【发布时间】：2015-02-25 02:32:16
【问题描述】：
我是 MVVM 的新手，在这个小应用程序中，我有一个列表框、三个文本框和两个按钮，一个是更新，另一个是添加。在 XAML 中，我已经完成了所有列表框列与文本框的绑定，根据命令，当我更改任一文本框中的值时，我的更新按钮功能正常，但我不知道如何从文本框中获取值并使用命令在集合中添加值。
这是 Xaml 代码。
<Grid Height="314">
<Grid.RowDefinitions>
<RowDefinition Height="Auto"/>
<RowDefinition Height="*"/>
<RowDefinition Height="Auto"/>
</Grid.RowDefinitions>
<ListView Name="ListViewEmployeeDetails" Grid.Row="1" Margin="4,109,12,23" ItemsSource="{Binding Products}" >
<ListView.View>
<GridView x:Name="grdTest">
<GridViewColumn Header="ID" DisplayMemberBinding="{Binding ID}" Width="100"/>
<GridViewColumn Header="Name" DisplayMemberBinding="{Binding Name}" Width="100" />
<GridViewColumn Header="Price" DisplayMemberBinding="{Binding Price}" Width="100" />
</GridView>
</ListView.View>
</ListView>
<TextBox Grid.Row="1" Height="23" HorizontalAlignment="Left" Margin="80,7,0,0" Name="txtID" VerticalAlignment="Top" Width="178" Text="{Binding ElementName=ListViewEmployeeDetails,Path=SelectedItem.ID}" />
<TextBox Grid.Row="1" Height="23" HorizontalAlignment="Left" Margin="80,35,0,0" Name="txtName" VerticalAlignment="Top" Width="178" Text="{Binding ElementName=ListViewEmployeeDetails,Path=SelectedItem.Name}" />
<TextBox Grid.Row="1" Height="23" HorizontalAlignment="Left" Margin="80,61,0,0" Name="txtPrice" VerticalAlignment="Top" Width="178" Text="{Binding ElementName=ListViewEmployeeDetails,Path=SelectedItem.Price}" />
<Label Content="ID" Grid.Row="1" HorizontalAlignment="Left" Margin="12,12,0,274" Name="label1" />
<Label Content="Price" Grid.Row="1" Height="28" HorizontalAlignment="Left" Margin="12,59,0,0" Name="label2" VerticalAlignment="Top" />
<Label Content="Name" Grid.Row="1" Height="28" HorizontalAlignment="Left" Margin="12,35,0,0" Name="label3" VerticalAlignment="Top" />
<Button Content="Update" Grid.Row="1" Height="23" HorizontalAlignment="Left" Margin="311,59,0,0" Name="btnUpdate"
VerticalAlignment="Top" Width="141"
Command="{Binding Path=UpdateCommad}"
/>
<Button Content="Add" Grid.Row="1" Height="23" HorizontalAlignment="Left" Margin="311,17,0,0" Name="btnAdd"
VerticalAlignment="Top" Width="141"
Command="{Binding UpdateCommad}"
/>
</Grid>
这是产品类
public class Product : INotifyPropertyChanged
{
private int m_ID;
private string m_Name;
private double m_Price;
#region INotifyPropertyChanged Members
public event PropertyChangedEventHandler PropertyChanged;
private void OnPropertyChanged(string propertyName)
{
if (PropertyChanged != null)
{
PropertyChanged(this, new PropertyChangedEventArgs(propertyName));
}
}
#endregion
public int ID
{
get
{
return m_ID;
}
set
{
m_ID = value;
OnPropertyChanged("ID");
}
}
public string Name
{
get
{
return m_Name;
}
set
{
m_Name = value;
OnPropertyChanged("Name");
}
}
public double Price
{
get
{
return m_Price;
}
set
{
m_Price = value;
OnPropertyChanged("Price");
}
}
}
这里是 ViewModel 类，现在我将产品静态添加到 m_Products 中。
class ProductViewModel
{
private ObservableCollection<Product> m_Products;
public ProductViewModel()
{
m_Products = new ObservableCollection<Product>
{
new Product {ID=1, Name ="Pro1", Price=10},
new Product{ID=2, Name="BAse2", Price=12}
};
}
public ObservableCollection<Product> Products
{
get
{
return m_Products;
}
set
{
m_Products = value;
}
}
private ICommand mUpdater;
public ICommand UpdateCommand
{
get
{
if (mUpdater == null)
mUpdater = new Updater();
return mUpdater;
}
set
{
mUpdater = value;
}
}
private ICommand addUpdater;
public ICommand AddCommand
{
get
{
if (addUpdater == null)
addUpdater = new Updater();
return addUpdater;
}
set
{
addUpdater = value;
}
}
private class Updater : ICommand
{
#region ICommand Members
public bool CanExecute(object parameter)
{
return true;
}
public event EventHandler CanExecuteChanged;
public void Execute(object parameter)
{
}
#endregion
}
}
现在我不知道如何通过单击添加按钮上的命令将值（产品）添加到集合中。
【问题讨论】：
-
在 ListBox 中，当我添加新条目时，它将使用新条目更新所有可用条目。我正在使用 Observable Collection，这是一个问题吗？