C#可擴展編程之MEF學習筆記（三）：導出類的方法和屬性（轉）
阿新 • • 發佈：2017-11-02
學習 說了 如何 mod ati dem ont num imp 
前面說完了導入和導出的幾種方法，如果大家細心的話會註意到前面我們導出的都是類，那麽方法和屬性能不能導出呢？？？答案是肯定的，下面就來說下MEF是如何導出方法和屬性的。
還是前面的代碼，第二篇中已經提供了下載鏈接，大家可以下載學習。
首先來說導出屬性，因為這個比較簡單，和導出類差不多，先來看看代碼，主要看我加註釋的地方，MusicBook.cs中的代碼如下：
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.ComponentModel.Composition;
namespace MEFDemo
{
[Export("MusicBook")]
public class MusicBook : IBookService
{
//導出私有屬性
[Export(typeof(string))]
private string _privateBookName = "Private Music BookName";
//導出公有屬性
[Export(typeof(string))]
public string _publicBookName = "Public Music BookName";
public string BookName { get; set; }
}
[Export("MathBook", typeof(IBookService))]
public class MathBook : IBookService
{
public string BookName { get; set; }
public string GetBookName()
{
return "MathBook";
}
}
[Export("HistoryBook", typeof(IBookService))]
public class HistoryBook : IBookService
{
public string BookName { get; set; }
public string GetBookName()
{
return "HistoryBook";
}
}
}
program.cs中的代碼如下：
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Reflection;
using System.ComponentModel.Composition;
using System.ComponentModel.Composition.Hosting;
namespace MEFDemo
{
class Program
{
[ImportMany("MathBook")]
public IEnumerable<object> Services { get; set; }
//導入屬性，這裏不區分public還是private
[ImportMany]
public List<string> InputString { get; set; }
static void Main(string[] args)
{
Program pro = new Program();
pro.Compose();
if (pro.Services != null)
{
foreach (var s in pro.Services)
{
var ss = (IBookService)s;
Console.WriteLine(ss.GetBookName());
}
}
foreach (var str in pro.InputString)
{
Console.WriteLine(str);
}
Console.Read();
}
private void Compose()
{
var catalog = new AssemblyCatalog(Assembly.GetExecutingAssembly());
CompositionContainer container = new CompositionContainer(catalog);
container.ComposeParts(this);
}
}
}
下面還用foreach遍歷輸出屬性的值，運行即可查看到結果。最後我會附上源碼供大家下載，這裏就不再截圖了。
下面說導出方法吧，同理無論是公有方法還是私有方法都是可以導出的，MusicBook代碼如下：
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.ComponentModel.Composition;
namespace MEFDemo
{
[Export("MusicBook")]
public class MusicBook : IBookService
{
//導出私有屬性
[Export(typeof(string))]
private string _privateBookName = "Private Music BookName";
//導出公有屬性
[Export(typeof(string))]
public string _publicBookName = "Public Music BookName";
public string BookName { get; set; }
//導出公有方法
[Export(typeof(Func<string>))]
public string GetBookName()
{
return "MusicBook";
}
//導出私有方法
[Export(typeof(Func<int, string>))]
private string GetBookPrice(int price)
{
return "$" + price;
}
}
[Export("MathBook", typeof(IBookService))]
public class MathBook : IBookService
{
public string BookName { get; set; }
public string GetBookName()
{
return "MathBook";
}
}
[Export("HistoryBook", typeof(IBookService))]
public class HistoryBook : IBookService
{
public string BookName { get; set; }
public string GetBookName()
{
return "HistoryBook";
}
}
}
program中的代碼如下：
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Reflection;
using System.ComponentModel.Composition;
using System.ComponentModel.Composition.Hosting;
namespace MEFDemo
{
class Program
{
[ImportMany("MathBook")]
public IEnumerable<object> Services { get; set; }
//導入屬性，這裏不區分public還是private
[ImportMany]
public List<string> InputString { get; set; }
//導入無參數方法
[Import]
public Func<string> methodWithoutPara { get; set; }
//導入有參數方法
[Import]
public Func<int,string> methodWithPara { get; set; }
static void Main(string[] args)
{
Program pro = new Program();
pro.Compose();
if (pro.Services != null)
{
foreach (var s in pro.Services)
{
var ss = (IBookService)s;
Console.WriteLine(ss.GetBookName());
}
}
foreach (var str in pro.InputString)
{
Console.WriteLine(str);
}
//調用無參數方法
if (pro.methodWithoutPara != null)
{
Console.WriteLine(pro.methodWithoutPara());
}
//調用有參數方法
if (pro.methodWithPara != null)
{
Console.WriteLine(pro.methodWithPara(3000));
}
Console.Read();
}
private void Compose()
{
var catalog = new AssemblyCatalog(Assembly.GetExecutingAssembly());
CompositionContainer container = new CompositionContainer(catalog);
container.ComposeParts(this);
}
}
}
導入導出方法用到了Func<T>委托，當然沒有返回值的話可以用Action<T>委托，關於委托這裏就不多說了，大家可以自行百度。
點擊這裏下載源碼
C#可擴展編程之MEF學習筆記（三）：導出類的方法和屬性（轉）