我有一个组合框,显示了一个项目列表。显示的项目列表由一组单选按钮确定。我附加单击按钮单击事件并尝试在组合框上设置新的项目源。我希望selectedItem默认为0,而不是-1。
我做错了什么?
<Grid>
<ComboBox Name="cb_Test" />
<RadioButton Content="List 1" Name="radioButton1" Click="radioButton1_Click" />
<RadioButton Content="List 2" Name="radioButton2" Click="radioButton2_Click" />
</Grid>
public partial class MainWindow : Window
{
List<string> list1 = new List<string>() { "list 1", "list 1", "list 1" };
List<string> list2 = new List<string>() { "list 2", "list 2", "list 2" };
ComboBoxViewModel viewModel = new ComboBoxViewModel();
public MainWindow()
{
InitializeComponent();
this.DataContext = viewModel;
cb_Test.ItemsSource = list1;
}
private void radioButton1_Click(object sender, RoutedEventArgs e)
{
cb_Test.ItemsSource = list1;
viewModel.SelectedIndex = 0;
}
private void radioButton2_Click(object sender, RoutedEventArgs e)
{
cb_Test.ItemsSource = list2;
viewModel.SelectedIndex = 0;
}
}
public class ComboBoxViewModel : INotifyPropertyChanged
{
private int selectedIndex;
public event PropertyChangedEventHandler PropertyChanged;
public int SelectedIndex
{
get { return selectedIndex; }
set
{
if (selectedIndex != value)
{
selectedIndex = value;
NotifyPropertyChanged("SelectedIndex");
}
}
}
private void NotifyPropertyChanged(string controlName)
{
if (PropertyChanged != null)
{
PropertyChanged(this, new PropertyChangedEventArgs(controlName));
}
}
}
答案 0 :(得分:1)
您的XAML中没有任何与ComboBoxViewModel
视图模型的数据绑定,至少提供了一个。我认为这就是问题。
答案 1 :(得分:0)
您需要将组合框绑定到VM。
public partial class MainWindow : Window
{
List<string> list1 = new List<string>() { "list 1", "list 1", "list 1" };
List<string> list2 = new List<string>() { "list 2", "list 2", "list 2" };
ComboBoxViewModel viewModel = new ComboBoxViewModel();
public MainWindow()
{
InitializeComponent();
cb_Test.DataContext = viewModel;
}
private void radioButton1_Click(object sender, RoutedEventArgs e)
{
viewModel.ItemsSource = list1;
viewModel.SelectedIndex = 0;
}
private void radioButton2_Click(object sender, RoutedEventArgs e)
{
viewModel.ItemsSource = list2;
viewModel.SelectedIndex = 0;
}
}
和XAML
<Grid>
<ComboBox Name="cb_Test"
ItemsSource="{Binding ItemsSourse}"
SelectedIndex="{Binding SelectedIndex}"/>
<RadioButton Content="List 1" Name="radioButton1" Click="radioButton1_Click" />
<RadioButton Content="List 2" Name="radioButton2" Click="radioButton2_Click" />
</Grid>
更好的设计是将代码viewModel.ItemsSource = list1; viewModel.SelectedIndex = 0;
移动到VM本身。
答案 2 :(得分:0)
同意Tigran。您需要将ComboBoxViewModel指定为Window / Page / Control的DataContext,无论这是什么,您需要在xaml中的ComboBox声明中绑定SelectedIndex。由于您需要绑定,您还应该使用SelectedIndex将List集合移动到一个ViewModel,并将ComboBox ItemsSource绑定到您可以在特定条件下设置的ViewModel中的Property。