c# - WPF从DataTrigger更改图像

Question

首先，值得一提的是，我研究了其他类似的主题，它们帮助我取得了长足的进步，但我需要一点帮助来克服终点。

我遇到的问题是我无法让我的DataTrigger显示正确的图像，当InPossesion bool标志设置为false时，我将枚举属性设置为IconImage2，这反过来又应该更改数据网格中的图像变成红色圆圈，这不会发生。如果有人能给我关于我要去哪里的任何指示，那将很棒。

ViewModel枚举

 public enum  IconEnum
 {
    IconImage1,
    IconImage2
 }

 public IconEnum MyIconEnumProperty
 {
   get { return _myEnum; }
   set
     {
       _myEnum = value;
        RaisePropertyChanged("MyIconEnumProperty");
     }
  }    

ViewModel方法加载订单

 private void LoadCloakroomOrders()
 {
     CloakroomOrderRepository repo = new CloakroomOrderRepository();
     //Get All orders
     var orders = repo.GetPublic();
     foreach (var orderItem in orders)
      {
          Orders.Add(orderItem);
          if (orderItem.InPossesion == false)
          {
              MyIconEnumProperty = IconEnum.IconImage2;
          }
      }
  }

XAML

<DataGrid AutoGenerateColumns="False" ItemsSource="{Binding Orders}" 
                  SelectedItem="{Binding Path=SelectedCloakroomOrder}"
                  Margin="0,23,0,-0.5" Width="980" >
            <DataGrid.Columns>
                <DataGridTemplateColumn>
                    <DataGridTemplateColumn.CellTemplate>
                        <DataTemplate>
                            <Image Visibility="{Binding ShowIcon,
                              Converter={StaticResource BooleanToVisibilityConverter},  
                              FallbackValue=hidden}" >
                               <Image.Style>
                                   <Style TargetType="Image">
                                       <Setter Property="Source" Value="/Resources/Images/circle_green.png"/>
                                        <Style.Triggers>
                                            <DataTrigger Binding="{Binding MyIconEnumProperty}" Value="IconImage2">
                                                <Setter Property="Source" Value="/Resources/Images/circle_red.png"></Setter>
                                            </DataTrigger>
                                        </Style.Triggers>
                                    </Style>
                               </Image.Style>
                           </Image>
                        </DataTemplate>
                  </DataGridTemplateColumn.CellTemplate>
              </DataGridTemplateColumn>
           </DataGrid.Columns>
      </DataGrid>

谢谢!

Answer 1

您可以仅具有InPossesion属性，然后基于该属性隐藏/显示两个图像，而不是在VM中具有枚举。这样可以使 View 模型更整洁，并使XAML更清晰:

ViewModel:

public bool InPossession
{
    get { return _inPossession; }
    set { _inPossion = value; RaisePropertyChanged("InPossession"); }
}

private void LoadCloakroomOrders()
{
    CloakroomOrderRepository repo = new CloakroomOrderRepository();
    //Get All orders
    var orders = repo.GetPublic();
    foreach (var orderItem in orders)
    {
        Orders.Add(orderItem);
        if (orderItem.InPossesion == false)
        {
            InPossession = false;
        }
    }
}

转换器:

public class BooleanToVisibilityConverter : IValueConverter
{
    public Visibility VisibilitIfTrue { get;set; }
    public Visibility VisibilitIfFalse { get;set; }

    public BooleanToVisibilityConverter()
    {
        // Set default values for the most common usage
        VisibilityIfTrue = Visible;
        VisibilityIfFalse = Collapsed;
    }

    public object Convert(object value, Type targetType, object parameter, CultureInfo culture)
    {

    // Converter could be extended to handle nullable bools as well, but ignore for now
    if (value == null)
    {
        return DependencyProperty.UnsetValue;
    }

    // value should be of type bool
    bool b = (bool)value;
    if (b == true)
    {
        return VisibilityIfTrue;
    }
    else
    {
        return VisibilityIfFalse;
    }
    }

    public object ConvertBack(object value, Type targetType, object parameter, CultureInfo culture)
    {
         throw new NotImplementedException(); // Not necessary
    }
}

XAML:

<UserControl>
    <UserControl.Resources>
        <converters:BooleanToVisibilityConverter x:Key="TrueToVisibleConverter" VisibilityIfTrue="Visible" VisibleIfFalse="Collapsed"/>
        <converters:BooleanToVisibilityConverter x:Key="FalseToVisibleConverter" VisibilityIfTrue="Collapsed" VisibleIfFalse="Visible"/>
    </UserControl.Resources>
</UserControl>
...
<DataTemplate>
    <Grid Visibility="{Binding ShowIcon, FallbackValue=hidden}">
         <Image Source="/Resources/Images/circle_green.png" Visibility="{Binding InPossession, Converter={StaticResource TrueToVisibleConverter}}"/>
         <Image Source="/Resources/Images/circle_red.png" Visibility="{Binding InPossession, Converter={StaticResource FalseToVisibleConverter}}"/>
    </Grid>
</DataTemplate>