如何在 XAML 中创建动态接口

Question

如果有人知道使用数据相关 (DataContext="{Binding User}") 或静态数据 (DataContext="{Binding User, Source={StaticResource Locator}}") 创建动态 xaml 的解决方案？

这样的解决方案可以保存在控件隐藏和附加字段（Visibility="{Binding IsAnonim, Converter={StaticResource VisibilityConverter}}"）上。而且 XAML 必须只满足这种情况下需要的内容，并且不会充满不必要的控件。

可以在渲染时刻执行的代码（“if (IsUser) { }”）。

下面的例子：

    <UserControl
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
        xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
        d:DesignHeight="300" d:DesignWidth="400">
        <Grid x:Name="LayoutRoot" DataContext="{Binding User}">
            <StackPanel>
<? if (IsUser) { ?>
   <TextBox Text="{Binding UserName, Mode=TwoWay}" />
   <PasswordBox Text="{Binding UserPass, Mode=TwoWay}" />
<? } else if (IsAnonim) { ?>
   <TextBox Text="{Binding AnonimName, Mode=TwoWay}" />
<? } ?>
                <TextBox Text="{Binding MsgText, Mode=TwoWay}" />
                <Button Content="Button" Command="{Binding PostCommand}" />        
            </StackPanel>
        </Grid> </UserControl>

附：其他解决方案是可能的。谢谢。

Answer 1

绑定和可见性很简单

<UserControl
   xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
   xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
   xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
   xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
   d:DesignHeight="300" d:DesignWidth="400">
   <UserControl.Resources>
     <Convertors:BooleanToInvisibiltyConverterx:Key="booleanToInvisibiltyConverter"/>
     <BooleanToVisibiltyConverterx:Key="booleanToVisibiltyConverter"/>
   </UserControl.Resources>

   <Grid x:Name="LayoutRoot" DataContext="{Binding User}">
     <StackPanel>
       <StackPanel Visibility="{Binding IsUser, Converter={StaticResource booleanToVisibiltyConverter}}">
         <TextBox Text="{Binding UserName, Mode=TwoWay}" />
         <PasswordBox Text="{Binding UserPass, Mode=TwoWay}" />
      </StackPanel>
      <StackPanel Visibility="{Binding IsUser, Converter={StaticResource booleanToInvisibiltyConverter}}">
        <TextBox Text="{Binding AnonimName, Mode=TwoWay}" />
      </StackPanel
      <TextBox Text="{Binding MsgText, Mode=TwoWay}" />
      <Button Content="Button" Command="{Binding PostCommand}" />        
    </StackPanel>
  </Grid>
</UserControl>

您只需要定义资源并创建一个 InvisibiltyConverter

/// <summary>The boolean to invisibility converter.</summary>
public class BooleanToInvisibilityConverter : IValueConverter
{
    /// <summary>The convert.</summary>
    /// <param name="value">The value.</param>
    /// <param name="targetType">The target type.</param>
    /// <param name="parameter">The parameter.</param>
    /// <param name="culture">The culture.</param>
    /// <returns>The <see cref="object"/>.</returns>
    public object Convert(object value, Type targetType, object parameter, CultureInfo culture)
    {
        if (value != null 
            && (bool)value == true)
        {
            return Visibility.Collapsed;
        }

        return Visibility.Visible;
    }

    /// <summary>The convert back.</summary>
    /// <param name="value">The value.</param>
    /// <param name="targetType">The target type.</param>
    /// <param name="parameter">The parameter.</param>
    /// <param name="culture">The culture.</param>
    /// <returns>The <see cref="object"/>.</returns>
    public object ConvertBack(object value, Type targetType, object parameter, CultureInfo culture)
    {
        throw new NotImplementedException();
    }
}

但是随着复杂性的增加，您会发现将所有 UI 保存在单个 xaml 文件中变得不可能。那时，您需要按照 cmets 中的 @Clemens 建议了解数据模板。见Data templating overview