C#中可以通過Assembly來動態加載DLL

爲了方便說明一下的方法，先說明一下DLL的代碼，大致如下：

using System;
namespace clsTestDll
{
    /// <summary>
    /// Summary description for TestDll.
    /// </summary>
    public class TestDll
    {
        private string strName;
        public TestDll()
        {
            //
            // TODO: Add constructor logic here
            //
            strName = "";
        }
        public string GetValue( int nCount )
        {
            return string.Format( "Count is {0}!", nCount );
        }
        public static string GetNewValue( int nCount )
        {
            return string.Format( "New count is {0}!", nCount );
        }
        public string Name
        {
            get{ return strName;}
            set{ strName = value;}
        }
    }
}

大致的步驟如下：

首先加載DLL，具體如下：

    // Load assembly from dll file
    Assembly assembly = Assembly.LoadFrom( "clsTestDll.dll");
 
其次，用加載的assembly來定義指定的類型，例如：
    // Create new type
    Type t = assembly.GetType( "clsTestDll.TestDll");

       然後就可以通過新建的類型來調用類的方法。

       如果是類的靜態方法，可以直接調用，如：

    // Call static member function by name
 string strReturn = (string) t.InvokeMember("GetNewValue", BindingFlags.DeclaredOnly|BindingFlags.Public|BindingFlags.Static|BindingFlags.InvokeMethod, null,
      null, new object[]{ 12 } );

 

       如果是類的非靜態方法或屬性，則需要通過類型，先生成類的對象，如：

    // Create new object of specific class name
    Object obj = t.InvokeMember(
        null,
        BindingFlags.DeclaredOnly |
        BindingFlags.Public | BindingFlags.NonPublic |
        BindingFlags.Instance | BindingFlags.CreateInstance,
        null,
        null,
        null );

       接着，就可以通過“obj”對象來進行調用了，如：

    // Call member function by name
        strReturn = (string) t.InvokeMember("GetValue",
        BindingFlags.DeclaredOnly |
        BindingFlags.Public | BindingFlags.NonPublic |
        BindingFlags.Instance | BindingFlags.InvokeMethod,
        null,
        obj,
        new object[]{ 12 } );

    // Set class property
    t.InvokeMember("Name",
        BindingFlags.DeclaredOnly |
        BindingFlags.Public | BindingFlags.NonPublic |
        BindingFlags.Instance | BindingFlags.SetProperty,
        null,
        obj,
        new Object[] {"Test"} )l

    // Get class property

       strReturn = (string) t.InvokeMember("Name",

        BindingFlags.DeclaredOnly |

        BindingFlags.Public | BindingFlags.NonPublic |

        BindingFlags.Instance | BindingFlags.GetProperty,

        null,

        obj,

        null);