我有两个单选按钮用作使用MVVM的UI中的radioButton List。第一次加载用户控件时，会选择一个单选按钮，并在UI中显示相关控件...现在，当我更改单选按钮时，UI不会更新。
以下是示例XAML：
<Label Grid.Column="0" Grid.Row="3" Content="Exchange Details:" Margin="3" VerticalContentAlignment="Center" Style="{StaticResource NormalLabelStyle}"></Label>
<Grid Grid.Column="1" Grid.Row="3" Width="200">
<Grid.ColumnDefinitions>
<ColumnDefinition Width="Auto"/>
<ColumnDefinition Width="20"/>
<ColumnDefinition Width="Auto"/>
</Grid.ColumnDefinitions>
<RadioButton GroupName="rdoExchange" Content="Basic" IsChecked="{Binding Path=ExchangeDetailsBasic}" Grid.Column="0" VerticalContentAlignment="Center" VerticalAlignment="Center"></RadioButton>
<RadioButton GroupName="rdoExchange" Content="Advanced" IsChecked="{Binding Path=ExchangeDetailsAdvanced}" Grid.Column="2" VerticalContentAlignment="Center" VerticalAlignment="Center"></RadioButton
</Grid>
<Label Grid.Column="3" Grid.Row="0" Content="Number of Mailbox Profiles:" VerticalContentAlignment="Center" Style="{StaticResource NormalLabelStyle}" Visibility="{Binding Path=IsAdvanced}" ></Label>
<telerik:RadNumericUpDown Grid.Column="4" Grid.Row="0" Margin="3" Value="{Binding Path=NumberofMailboxProfiles}" IsInteger="True" Minimum="1" Maximum="4" HorizontalAlignment="Left" Visibility="{Binding Path=IsAdvanced}">< /telerik:RadNumericUpDown>
以下是我的ViewModel代码：
private enum ExchangeDetails{
Basic,
Advanced
}
private bool isBasicMode = true;
public bool ExchangeDetailsBasic {
get {
return this.isBasicMode;
}
set {
if (value) {
this.applicationSpecificRequirements[ExchangeDetailsKey] = ExchangeDetails.Basic.ToString();
if (!this.isBasicMode) {
this.CheckBasicOrAdvancedSelecteAndDisplayView();
}
}
}
}
public bool ExchangeDetailsAdvanced {
get {
return !this.isBasicMode;
}
set {
if (value) {
this.applicationSpecificRequirements[ExchangeDetailsKey] = ExchangeDetails.Advanced.ToString();
this.CheckBasicOrAdvancedSelecteAndDisplayView();
}
}
}
public Visibility IsAdvanced { get; private set; }
private void CheckBasicOrAdvancedSelecteAndDisplayView() {
this.isBasicMode = this.applicationSpecificRequirements.ContainsKey(ExchangeDetailsKey) ? (this.applicationSpecificRequirements[ExchangeDetailsKey].Equals(ExchangeDetails.Basic.ToString()) ? true : false) : true;
this.IsAdvanced = this.isBasicMode ? Visibility.Collapsed : Visibility.Visible;
}
答案 0 :(得分：8)
单选按钮，组和绑定不会混合。令人惊讶的是，这是设计的。
有三种方法可以更改UI中绑定控件的值。一个是用户可以通过鼠标点击或按键自己完成。第二个是代码可以更改数据源的值，绑定将更新UI中的值。
第三种方法是在代码中明确设置值。如果这样做，您刚刚设置的控件上的绑定将被禁用。
这有点违反直觉。您希望新值被推送到数据源。设计假设是，如果您希望在数据源中更改值，则需要在数据源中更改它，并且您的代码正在操作UI，因为您想要它再受约束。这为您提供了一种手动覆盖绑定的简单方法 - 只需在代码中设置控件的值 - 这不会强迫您查找Binding对象并显式操作它。这有一定的意义。我想。
但它会产生单选按钮的问题。因为分组单选按钮会在代码中更改彼此的值。如果组中有三个单选按钮，并且一个单选按钮被检查，则单选按钮会找到组中的其他按钮并取消选中它们。如果你看一下Reflector中的代码，你可以看到这个。
所以会发生什么正是您所观察到的：您单击单选按钮并禁用绑定。
以下是你对此采取的措施 - 这实际上具有相当大的意义。不要使用组。您可以使用单选按钮，但仅限于其视觉样式。忽略他们的分组功能。
相反，在视图模型中实现使绑定的布尔属性互斥的逻辑，例如：
