上XAML在MVVM

Question

綁定代碼爲BooleanToVisibilityConverter獲取錯誤我在視圖中使用進度條如下：

<ProgressBar IsIndeterminate="{Binding IsBusy}" Visibility="{Binding IsBusy,Converter={StaticResource BooleanToVisibilityConverter}}" HorizontalAlignment="Left" Height="33" Margin="46,222,0,0" VerticalAlignment="Top" Width="358"/> 

• BooleanToVisibilityConverter在視圖模型
• 定義獲取有關的視圖XAML代碼錯誤 <phone:PhoneApplicationPage.Resources> <BooleanToVisibilityConverter x:Key="BooleanConverter"/> </phone:PhoneApplicationPage.Resources>

*錯誤是：

命名空間「http://schemas.microsoft.com/client/2007」中不存在名稱「BooleanToVisibilityConverter」。

請告訴我如何解決此錯誤

Answer 1

您需要在xaml中定義您的名稱空間。在你的窗口/用戶控件的頂層，您需要定義XML命名空間：

xmlns:yn="clr-namespace:YourNamespace" 

，然後你需要使用該命名空間來引用你BooleanToVisibilityConverter：

<yn:BooleanToVisibilityConverter ... /> 

Answer 2

您可以定義一個轉換器像這樣：

namespace YourNamespace 
{ 
    public class BooleanToVisibilityConverter : IValueConverter 
    { 

     public object Convert(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture) 
     { 
      return (bool)value ? Visibility.Visible : Visibility.Collapsed; 
     } 

     public object ConvertBack(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture) 
     { 
      throw new NotImplementedException(); 
     } 
    } 
} 

構建您的解決方案！ 而在XAML：

<navigation:Page x:Class="MyCustomNamespace" 
    xmlns:converters="clr-namespace:YourNamespace"> 
    <navigation:Page.Resources> 
     <converters:BooleanToVisibilityConverter x:Key="BooleanToVisibility" /> 
    </navigation:Page.Resources> 
    <TextBlock Visibility="{Binding BooleanFromViewModel, Convert={StaticResource BooleanToVisibility}" /> 
</navigation:Page> 

Answer 3

<UserControl xmlns:converter="your namespace"> 
<UserControl.Resources> 
<converter:BooleanToVisibilityConverter x:Key="bool2VisibilityConverter" /> 
</UserControl.Resources> 
<TextBlock Visibility={Binding Path=Field, Converter={StaticResource bool2VisibilityConverter}} /> 
</UserControl>