to bind the retrieved Key so I can display the value.

我正在使用带有动态字段生成器的 MVVM 模型，其中字段是从数据库中提取的，这样做是因为不同类型的表单需要不同的字段（TextBox/TextBlock、ComboBox 等）。问题是我试图从字典中检索一个值，以在表单的 TextBlock 中显示，但我不确定如何绑定检索到的 Key 以便我可以显示该值。

Currently, I am doing the following:

目前，我正在做以下事情：

 TextBlock textBlock = new TextBlock();
 textBlock.SetBinding(TextBlock.TextProperty, createFieldBinding(myPropertyName);

With the following binding method:

使用以下绑定方法：

 private Binding createFieldBinding(string fieldName) {
      Binding binding = new Binding(fieldName);
      binding.Source = this.DataContext;
      binding.UpdateSourceTrigger = UpdateSourceTrigger.LostFocus;
      return binding;
 }

Where I pass something through like Score, which maps to a Scoreproperty in the ViewModel, but how would I bind to a Dictionary Key to retrieve its Value?

我通过 like 传递一些东西Score，它映射到ScoreViewModel 中的一个属性，但是我如何绑定到字典键来检索它的值？

I want to be able to bind to something like myDictionaryProperty[myDictionaryKey], if that is possible.

myDictionaryProperty[myDictionaryKey]如果可能的话，我希望能够绑定到类似的东西。

Example: The below generates the PlayerScorefor Player with ID of 1. Where PlayerScoreis a Dictionary<int, int>and PlayerIDis an int.

示例：下面生成PlayerScoreID 为 1的for Player。其中PlayerScore是 aDictionary<int, int>和PlayerID是int。

 <TextBlock Name="textBlockA" Text="{Binding PlayerScore[1]} />

回答by Arthur Nunes

Binding to indexed properties is possible and uses the same notation as C#, just like you wrote:

绑定到索引属性是可能的，并且使用与 C# 相同的符号，就像你写的一样：

<TextBlock Name="textBlockA" Text="{Binding PlayerScore[1]}" />

The string you pass to "createFieldBinding" is the property path. If you set the source as the dictionary, you just need to pass the indexer part, like "[1]", as if you had done like this in xaml:

您传递给“createFieldBinding”的字符串是属性路径。如果将源设置为字典，则只需要传递索引器部分，例如“[ 1]”，就好像您在 xaml 中这样做一样：

<TextBlock Name="textBlockA" Text="{Binding [1]}" />

See this

看到这个

回答by Bob.

Using this solutionprovided by @Clemens, I was able to build my own DictionaryItemConverter, based on the data types for my Dictionary, and create a multi-binding method that would bind the Keyand the Dictionarytogether.

使用@Clemens 提供的这个解决方案，我能够基于我的 Dictionary 的数据类型构建我自己的 DictionaryItemConverter，并创建一个将 theKey和 the绑定Dictionary在一起的多绑定方法。

Converter:

转换器：

 public class DictionaryItemConverter : IMultiValueConverter {
      public object Convert(object[] values, Type targetType, object parameter, System.Globalization.CultureInfo culture) {
           if(values != null && values.Length >= 2) {
                var myDict = values[0] as IDictionary;
                if(values[1] is string) {
                     var myKey = values[1] as string;
                     if(myDict != null && myKey != null) {
                          //the automatic conversion from Uri to string doesn't work
                          //return myDict[myKey];
                          return myDict[myKey].ToString();
                     }
                }
                else {
                     long? myKey = values[1] as long?;
                     if(myDict != null && myKey != null) {
                          //the automatic conversion from Uri to string doesn't work
                          //return myDict[myKey];
                          return myDict[myKey].ToString();
                     }
                }
           }

           return Binding.DoNothing;
      }

      public object[] ConvertBack(object value, Type[] targetTypes, object parameter, System.Globalization.CultureInfo culture) {
           throw new NotSupportedException();
      }
 }

Multi-Bind Method:

多重绑定方法：

 private MultiBinding createFieldMultiBinding(string fieldName) {
      // Create the multi-binding
      MultiBinding mbBinding = new MultiBinding();
      // Create the dictionary binding
      Binding bDictionary = new Binding(fieldName + "List");
      bDictionary.Source = this.DataContext;
      // Create the key binding
      Binding bKey = new Binding(fieldName);
      bKey.Source = this.DataContext;
      // Set the multi-binding converter
      mbBinding.Converter = new DictionaryItemConverter();
      // Add the bindings to the multi-binding
      mbBinding.Bindings.Add(bDictionary);
      mbBinding.Bindings.Add(bKey);

      return mbBinding;
 }