在 MVVM 中获取 BooleanToVisibilityConverter 的 xaml 绑定代码错误

Question

I used progress bar in View as below:

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

• BooleanToVisibilityConverter is defined in ViewModel
• Getting Error on xaml code of view <phone:PhoneApplicationPage.Resources> <BooleanToVisibilityConverter x:Key="BooleanConverter"/> </phone:PhoneApplicationPage.Resources>

*Error is:

The name "BooleanToVisibilityConverter" does not exist in the namespace " http://schemas.microsoft.com/client/2007 ".

Please Tell me how to resolve this error

Answer 1

You can define a converter like this :

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();
        }
    }
}

Build your solution ! And in 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 2

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

Answer 3

You'll need define your namespace in xaml. At the top level of your Window/UserControl, you need to define an xml namespace:

xmlns:yn="clr-namespace:YourNamespace"

and then you need to refer to your BooleanToVisibilityConverter using that namespace:

<yn:BooleanToVisibilityConverter ... />