如何动态调用DLL中类的方法以及属性

时间:2022-08-31 09:33:06

C#中可以通过Assembly来动态加载DLL,然后由它创建类型,接着通过类型的InvokeMember方法来调用DLL中类的方法以及属性。

 

为了方便说明一下的方法,先说明一下DLL的代码,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;}

        }

    }

}

 

大致的步骤如下:

首先加载DLL,具体如下:

    // Load assembly from dll file

    Assembly assembly = Assembly.LoadFrom( "clsTestDll.dll");  

 

其次,用加载的assembly来定义指定的类型,例如:

    // Create new type

    Type t = assembly.GetType( "clsTestDll.TestDll");

 

       然后就可以通过新建的类型来调用类的方法。

       如果是类的静态方法,可以直接调用,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 } );

 

       如果是类的非静态方法或属性,则需要通过类型,先生成类的对象,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,就可以通过“obj”对象来进行调用了,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"} );

 

    // Get class property

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

        BindingFlags.DeclaredOnly |

        BindingFlags.Public | BindingFlags.NonPublic |

        BindingFlags.Instance | BindingFlags.GetProperty,

        null,

        obj,

        null);

 



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