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[英]Is it possible to bind the property of a datacontext to the property of another datacontext
[英]In WPF is it possible to bind to a property of a property in my DataContext?
我需要將TextBox的Text綁定到本身是DataContext屬性的類的屬性。 因此,例如,如果我有一個名為ServerInstance的類,並且它有一個名為Name的字符串屬性。 我在后面的代碼中公開了一個ServerInstance作為名為SelectedInstance的屬性(在這種情況下為viewmodel)。 我的問題是如何將TextBox綁定到SelectedInstance屬性的Name屬性?
這是我的ViewModel /代碼背后:
public class ViewModel : Notifier
{
private MobileServerInstance m_instance = null;
private RelayCommand m_addCommand = null;
private RelayCommand m_clearCommand = null;
public MobileServerInstance ServerInstance
{
get { return m_instance; }
set { m_instance = value; OnPropertyChanged("ServerInstance"); }
}
public ICommand AddCommand
{
get
{
if (m_addCommand == null)
{
m_addCommand = new RelayCommand(parameter=>Add(parameter), parameter=>CanAdd(parameter));
}
return m_addCommand;
}
}
public ICommand ClearCommand
{
get
{
if (m_clearCommand == null)
{
m_clearCommand = new RelayCommand(parameter => Clear(parameter), parameter => CanClear(parameter));
}
return m_clearCommand;
}
}
private bool CanClear(object parameter)
{
return m_instance != null;
}
private void Clear(object parameter)
{
m_instance = null;
}
private bool CanAdd(object parameter)
{
return m_instance == null;
}
private void Add(object parameter)
{
m_instance = new MobileServerInstance();
}
}
Notifier是一個基類,它實現INotifyPropertyChanged接口,並提供一個受保護的OnPropertyChanged方法,該方法引發PropertyChange事件-那里的典型模式。
這是我用於DataContext的簡單類:
public class MobileServerInstance : Notifier
{
private string m_name = "Name";
private string m_alias = "Alias";
public string Name
{
get { return m_name; }
set { m_name = value; OnPropertyChanged("Name"); }
}
public string Alias
{
get { return m_alias; }
set { m_alias = value; OnPropertyChanged("Alias"); }
}
}
最后是我的xaml(這是一個POC,因此UI非常簡單):
<Window x:Class="WpfApplication4.Window1"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:src="clr-namespace:WpfApplication4"
Title="Window1" Height="300" Width="500">
<Window.DataContext>
<src:ViewModel />
</Window.DataContext>
<StackPanel>
<StackPanel Orientation="Horizontal">
<Label Content="Name:" Margin="0 0 2 0" />
<ComboBox Margin="0 0 8 0" Width="125" />
<Button Margin="0 0 4 0" Content="Add" Command="{Binding AddCommand}" Width="75" />
<Button Content="Clear" Command="{Binding ClearCommand}" Width="75" />
</StackPanel>
<StackPanel Margin="20 5 20 5"">
<StackPanel Orientation="Horizontal">
<Label Width="40" Content="Name:" Margin="0 0 2 0" />
<TextBox Width="250" Text="{Binding ServerInstance.Name}" />
</StackPanel>
<StackPanel Orientation="Horizontal" Margin="0 5 0 0">
<Label Width="40" Content="Alias:" Margin="0 0 2 0" />
<TextBox Width="250" Text="{Binding ServerInstance.Alias}" />
</StackPanel>
</StackPanel>
</StackPanel>
</Window>
預先感謝您提供的任何幫助。
{Binding Path=ServerInstance.Name}
必須起作用,當然,即使ServerInstance應該是INotifyPropertyChanged
也要看到名稱更改值。
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