public bool Option1
{
set
{
_Option1 = value;
if (value)
{
Option2 = false;
Option3 = false;
}
OnPropertyChanged("Option1");
}
}
如果你考虑一下，无论如何这个逻辑真的不应该在视图中。因为它是逻辑，这就是视图模型的用途。因此，虽然这有点痛苦，但你可以安慰自己，从结构上来说这是正确的事情。
答案 1 :(得分：0)
如果在视图模型中实现了INotifyPropertyChanged，并且在XAML中设置了Binding Mode = TwoWay，则可以让绑定为您完成剩下的工作。
以下是使用您的一些代码的示例：
<Grid >
<Grid.ColumnDefinitions>
<ColumnDefinition Width="*"/>
<ColumnDefinition Width="*"/>
</Grid.ColumnDefinitions>
<Grid.RowDefinitions>
<RowDefinition/>
<RowDefinition/>
</Grid.RowDefinitions>
<RadioButton GroupName="rdoExchange" Content="Basic"
IsChecked="{Binding Path=ExchangeDetailsBasic, Mode=TwoWay}"
Grid.Column="0"
VerticalContentAlignment="Center"
VerticalAlignment="Center"/>
<RadioButton GroupName="rdoExchange" Content="Advanced"
IsChecked="{Binding Path=ExchangeDetailsAdvanced, Mode=TwoWay}"
Grid.Column="1"
VerticalContentAlignment="Center"
VerticalAlignment="Center"/>
<Label Grid.Column="0" Grid.Row="1" Grid.RowSpan="2"
Content="Number of Mailbox Profiles:"
VerticalContentAlignment="Center"
Visibility="{Binding Path=IsAdvanced, Mode=TwoWay}" />
</Grid>
这是ViewModel：
public class MainViewModel : ViewModelBase
{
public MainViewModel()
{
}
private bool _isBasicMode = true;
public bool ExchangeDetailsBasic
{
get
{
return this._isBasicMode;
}
set
{
this._isBasicMode = value;
if (value)
{
ExchangeDetailsAdvanced = false;
IsAdvanced = Visibility.Collapsed;
}
this.OnPropertyChanged("ExchangeDetailsBasic");
}
}
private bool _isAdvancedMode = false;
public bool ExchangeDetailsAdvanced
{
get
{
return this._isAdvancedMode;
}
set
{
_isAdvancedMode = value;
if (value)
{
ExchangeDetailsBasic = false;
IsAdvanced = Visibility.Visible;
}
this.OnPropertyChanged("ExchangeDetailsAdvanced");
}
}
private Visibility _isAdvanced = Visibility.Collapsed;
public Visibility IsAdvanced
{
get
{
return _isAdvanced;
}
set
{
_isAdvanced = value;
this.OnPropertyChanged("IsAdvanced");
}
}
}
这是实现INotifyPropertyChanged的基类。
public abstract class ViewModelBase : INotifyPropertyChanged
{
public event PropertyChangedEventHandler PropertyChanged;
protected void OnPropertyChanged(string propertyName)
{
PropertyChangedEventHandler handler = PropertyChanged;
if (handler != null)
{
handler(this, new PropertyChangedEventArgs(propertyName));
}
}
}
答案 2 :(得分：0)
我猜你错过了视图模型类的INotifyPropertyChanged实现。如果您使用了双向数据绑定，并且在选择更改时提升属性更改事件，则一切正常。 @Zamboni用代码示例解释了它。
答案 3 :(得分：0)
这是我的解决方案：一个附加属性，用于切换同一组中所有按钮的IsChecked属性。适用于我的机器： - ）
using System;
using System.Collections.Generic;
using System.Windows;
using System.Windows.Controls;
namespace Elca.MvvmHelpers {
public class RadioButtonHelper : DependencyObject {
private static readonly Dictionary<string, List<RadioButton>> s_group2ButtonsMap = new Dictionary<string, List<RadioButton>>();
private static readonly List<RadioButton> s_knownButtons = new List<RadioButton>();
