一.建立dll
菜单File --> New -->Other,弹出New Items 窗体,选择New页的DLL Wizard,点击OK.
弹出DLL Wizard窗体,默认选项即可(C++选中,Use VCL选中,Multi Threaded为灰色不可用)
点击OK.
在代码窗体中输入如下内容:
// --------------------------------------------------------------------------- #include <vcl.h> #include <vector> #include <windows.h> #pragma hdrstop // --------------------------------------------------------------------------- // dll函数的外部接口 //std::vector<int>函数的返回值 //pv (std::vector<int>v)为函数名和函数的参数 extern "C" __declspec(dllexport) std::vector<int>__stdcall pv (std::vector<int>v); #pragma argsused int WINAPI DllEntryPoint(HINSTANCE hinst, unsigned long reason, void* lpReserved) { return 1; } // --------------------------------------------------------------------------- // dll函数的实现-- std::vector<int>__stdcall pv(std::vector<int>v) { if (v.size() > 0) { v.clear(); } for (int i = 0; i < 10; i++) { v.push_back(i); } return v; }
建立一个应用程序,在窗体上1个Button,2个Edit控件.
要实现在Edit1里输入一个数字,点击button按钮,调用dll的函数后,将返回值返回到Edit2控件中.
首先保存项目,之后把上面编译后的Project1.dll拷贝到现在的目录.
双击button1控件,在代码窗体中输入如下代码:
// --------------------------------------------------------------------------- #include <vcl.h> #pragma hdrstop #include <vector> #include <stdio.h> #include "Unit1.h" // --------------------------------------------------------------------------- #pragma package(smart_init) #pragma resource "*.dfm" TForm1 *Form1; // --------------------------------------------------------------------------- __fastcall TForm1::TForm1(TComponent* Owner) : TForm(Owner) { } // --------------------------------------------------------------------------- void __fastcall TForm1::Button1Click(TObject *Sender) { std::vector<int>v; HINSTANCE ins; String dllfn = "Project1.dll"; // wchar_t *tmp=dllfn.w_str(); LPCTSTR tmp = dllfn.w_str(); // 这样是解决Unicode字符匹配问题 ins = ::LoadLibrary(tmp); if (ins == NULL) { throw "Can't load library!"; } else { std::vector<int>(__stdcall *p)(std::vector<int>); // 定义数据类型 p = (std::vector<int>__stdcall(*)(std::vector<int>))::GetProcAddress (ins, "pv"); if (p == NULL) { FreeLibrary(ins); throw "Can't Load Address!"; } else { v = p(v); Edit1->Text = v[0]; Edit2->Text = v[9]; } } if (!FreeLibrary(ins)) { throw "Can't Free!"; } } // ---------------------------------------------------------------------------