带有通用代码隐藏的WPF UserControl

Question

我有这个代码:

CustomUserControl.xaml.cs

namespace MyProject
{
    public partial class CustomUserControl<T> : UserControl
    {
        ...
    }
}

而这个xaml:

CustomUserControl.xaml

<UserControl x:Class="MyProject.CustomUserControl"
         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
         xmlns:sys="clr-namespace:System;assembly=mscorlib">
<Grid>

</Grid>

它不起作用,因为x:Class ="MyProject.CustomUserControl"与代码隐藏的泛型类定义不匹配.有没有办法使这项工作？

Answer 1

您可以在没有XAML文件的情况下创建通用的"代码隐藏"文件:

public class CustomUserControl<T>: UserControl
{ }

而不是从它提供特定的类作为参数:

public partial class SpecificUserControl : CustomUserControl<Presenter>
{
    public SpecificUserControl()
    {
        InitializeComponent();
    }
}

XAML:

<application:CustomUserControl 
     x:TypeArguments="application:Presenter"
     xmlns:application="clr-namespace:YourApplicationNamespace"
...

不幸的是,在Visual Studio 2012 Update 2之前,Visual Studio设计器似乎不支持此类泛型(请参阅/sf/answers/1057708081/)

Answer 2

到目前为止，在其他任何地方都找不到我的解决方案。主要区别在于，对于通用用户控件类，我只有一个.xaml文件，而对于每个实际用户控件却没有一个。

GenericUserControl.xaml.cs

using System.Windows.Controls;

namespace TestGenericUserControl
{
    public abstract partial class GenericUserControl : UserControl
    {
        // If you use event handlers in GenericUserControl.xaml, you have to define 
        // them here as abstract and implement them in the generic class below, e.g.:

        // abstract protected void MouseClick(object sender, MouseButtonEventArgs e);
    }

    public class GenericUserControl<T> : GenericUserControl
    {
        // generic properties and stuff

        public GenericUserControl()
        {
            InitializeComponent();
        }
    }

    // To use the GenericUserControl<T> in XAML, you could define:
    public class GenericUserControlString : GenericUserControl<string> { }
    // and use it in XAML, e.g.:
    // <GenericUserControlString />
    // alternatively you could probably (not sure) define a markup extension to instantiate
    // it directly in XAML
}

GenericUserControl.xaml

<UserControl x:Class="TestGenericUserControl.GenericUserControl"
        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" 
        mc:Ignorable="d">
    <Grid>
        <Label Content="hello" />
    </Grid>
</UserControl>

Answer 3

不幸的是，XAML 不支持背后的通用代码，您可以绕过这个。

请参阅以下链接：

http://forums.silverlight.net/forums/p/29051/197576.aspx

我可以在 XAML（.NET 4 Framework 之前的版本）中指定泛型类型吗？

未来版本的 Visual Studuo 可能会通过 XAML 2009 原生支持通用控件。