private static void OnRadioButtonChecked(object sender, RoutedEventArgs e) {
RadioButton rb = (RadioButton)sender;
UncheckOtherButtonsInGroup(rb);
}
public static bool? GetIsChecked(RadioButton d) {
return (bool?) d.GetValue(IsCheckedProperty);
}
public static void SetIsChecked(RadioButton d, bool? value) {
d.SetValue(IsCheckedProperty, value);
}
public static readonly DependencyProperty IsCheckedProperty =
DependencyProperty.RegisterAttached("IsChecked",
typeof(bool?),
typeof(RadioButtonHelper),
new FrameworkPropertyMetadata(false, FrameworkPropertyMetadataOptions.Journal |
FrameworkPropertyMetadataOptions.BindsTwoWayByDefault,
IsCheckedChanged));
public static void IsCheckedChanged(DependencyObject d, DependencyPropertyChangedEventArgs e) {
var rb = d as RadioButton;
if (rb == null) {
throw new Exception("IsChecked attached property only works on a FrameworkElement type");
}
RememberRadioButton(rb);
if ((bool) e.NewValue) {
rb.IsChecked = true; // this triggers OnRadioButtonChecked => other buttons in the same group will be unchecked
}
}
private static void RememberRadioButton(RadioButton rb) {
var groupName = GetGroupName(rb);
// if this button is unknown, add it to the right list, based on its group name
if (s_knownButtons.Contains(rb)) {
return;
}
s_knownButtons.Add(rb);
List<RadioButton> existingButtons;
if (! s_group2ButtonsMap.TryGetValue(groupName, out existingButtons)) {
// unknown group
s_group2ButtonsMap[groupName] = new List<RadioButton> {rb};
RegisterButtonEvents(rb);
} else {
if (! existingButtons.Contains(rb)) {
existingButtons.Add(rb);
RegisterButtonEvents(rb);
}
}
}
private static void RegisterButtonEvents(RadioButton rb) {
rb.Unloaded += OnButtonUnloaded;
rb.Checked += OnRadioButtonChecked;
}
private static void OnButtonUnloaded(object sender, RoutedEventArgs e) {
RadioButton rb = (RadioButton) sender;
ForgetRadioButton(rb);
}
private static void ForgetRadioButton(RadioButton rb) {
List<RadioButton> existingButtons = s_group2ButtonsMap[GetGroupName(rb)];
existingButtons.Remove(rb);
s_knownButtons.Remove(rb);
UnregisterButtonEvents(rb);
}
private static void UnregisterButtonEvents(RadioButton rb) {
rb.Unloaded -= OnButtonUnloaded;
rb.Checked -= OnRadioButtonChecked;
}
private static void UncheckOtherButtonsInGroup(RadioButton rb) {
List<RadioButton> existingButtons = s_group2ButtonsMap[GetGroupName(rb)];
foreach (RadioButton other in existingButtons) {
if (other != rb) {
SetIsChecked(other, false);
}
}
SetIsChecked(rb, true);
}
private static string GetGroupName(RadioButton elt) {
string groupName = elt.GroupName;
if (String.IsNullOrEmpty(groupName)) {
groupName = "none"; // any value will do
}
return groupName;
}
}
}
在视图中，对于每个按钮：
<RadioButton MvvmHelpers:RadioButtonHelper.IsChecked="{Binding IsExplicitFileSelected, Mode=TwoWay}">
...
</RadioButton>
VM为每个单选按钮都有一个布尔属性。必须为每个这样的属性赋值，以启动附加属性的监听过程。
没有组名的所有按钮都被视为属于同一组。