Question

我重写了这个问题，以更详细地说明重用xaml定义的含义。

<UserControl x:Class="XamlDemo.ControlA"
             xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
             xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
             xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" 
             xmlns:d="http://schemas.microsoft.com/expression/blend/2008" 
             xmlns:local="clr-namespace:XamlDemo"
             xmlns:foo="clr-namespace:XamlDemo.Foo"
             xmlns:bar="clr-namespace:XamlDemo.Bar"
             mc:Ignorable="d">
<!--
    xmlns:foo="clr-namespace:XamlDemo.Foo"
    xmlns:bar="clr-namespace:XamlDemo.Bar"
    foo and bar will tend to repeat in exactly this constellation all over the project.
    If one of these namespaces changes all xaml files need to be edited.
    I would like to include a different file as a component where i would only write foo and bar once
-->
    <StackPanel>
        <foo:ExtTextBlock></foo:ExtTextBlock>
        <bar:ExtLabel></bar:ExtLabel>
    </StackPanel>
</UserControl>


<UserControl x:Class="XamlDemo.ControlB"
             xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
             xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
             xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" 
             xmlns:d="http://schemas.microsoft.com/expression/blend/2008" 
             xmlns:local="clr-namespace:XamlDemo"
             xmlns:foo="clr-namespace:XamlDemo.Foo"
             xmlns:bar="clr-namespace:XamlDemo.Bar"
             mc:Ignorable="d" >
    <StackPanel>
        <foo:ExtTextBox></foo:ExtTextBox>
        <bar:ExtButton></bar:ExtButton>
    </StackPanel>
</UserControl>

带

using System.Windows.Controls;

namespace XamlDemo.Bar
{
    public class ExtButton : Button { }
    public class ExtLabel : Label { }
}
namespace XamlDemo.Foo
{
    public class ExtTextBlock : TextBlock { }
    public class ExtTextBox : TextBox { }
}

两者都使用我的本地命名空间声明。我希望他们包含对不同xaml的引用，并从那里获取名称空间

我没有找到任何办法 - 这里有一些概念代码说明了我的想象。显然这不会编译。

<magic
             xmlns:foo="clr-namespace:XamlDemo.Foo"
             xmlns:bar="clr-namespace:XamlDemo.Bar">
</magic>

<UserControl x:Class="..."
             xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
             xmlns="get it from magic">
</UserControl>

Answer 1

基础控制：

namespace WpfApplication9
{
    public class BaseControl : UserControl
    {
        public BaseControl()
        {

        }
    public override void EndInit()
    {
        base.EndInit();
        ExtTextBlock block = new ExtTextBlock { Width = 100 , Height = 20 , Text = "Test Block" };
        ExtButton button = new ExtButton { Width = 100, Height = 20 , Content = "ClickMe"};
        ExtLabel label = new ExtLabel { Width = 100, Height = 30 ,Content = "Test Label"};
        ExtTextBox txtBox = new ExtTextBox { Width = 100, Height = 20 ,Text= "Hi There"};
        Grid g = (Grid)BaseControl.FindChild(this, "gridMain");
        g.Children.Add(button);
        g.Children.Add(block);
        g.Children.Add(label);
        g.Children.Add(txtBox);
        Grid.SetRow(block, 0);
        Grid.SetRow(button, 1);
        Grid.SetRow(label, 2);
        Grid.SetRow(txtBox, 3);

        button.Click += button_Click;
    }

    void button_Click(object sender, RoutedEventArgs e)
    {
        MessageBox.Show("Hi There");
    }

    public static DependencyObject FindChild(DependencyObject parent, string name)
    {
        // confirm parent and name are valid.
        if (parent == null || string.IsNullOrEmpty(name)) return null;

        if (parent is FrameworkElement && (parent as FrameworkElement).Name == name) return parent;

        DependencyObject result = null;

        if (parent is FrameworkElement) (parent as FrameworkElement).ApplyTemplate();

        int childrenCount = VisualTreeHelper.GetChildrenCount(parent);
        for (int i = 0; i < childrenCount; i++)
        {
            var child = VisualTreeHelper.GetChild(parent, i);
            result = FindChild(child, name);
            if (result != null) break;
        }

        return result;
    }

    /// <summary>
    /// Looks for a child control within a parent by type
    /// </summary>
    public static T FindChild<T>(DependencyObject parent)
        where T : DependencyObject
    {
        // confirm parent is valid.
        if (parent == null) return null;
        if (parent is T) return parent as T;

        DependencyObject foundChild = null;

        if (parent is FrameworkElement) (parent as FrameworkElement).ApplyTemplate();

        int childrenCount = VisualTreeHelper.GetChildrenCount(parent);
        for (int i = 0; i < childrenCount; i++)
        {
            var child = VisualTreeHelper.GetChild(parent, i);
            foundChild = FindChild<T>(child);
            if (foundChild != null) break;
        }

        return foundChild as T;
    }
}
}

namespace WpfApplication9.Foo
{
    public class ExtTextBlock : TextBlock { }
    public class ExtTextBox : TextBox { }
}

namespace WpfApplication9.Bar
{
    public class ExtButton : Button { }
    public class ExtLabel : Label { }
}

控制1. xaml

<base:BaseControl x:Class="WpfApplication9.Control1"
         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
         xmlns:base="clr-namespace:WpfApplication9"
         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" 
         xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
         mc:Ignorable="d" 
         d:DesignHeight="300" d:DesignWidth="300">
<Grid x:Name="gridMain">
    <Grid.RowDefinitions>
        <RowDefinition Height="1*"/>
        <RowDefinition Height="1*"/>
        <RowDefinition Height="1*"/>
        <RowDefinition Height="1*"/>
    </Grid.RowDefinitions>
</Grid>

您可以在创建Control1时创建Control2类。正如我所说，xaml无法实现。

Answer 2

正如Freeman所述，XAML继承是不可能的。无论如何，您可以考虑使用XmlnsDefinitionAttribute来减少和清除命名空间定义。

您可以在CodeProject上找到一篇有趣的文章here。

如果要在XAML 中包含的名称空间位于参考程序集中，您可以轻松地将它们映射到单个URI中。只需以这种方式在引用的程序集中添加XmlnsDefinition属性：

[assembly: XmlnsDefinition("urn:johannes-ui-controls", "XamlDemo.Foo")]
[assembly: XmlnsDefinition("urn:johannes-ui-controls", "XamlDemo.Bar")]

等等。

然后在您的XAML中，您可以这样使用它们：

<UserControl x:Class="..."
             xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
             xmlns:uiControls="urn:johannes-ui-controls">
    <StackPanel>
        <uiControls:ExtTextBox />
        <uiControls:ExtButton />
    </StackPanel>
</UserControl>

此解决方案的限制是您不能将XmlnsDefinition属性与包含XAML的程序集一起使用。可能这不是你的意思，但也许它可以帮助你。

如何在项目中重用xaml命名空间定义

2 个答案: