4
我在更改整數字段時更新簡單數據綁定標籤時遇到問題。我實現了INotifyPropertChanged，當我改變我的變量值時，這個事件被觸發。用戶界面不會更新，標籤也不會更改。過去我沒有做過太多的數據綁定，所以我可能錯過了一些東西，但我還沒有找到它。XAML數據綁定在屬性更改時不更新UI
這裏是我有我的XAML：
<Window x:Class="TestBinding.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:mc="http://schemas.openxmlformats.org/markup-
compatibility/2006"
xmlns:local="clr-namespace:TestBinding"
mc:Ignorable="d"
Title="MainWindow" Height="350" Width="525">
<StackPanel>
<Button Command="{Binding TestCommand, Mode=OneWay}" >
<Button.DataContext>
<local:TestVM/>
</Button.DataContext> Add 1</Button>
<Label Content="{Binding Count,
Mode=OneWay,UpdateSourceTrigger=PropertyChanged}">
<Label.DataContext>
<local:TestVM/>
</Label.DataContext>
</Label>
</StackPanel>
</Window>
這裏是我的視圖模型C＃：
class TestVM : INotifyPropertyChanged
{
private int _count;
private RelayCommand _testCommand;
public TestVM()
{
Count=0;
}
public int Count
{
get { return _count; }
set { _count = value; OnPropertyChanged(); }
}
public void Test()
{
Count++;
}
public ICommand TestCommand
{
get
{
if (_testCommand == null)
{
_testCommand = new RelayCommand(param => this.Test(), param => true);
}
return _testCommand;
}
}
public event PropertyChangedEventHandler PropertyChanged;
protected void OnPropertyChanged([System.Runtime.CompilerServices.CallerMemberName] string propertyName = "")
{
if (this.PropertyChanged != null)
{
Console.WriteLine(propertyName);
var e = new PropertyChangedEventArgs(propertyName);
this.PropertyChanged(this, e);
}
}
}
這裏是我的ICommand C＃（如果你需要它來複制我有什麼）：
public class RelayCommand : ICommand
{
#region Fields
readonly Action<object> _execute;
readonly Predicate<object> _canExecute;
#endregion // Fields
#region Constructors
public RelayCommand(Action<object> execute) : this(execute, null) { }
public RelayCommand(Action<object> execute, Predicate<object> canExecute)
{
if (execute == null) throw new ArgumentNullException("execute");
_execute = execute;
_canExecute = canExecute;
}
#endregion // Constructors
#region ICommand Members [DebuggerStepThrough]
public bool CanExecute(object parameter)
{
return _canExecute == null ? true : _canExecute(parameter);
}
public event EventHandler CanExecuteChanged
{
add { CommandManager.RequerySuggested += value; }
remove { CommandManager.RequerySuggested -= value; }
}
public void Execute(object parameter)
{
_execute(parameter);
}
#endregion
// ICommand Members
}
任何和所有的幫助，非常感謝。
編輯： 我更新了我的xaml toadflakz建議和它的工作。
<Window x:Class="TestBinding.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
xmlns:local="clr-namespace:TestBinding"
mc:Ignorable="d"
Title="MainWindow" Height="350" Width="525">
<Window.DataContext>
<local:TestVM/>
</Window.DataContext>
<StackPanel>
<Button Command="{Binding TestCommand, Mode=OneWay}" >Add 1</Button>
<Label Content="{Binding Count, Mode=OneWay,UpdateSourceTrigger=PropertyChanged}" />
</StackPanel>
</Window>