我尝试了一段时间使用MEF完成任务,但现在遇到了问题,我需要帮助。导入属性始终为空(MEF导入问题)
描述: 我有2个DLL和一个EXE文件。 ClassLibrary1的(LoggerImpl.cs,SomeClass.cs) ClassLibrary2(ILogger.cs) WindowsApplicationForms1(WindowsApplicaitonForms1.cs,Program.cs中)
我需要任何帮助或指导为什么不起作用?
// ClassLibrary1.dll
//SomeClass.cs
public class SomeClass
{
[Import("Logging", typeof(ILogger))]
public ILogger Log { get; set; } <-- ALWAYS NULL ???
public void Print()
{
Log.Print();
}
}
// ClassLibrary1.dll
// LoggerImpl.cs
namespace ClassLibrary1
{
[Export("Logging", typeof (ILogger))]
public class LoggerImpl : ILogger
{
public void Print()
{
Console.WriteLine("print called");
}
}
}
// ClassLibrary2.dll
// ILogger.cs
namespace LogNamespace
{
public interface ILogger
{
void Print();
}
}
// WindowsFormsApplication1.exe
// WindowsFormsApplication1.cs
namespace WindowsFormsApplication1
{
[Export("Form1",typeof(Form1))]
public partial class Form1 : Form
{
[Import("Logging", typeof(ILogger))]
public ILogger Log { set; get; }
private CompositionContainer _container;
public Form1()
{
InitializeComponent();
Compose();
Log.Print();
SomeClass c = new SomeClass();
c.Print();
}
private void Compose()
{
var catalog = new AggregateCatalog();
catalog.Catalogs.Add(new DirectoryCatalog("."));
catalog.Catalogs.Add(new AssemblyCatalog(System.Reflection.Assembly.GetExecutingAssembly()));
_container = new CompositionContainer(catalog);
try
{
_container.ComposeParts(this);
}
catch (CompositionException compositionException)
{
MessageBox.Show(compositionException.ToString());
}
}
}
}
你'SomeClass'不参与组成,因此它的进口量将永远不会被设置。 – dtb