Question

有没有人知道为什么绑定对DecodePixelWidth属性不起作用？当我通过xml设置它 - 一切正常 - 我看到缩放图像。当我使用绑定时 - 图像没有缩放。

<Image VerticalAlignment="Top" Width="2292" Stretch="None">
    <Image.Source>
         <BitmapImage UriSource="{Binding Src}" DecodePixelWidth="{Binding DecodePixelWidth}"  />
    </Image.Source>
</Image>

    public int DecodePixelWidth
    {
        get
        {
            return _decodePixelWidth;
        }
        set
        {
            if (value != _decodePixelWidth)
            {
                _decodePixelWidth = value;
                NotifyPropertyChanged("DecodePixelWidth");
            }
        }
    }

谢谢！

Answer 1

我遇到了同样的问题，我发现这个解决方案http://diegoparolin-codeplus.blogspot.it/2014/09/set-decodepixelheight-property-binding.html对我有用。

在我的MVVM WPF应用程序中，我想使用存储在app.config中的值调整位图图像的大小。因此，为此，我尝试将Image.Height属性和BitmapImage.DecodePixelHeight直接绑定到我的ViewModel，就像这样：

在app.config中

<?xml version="1.0" encoding="utf-8"?>
<configuration>   
  <appSettings>   
    <add key="DocumentsToBeFiledImageHeight" value="240"/>
    <add key="DocumentsToBeFiledImageDecodePixelHeight" value="240"/>
  </appSettings> 
</configuration>

然后在我的ViewModel中添加了这些属性

private int _documentsToBeFiledImageDecodePixelHeight;
public int DocumentsToBeFiledImageDecodePixelHeight
{
  get { return _documentsToBeFiledImageDecodePixelHeight; }
  set
  {
    if (value != _documentsToBeFiledImageDecodePixelHeight)
    {
      _documentsToBeFiledImageDecodePixelHeight = value;
      RaisePropertyChanged(DocumentsToBeFiledImageDecodePixelHeightPropertyName);
    }
  }
}

private double _documentsToBeFiledImageHeight;
public double DocumentsToBeFiledImageHeight
{
  get { return _documentsToBeFiledImageHeight; }
  set
  {
    if (value != _documentsToBeFiledImageHeight)
    {
      _documentsToBeFiledImageHeight = value;
      RaisePropertyChanged(DocumentsToBeFiledImageHeightPropertyName);
    }
  }
}

和此代码

DocumentsToBeFiledImageHeight = Convert.ToDouble（ConfigurationManager.AppSettings [“DocumentsToBeFiledImageHeight”]）;

DocumentsToBeFiledImageDecodePixelHeight = Convert.ToInt32（ConfigurationManager.AppSettings [“DocumentsToBeFiledImageDecodePixelHeight”]）;

然后在XAML中我添加了这段代码

<Image Grid.Row="0" Height="{Binding RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type Window}}, Path=DataContext.DocumentsToBeFiledImageHeight, UpdateSourceTrigger=PropertyChanged}"> 
   <Image.Source>
     <BitmapImage DecodePixelHeight="{Binding RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type Window}}, Path=DataContext.DocumentsToBeFiledImageDecodePixelHeight, UpdateSourceTrigger=PropertyChanged}" 
        UriSource="{Binding Path=FullName}" />
   </Image.Source>
</Image>

不幸的是它不起作用，似乎没有正确设置DecodePixelHeight属性。因此，我试图直接从app.config恢复该值。我在app.config文件的用户设置部分添加了这些参数

<userSettings>
  <Agest.AO.Client.Properties.Settings>
    <setting name="DocumentsToBeFiledImageDecodePixelHeight" serializeAs="String">
      <value>240</value>
    </setting>
    <setting name="DocumentsToBeFiledImageHeight" serializeAs="String">
      <value>240</value>
    </setting>
  </Agest.AO.Client.Properties.Settings>
</userSettings>

我以这种方式更改了XAML代码

xmlns:localme="clr-namespace:Agest.AO.Client.Properties" 

<Image Grid.Row="0" Height="{Binding Source={x:Static localme:Settings.Default}, Path=DocumentsToBeFiledImageHeight, Mode=OneWay}">
  <Image.Source>
    <BitmapImage DecodePixelHeight="{Binding Source={x:Static localme:Settings.Default}, Path=DocumentsToBeFiledImageDecodePixelHeight, Mode=OneWay}"
            UriSource="{Binding Path=FullName}" />
  </Image.Source>
</Image>

现在它可以正常工作，我可以直接在配置文件中设置值。

问候！

绑定和DecodePixelWidth属性

1 个答案: