调用当前对象上的方法

Im attempting to bind to the output of a method. Now I've seen examples of this using ObjectDataProvider However the problem with this is ObjectDataProvider creates a new instance of the object to call the method. Where I need the method called on the current object instance. I'm currently trying to get a converter to work.

我试图绑定到方法的输出。现在我已经看到了使用ObjectDataProvider的例子，但是这个问题是ObjectDataProvider创建一个对象的新实例来调用这个方法。我需要在当前对象实例中调用该方法。我目前正在尝试让一个转换器工作。

Setup:

设置:

Class Entity
{
   private Dictionary<String, Object> properties;

   public object getProperty(string property)
  {
      //error checking and what not performed here
     return this.properties[property];
  }
}

My attempt at the XAML

我尝试了XAML

     <local:PropertyConverter x:Key="myPropertyConverter"/>
      <TextBlock Name="textBox2">
          <TextBlock.Text>
            <MultiBinding Converter="{StaticResource myPropertyConverter}"
                          ConverterParameter="Image" >
              <Binding Path="RelativeSource.Self" /> <!--this doesnt work-->
            </MultiBinding>
          </TextBlock.Text>
        </TextBlock>

my code behind

我的代码在

public object Convert(object[] values, Type targetType, object parameter, CultureInfo culture)
{
    string param = (string)parameter;
    var methodInfo = values[0].GetType().GetMethod("getProperty", new Type[0]);
    if (methodInfo == null)
        return null;
    return methodInfo.Invoke(values[0], new string[] { param });               
}

public object[] ConvertBack(object value, Type[] targetTypes, object parameter, CultureInfo culture)
{
    throw new NotSupportedException("PropertyConverter can only be used for one way conversion.");
}

My problem is that I cant seem to pass the current Entity into the converter. So When i try to use reflection to get the getProperty method I have nothing to operate on

我的问题是我似乎不能将当前的实体传递给转换器。所以当我尝试使用反射来获取getProperty方法时，我没有任何操作。

thanks, steph

谢谢你,史蒂芬

1 个解决方案

#1

Wrap the call to the method inside a get property and add this get property to whatever class that is your current DataContext.

在get属性中封装对方法的调用，并将这个get属性添加到当前DataContext的任何类中。

Edit: Answering your updated question.

编辑:回答你的问题。

If you only pass one parameter to the valueconverter you don't need a multivalueconverter, just use a regular valueconverter (implementing IValueConverter). Also, why not cast the object in the valueconverter to a Distionary and use it directly instead of using reflection.

如果您只将一个参数传递给valueconverter，那么您不需要一个multivalueconverter，只需使用一个常规的valueconverter(实现IValueConverter)。同样，为什么不将valueconverter中的对象转换为一个蒸馏器，并直接使用它，而不是使用反射。

To pass current datacontext as a binding do this: <Binding . />. I'm guessing the datacontext of the textblock is entity.

要将当前的datacontext作为绑定传递，请执行以下操作: <绑定。> 。我猜textblock的datacontext是entity。

Still, all this is not necessary if all you want to do is run some code before accessing a dictionary item. Just use an index property instead, you can databind to it directly:

不过，如果您只想在访问字典项之前运行一些代码，那么所有这些都不是必需的。只需使用一个索引属性，就可以直接对其进行数据库:

public class Entity 
{ 
   private Dictionary<String, Object> properties; 

   public object this[string property]
   {
        get
        { 
            //error checking and what not performed here 
            return properties[property]; 
        }
    } 
} 

<TextBlock Text="{Binding Path=[Image]}" />

#1