c# - 导致 xamDataGrid 重新绘制

Question

我需要一种方法让 View 模型指示 View 上的 XamDataGrid 以最少的麻烦重新读取和重新绘制其单元格。我不想弄乱源代码并做一些不可持续的解决方法来引发它的事件(源代码可能会改变)。

为了让它更容易理解，我有一个全局静态类，它包含一些视觉提示配置，这些配置不会影响数据，但只会影响它们在网格中的表示方式(缩放、格式化等)。视觉操作发生在附加到工作正常的字段的 IValueConverter 实现中。有一个静态事件，当提示发生变化并且 View 模型订阅它并且事件正确触发时会触发。现在我只需要让事件处理程序使网格重新绘制。

有什么建议吗？

编辑:一些代码，如果有帮助的话:

转换器:

public class ScaleConverter : IValueConverter
{
    public object Convert(object value, Type targetType, object parameter, CultureInfo culture)
    {
        if (targetType == typeof(double) || targetType == typeof(double?))
        {
            if (value == null && targetType == typeof(double?)) return null;  // short circuit for null->null, nothing to scale
            if (value is double) return (double)value / DisplayScale.Scale; // shortcut for direct scaling, no need to waste time on conversion
            try
            {
                return System.Convert.ToDouble(value) / DisplayScale.Scale; // for convertible values, eat conversion exception
            }
            catch (Exception) {};
            // if all esle fails return NaN
            return double.NaN; 
        }
        // fallthrough, return null, this should not happen, if it does it means converter is incomplete
        return null;
    }
 ...
}

全局显示比例

public class DisplayScale: NotificationObject
{
    private static KeyValuePair<string, double> _ActiveScaling;
    private static readonly object _lockHandle = new object(); // note: should not contest, but just to be on the safe side
    public static event Action ScalingChanged;

    public static List<KeyValuePair<string, double>> ScaleList { get; private set; }

    static DisplayScale()
    {
        ScaleList = new List<KeyValuePair<string, double>>() 
        { 
            new KeyValuePair<string, double>("No scaling (1's)", 1d),
            new KeyValuePair<string, double>("Thousands (1,000's)", 1000d),
            new KeyValuePair<string, double>("Millions (1,000,000's)", 1000000d),
            new KeyValuePair<string, double>("Billions (1,000,000,000's)", 1000000000d)
         };
        ActiveScaling = ScaleList.First();  // OPTION: could be in per-user config
    }

    public static double Scale { get { return ActiveScaling.Value; } }
    public static KeyValuePair<string, double> ActiveScaling
    {
        get
        {
            lock (_lockHandle) return _ActiveScaling;
        }
        set
        {
            lock (_lockHandle)
            {
                _ActiveScaling = value;
                var eventCall = ScalingChanged;
                if (eventCall != null) eventCall();
            }
        }
    }
}

字段定义为

// resource
<inf:ScaleConverter x:Key="ScaleConverter" />
// field
<igDP:Field Name="Deposit" Converter="{StaticResource ScaleConverter}">

Answer 1

如果你有一个 collectionview 而不是简单地调用它的 Refresh()。

public class YourViewModel
{
  private ObservableCollection<YourDataClass> yourColl;

  public void YourViewModel()
  {
    yourColl = new ObservableCollection<YourDataClass>();
    YourCollectionView = CollectionViewSource.GetDefaultView(yourColl);
    DisplayScale.ScalingChanged += () => YourCollectionView.Refresh();
  }

  var ICollectionView yourCollView;
  public ICollectionView YourCollectionView
  {
    get { yourCollView; }
    set {
      yourCollView = value;
      RaisePropertyChanged("YourCollectionView");
    }
  }
}