我正在使用Xceed Extended WPF Toolkit在[Flags]
中显示包含PropertyGrid
属性的枚举。
[Flags]
public enum TestEnum
{
Test1 = 1,
Test2 = 2,
Test3 = 4,
Test4 = 8,
Test5 = 16,
Test6 = 32,
Test7 = 64,
}
因为我无法在编译时知道枚举定义,所以我会使用EnumBuilder动态创建枚举。
我创建了一个编辑器,将枚举显示为CheckComboBox
:
public class CheckComboBoxEditor : TypeEditor<CheckComboBox>, ITypeEditor
{
protected override void SetValueDependencyProperty()
{
ValueProperty = CheckComboBox.SelectedValueProperty;
}
protected override CheckComboBox CreateEditor()
{
return new CheckComboBox();
}
protected override void ResolveValueBinding(PropertyItem propertyItem)
{
var _binding = new Binding("Value");
_binding.Source = propertyItem;
_binding.UpdateSourceTrigger = UpdateSourceTrigger.PropertyChanged;
_binding.Mode = BindingMode.TwoWay;
_binding.Converter = CreateValueConverter();
BindingOperations.SetBinding(Editor, CheckComboBox.SelectedValueProperty, _binding);
var _binding2 = new Binding("Value");
_binding2.Source = propertyItem;
_binding2.UpdateSourceTrigger = UpdateSourceTrigger.PropertyChanged;
_binding2.Mode = BindingMode.TwoWay;
_binding2.Converter = CreateValueConverter();
BindingOperations.SetBinding(Editor, CheckComboBox.SelectedItemProperty, _binding2);
Editor.ItemsSource = Enum.GetValues(propertyItem.Value.GetType());
}
}
如您所见,到目前为止,我已尝试绑定SelectedValue
和SelectedItem
属性。 CreateValueConverter()
在基类中定义并返回null
。
如果我在框中选择一些值并点击我的保存按钮,那么效果很好 - 在我的模型中,我收到了正确的枚举值。但是在另一个方向上无效 - 如果我将任何枚举值(带或不带标记)设置为我的属性,则取消选中所有值并且内容区域为空
你有什么想法解决这个问题吗?
答案 0 :(得分:5)
对于具有FlagsAttribute的Enum,在这种情况下,最常见的解决方案是在VM中为Enum的所有项目和所选项目使用特定字段。这样的事情:
XAML
<Window.DataContext>
<local:MainWindowViewModel />
</Window.DataContext>
<Grid>
<xctkpg:PropertyGrid Grid.Row="1" SelectedObject="{Binding CurrentObject}" AutoGenerateProperties="False">
<xctkpg:PropertyGrid.EditorDefinitions>
<xctkpg:EditorTemplateDefinition TargetProperties="{x:Type local:TestEnum}">
<xctkpg:EditorTemplateDefinition.EditingTemplate>
<DataTemplate>
<xctk:CheckComboBox ItemsSource="{Binding Instance.Items}" SelectedValue="{Binding Instance.SelValue}" />
</DataTemplate>
</xctkpg:EditorTemplateDefinition.EditingTemplate>
</xctkpg:EditorTemplateDefinition>
</xctkpg:PropertyGrid.EditorDefinitions>
<xctkpg:PropertyGrid.PropertyDefinitions>
<xctkpg:PropertyDefinition TargetProperties="Value" />
</xctkpg:PropertyGrid.PropertyDefinitions>
</xctkpg:PropertyGrid>
</Grid>
C#
class MainWindowViewModel : INotifyPropertyChanged
{
public event PropertyChangedEventHandler PropertyChanged;
private ItemViewModel _currentObject = new ItemViewModel() { Value = TestEnum.Test3 | TestEnum.Test7 };
public ItemViewModel CurrentObject
{
get { return _currentObject; }
set
{
_currentObject = value;
PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(nameof(CurrentObject)));
}
}
}
public class ItemViewModel : INotifyPropertyChanged
{
public event PropertyChangedEventHandler PropertyChanged;
private TestEnum _value;
public TestEnum Value
{
get { return _value; }
set
{
_value = value;
PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(nameof(Value)));
PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(nameof(SelValue)));
}
}
public string SelValue
{
get
{
return String.Join(",", Enum.GetValues(typeof(TestEnum)).OfType<TestEnum>().Where(v => (_value & v) != 0).Select(v => v.ToString()));
}
set
{
_value = value.Split(new[] { ','}, StringSplitOptions.RemoveEmptyEntries).Select(s => s.Trim()).
Aggregate((TestEnum)0, (acc, val) => acc | (TestEnum)Enum.Parse(typeof(TestEnum), val));
PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(nameof(SelValue)));
PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(nameof(Value)));
}
}
public ObservableCollection<string> Items
{
get
{
return new ObservableCollection<string>(Enum.GetNames(typeof(TestEnum)));
}
}
}
更新31/01/2016 为了使代码适用于动态生成的Enum,我做了以下更改:
XAML
<xctkpg:EditorTemplateDefinition TargetProperties="Value">
C#
public class ItemViewModel : INotifyPropertyChanged
{
public event PropertyChangedEventHandler PropertyChanged;
public static readonly Type EnumType = GenerateEnumType();
private object _value;
public object Value
{
get { return _value; }
set
{
_value = value;
PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(nameof(Value)));
PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(nameof(SelValue)));
}
}
public string SelValue
{
get
{
return String.Join(",",
Enum.GetValues(EnumType).OfType<object>().Where(v => ((int)_value & (int)v) != 0).Select(v => v.ToString()));
}
set
{
var strings = value.Split(new[] { ',' }, StringSplitOptions.RemoveEmptyEntries).Select(s => s.Trim());
_value = Enum.ToObject(EnumType, strings.Aggregate(0, (acc, val) => acc | (int)Enum.Parse(EnumType, val)));
PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(nameof(SelValue)));
PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(nameof(Value)));
}
}
public ObservableCollection<string> Items
{
get
{
return new ObservableCollection<string>(Enum.GetNames(EnumType));
}
}
public static Type GenerateEnumType()
{
string asmNameString = "flags_enum";
// Create Base Assembly Objects
AppDomain appDomain = AppDomain.CurrentDomain;
AssemblyName asmName = new AssemblyName(asmNameString);
AssemblyBuilder asmBuilder = appDomain.DefineDynamicAssembly(asmName, AssemblyBuilderAccess.Run);
// Create Module and Enumeration Builder Objects
ModuleBuilder modBuilder = asmBuilder.DefineDynamicModule(asmNameString + "_module");
EnumBuilder enumBuilder = modBuilder.DefineEnum(asmNameString, TypeAttributes.Public, typeof(int));
Type fa = typeof(FlagsAttribute);
CustomAttributeBuilder attributeBuilder =
new CustomAttributeBuilder(fa.GetConstructor(new Type[0]), new object[0]);
enumBuilder.SetCustomAttribute(attributeBuilder);
for (int i = 0; i < 7; i++)
{
enumBuilder.DefineLiteral($"Test{i + 1}", 1 << i);
}
return enumBuilder.CreateType();
}
}
现在,对于ItemViewModel,Value可以这样设置:
ItemViewModel vm = new ItemViewModel();
vm.Value = Enum.ToObject(ItemViewModel.EnumType, 33);