WPF中如何继承一个UserControl
有个场景， 自定义了一个控件BaseControl， 它从UserControl继承的。由于业务需求， 公开了一个protected virtual void Process() 函数。 在不同的场景下可以继承BaseControl并重新Process（）方法，从而实现不同的逻辑。
BaseControl的cs如下：
public partial class BaseControl : UserControl
｛
public BaseControl（）
｛
InitializeComponent();
｝
protected virtual void ProcessFrame( Bitmap bitmap)
{
}
｝
BaseControl的xaml如下：
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" d:DesignHeight ="300" d: DesignWidth="300">
继承BaseControl的子类ChileControl的代码如下：
public partial class ChildControl : CameraControl. MainWindow
{
protected override void Process()
{
//
}
}
当在Windows中使用ChildControl时， 会在BaseControl的InitializeComponent（）方法中抛出异常， “The component does not have a resource identified by the uri”
解决方法是：
替换BaseControl的构造方法里的InitializeComponent。
public partial class BaseControl : UserControl
｛
public BaseControl（）
｛
//InitializeComponent();
this.LoadViewFromUri("/Muzizongheng;component/MainWindow.xaml" );
｝
protected virtual void ProcessFrame( Bitmap bitmap)
{
}
｝
public static class UserControlExtension
{
public static void LoadViewFromUri( this UserControl userControl, string baseUri)
{
try
{
var resourceLocater = new Uri(baseUri, UriKind.Relative);
var exprCa =
( PackagePart)
typeof (Application ).GetMethod("GetResourceOrContentPart",
BindingFlags.NonPublic | BindingFlags .Static).Invoke(null, new object [] {resourceLocater});
Stream stream = exprCa.GetStream();
var uri =
new Uri (
( Uri)
typeof (BaseUriHelper ).GetProperty("PackAppBaseUri",
BindingFlags.Static | BindingFlags .NonPublic).GetValue(null, null), resourceLocater);
var parserContext = new ParserContext
{
BaseUri = uri
};
typeof(XamlReader ).GetMethod("LoadBaml", BindingFlags.NonPublic | BindingFlags .Static)
.Invoke( null, new object[] { stream, parserContext, userControl, true });
}
catch (Exception )
{
}
}
}
The component does not have a resource identified by the uri