我怎样才能绑定前景在我的ViewModel的属性？ [英] How can I bind Foreground to a property in my ViewModel?
问题描述
我想TextBlock的前景属性绑定到我的视图模型一个属性。
I would like to bind the foreground property of a TextBlock to a Property in my ViewModel.
这不工作：
修改
查看：
TextBlock
Text="{Binding Path=FullName, Mode=OneWay}"
Foreground="{Binding Path=ForegroundColor}"
Margin="0 5 3 5"
后面的代码：
CustomerHeaderViewModel customerHeaderViewModel = new CustomerHeaderViewModel();
customerHeaderViewModel.LoadCustomers();
CustomerHeaderView.DataContext = customerHeaderViewModel;
查看产品型号：
private System.Windows.Media.Brush _foregroundColor;
_foregroundColor = System.Windows.Media.Brushes.DarkSeaGreen;
public System.Windows.Media.Brush ForegroundColor
{
get { return _foregroundColor; }
set { _foregroundColor = value;
OnPropertyChanged("ForegroundColor");
}
}
public CustomerHeaderViewModel()
{
ForegroundColor = System.Windows.Media.Brushes.Red;
}
所有其他属性（文本等）正确绑定。
All other properties (Text etc) correctly bind.
我在做什么错
推荐答案
检查您的解决方案是这样的：
查看：
Check if your solution is like that: View:
<Window x:Class="WpfApplication13.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:vm="clr-namespace:WpfApplication13"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
Title="MainWindow" Height="350" Width="525">
<Window.DataContext>
<vm:MainVM/>
</Window.DataContext>
<Grid>
<TextBlock Text="{Binding Path=FullName, Mode=OneWay}"
Foreground="{Binding Path=ForegroundColor}"
Margin="0 5 3 5"/>
</Grid>
</Window>
视图模型：
ViewModel:
public class MainVM : INotifyPropertyChanged
{
protected void OnPropertyChanged(string porpName)
{
var temp = PropertyChanged;
if (temp != null)
temp(this, new PropertyChangedEventArgs(porpName));
}
public event PropertyChangedEventHandler PropertyChanged;
private System.Windows.Media.Brush _foregroundColor = System.Windows.Media.Brushes.DarkSeaGreen;
public string FullName
{
get
{
return "Hello world";
}
}
public System.Windows.Media.Brush ForegroundColor
{
get { return _foregroundColor; }
set
{
_foregroundColor = value;
OnPropertyChanged("ForegroundColor");
}
}
}
和记住，如果你想设置为ForegroundColor新的价值VM你sholud做这样的：
and remember that if you want to set new value for ForegroundColor in VM you sholud do it like that:
ForegroundColor = System.Windows.Media.Brushes.Red;
要提高PropertyChangedEvent
to raise PropertyChangedEvent
Accordind新关于您的问题的信息，你可以试试这个解决方法：
Accordind to new information about your problem, you could try this solution:
CustomerHeaderViewModel.cs
CustomerHeaderViewModel.cs
class CustomerHeaderViewModel : INotifyPropertyChanged
{
public ObservableCollection<Customer> Customers { get; set; }
public void LoadCustomers()
{
ObservableCollection<Customer> customers = new ObservableCollection<Customer>();
//this is where you would actually call your service
customers.Add(new Customer { FirstName = "Jim", LastName = "Smith", NumberOfContracts = 23 });
customers.Add(new Customer { FirstName = "Jane", LastName = "Smith", NumberOfContracts = 22 });
customers.Add(new Customer { FirstName = "John", LastName = "Tester", NumberOfContracts = 33 });
customers.Add(new Customer { FirstName = "Robert", LastName = "Smith", NumberOfContracts = 2 });
customers.Add(new Customer { FirstName = "Hank", LastName = "Jobs", NumberOfContracts = 5 });
Customers = customers;
}
protected void OnPropertyChanged(string porpName)
{
var temp = PropertyChanged;
if (temp != null)
temp(this, new PropertyChangedEventArgs(porpName));
}
public event PropertyChangedEventHandler PropertyChanged;
private System.Windows.Media.Brush _foregroundColor = System.Windows.Media.Brushes.DarkSeaGreen;
public System.Windows.Media.Brush ForegroundColor
{
get { return _foregroundColor; }
set
{
_foregroundColor = value;
OnPropertyChanged("ForegroundColor");
}
}
}
CustomerHeaderView.xaml
CustomerHeaderView.xaml
<UserControl x:Class="TestMvvm444.Views.CustomerHeaderView"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
x:Name="main">
<Grid>
<StackPanel HorizontalAlignment="Left">
<ItemsControl ItemsSource="{Binding Path=Customers}">
<ItemsControl.ItemTemplate>
<DataTemplate>
<StackPanel Orientation="Horizontal">
<StackPanel Orientation="Horizontal">
<TextBox
Text="{Binding Path=FirstName, Mode=TwoWay}"
Width="100"
Margin="3 5 3 5"/>
<TextBox
Text="{Binding Path=LastName, Mode=TwoWay}"
Width="100"
Margin="0 5 3 5"/>
<TextBlock
Text="{Binding Path=FullName, Mode=OneWay}"
Foreground="{Binding ElementName=main, Path=DataContext.ForegroundColor}"
Margin="0 5 3 5"/>
</StackPanel>
</StackPanel>
</DataTemplate>
</ItemsControl.ItemTemplate>
</ItemsControl>
</StackPanel>
</Grid>
</UserControl>
在把ForegroundColor属性驻留在CustomerHeaderViewModel.cs所以它是所有客户的价值呈现的场景。在CustomerHeaderView.xaml我加X：为命名用户控件有一个方法可行引用这个元素来DataContext的。如果你不希望使用X：名称为用户控件，你可以试试这个：
In presented scenario the ForegroundColor property resides in CustomerHeaderViewModel.cs so it is value for all customers. In CustomerHeaderView.xaml I added x:Name for UserControl to have a possiblity to refer to DataContext of this element. If you don't want to use x:Name for UserControl, you can try this:
<TextBlock
Text="{Binding Path=FullName, Mode=OneWay}"
Foreground="{Binding RelativeSource={RelativeSource FindAncestor,
AncestorType={x:Type UserControl}}, Path=DataContext.ForegroundColor}"
Margin="0 5 3 5"/>
记住，这种控制的DataContext在MainWindow.cs先前设置。
Remember that DataContext of this control was set earlier in MainWindow.cs.
MainWindow.cs
MainWindow.cs
public partial class Window1 : Window
{
public Window1()
{
InitializeComponent();
}
private void Window_Loaded(object sender, RoutedEventArgs e)
{
CustomerHeaderViewModel customerHeaderViewModel = new CustomerHeaderViewModel();
customerHeaderViewModel.LoadCustomers();
CustomerHeaderView.DataContext = customerHeaderViewModel;
}
}
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