【发布时间】：2023-03-24 23:10:02
【问题描述】：
我有一个类ParamObj（它实现了INotifyPropertyChanged），它包含一个DefaultValues 类型的ObservableCollection<Param> 属性。我的Param 类（也实现了INotifyPropertyChanged）包含两个属性：Name 和IsSelected。
单击按钮时，我正在使用TextBlock 和ComboBox 控件填充StackPanel。集合DefaultValues 中的每个Param 都是ComboBox 中的一个选项，其中Name 属性表示该选项的文本，IsSelected 是一个布尔值，表示该选项是否是当前在ComboBox.
Param 类如下：
public class Param : INotifyPropertyChanged
{
public enum ParamType
{
Unknown=-1,
Text=0,
Option=1,
Multi=2
}
private string pName = string.Empty;
private bool pSelected = false;
private ParamType pType = ParamType.Unknown;
public string Name { get { return pName; } set { pName = value; OnPropertyChanged("Name"); } }
public bool IsSelected { get { return pSelected; } set { pSelected = value; OnPropertyChanged("IsSelected"); } }
public ParamType Type { get { return pType; } }
public Param(string name, bool selected)
{
this.pName = name;
this.pSelected = selected;
this.pType = ParamType.Option;
}
//INotifyPropertyChanged base
public event PropertyChangedEventHandler PropertyChanged;
protected void OnPropertyChanged(string name)
{
PropertyChangedEventHandler handler = PropertyChanged;
if (handler != null)
handler(this, new PropertyChangedEventArgs(name));
}
}
ParamObj 下面的类：
public class ParamObj : INotifyPropertyChanged
{
//ui type mapping
public enum UITypeEnum
{
Textbox = 0,
ComboBox = 1,
CheckableComboBox = 2
}
private string name = string.Empty;
private UITypeEnum uiType = UITypeEnum.Textbox;
private ObservableCollection<Param> defaultVals = new ObservableCollection<Param>();
private string propDescription = string.Empty;
public string Name { get { return name; } set { name = value; OnPropertyChanged("Name"); } }
public UITypeEnum UIType { get { return uiType; } set { uiType = value; OnPropertyChanged("UIType"); } }
public ObservableCollection<Param> DefaultValues { get { return defaultVals; } }
public string Desc { get { return propDescription; } set { propDescription = value; } }
//Initialization
public ParamObj()
{
}
public void ClearDefaultValues()
{
this.defaultVals.Clear();
OnPropertyChanged("DefaultValues");
}
public void AddDefaultValue(Param objAdded)
{
this.defaultVals.Add(objAdded);
}
public void AddDefaultValueRange(Param[] objsToAdd)
{
foreach (Param o in objsToAdd)
{
this.defaultVals.Add(o);
}
}
//INotifyPropertyChanged base
public event PropertyChangedEventHandler PropertyChanged;
protected void OnPropertyChanged(string name)
{
PropertyChangedEventHandler handler = PropertyChanged;
if (handler != null)
handler(this, new PropertyChangedEventArgs(name));
}
}
在按钮单击事件中调用下面的代码。 po 代表一个 ParamObj 实例。
case ParamObj.UITypeEnum.ComboBox:
cb = new ComboBox();
cb.Height = 26;
cb.Width = 210;
cb.Margin = new Thickness(2);
cb.VerticalContentAlignment = System.Windows.VerticalAlignment.Center;
cb.DataContext = po.DefaultValues;
//binding
cb.ItemsSource = po.DefaultValues;
cb.DisplayMemberPath = "Name";
cb.SelectedValuePath = "IsSelected";
cb.SelectedValue = true;
cb.SelectionChanged += ParamComboBox_SelectionChanged;
break;
这就是问题所在。 ComboBox 项目已成功填充，并选择了 IsSelected 值为 true 的选项（Param 对象）。我想会发生的是，当我更改ComboBox 中的选定选项时，Param 对象的IsSelected 属性值（布尔值）将从false 切换到true。这没有发生。所以我将cb.SelectionChanged += ParamComboBox_SelectionChanged 事件添加到ComboBox。
private void ParamComboBox_SelectionChanged(object sender, SelectionChangedEventArgs e)
{
if (!(sender is ComboBox)) return;
ComboBox cb = sender as ComboBox;
Param cp = (Param)cb.SelectedItem;
if (cp.IsSelected == false)
{
foreach (Param p in cb.ItemsSource)
{
p.IsSelected = false;
}
cp.IsSelected = true;
}
}
通过调试，我确实看到IsSelected 属性已正确更新，但我的po 对象中的值并未使用新值进行更新。
非常感谢任何建议。我已经尽了最大的努力来解决这个问题，但我被卡住了。
布赖恩
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