C++检测网络连接是否正常

//--------------------------------------------------------------------------- //Download by http://www.codefans.net #include <vcl.h> #pragma hdrstop #include "Mainform.h" //--------------------------------------------------------------------------- #pragma package(smart_init) #pragma resource "*.dfm" TForm1 *Form1; //--------------------------------------------------------------------------- __fastcall TForm1::TForm1(TComponent* Owner) : TForm(Owner) { } //--------------------------------------------------------------------------- void __fastcall TForm1::BitBtn1Click(TObject *Sender) { NMEcho1->ReportLevel = Status_Basic; NMEcho1->TimeOut = StrToInt(Edit5->Text); NMEcho1->Host = Edit2->Text; NMEcho1->Port = StrToInt(Edit3->Text); NMEcho1->Connect(); } //--------------------------------------------------------------------------- void __fastcall TForm1::BitBtn2Click(TObject *Sender) { NMEcho1->Disconnect(); } //--------------------------------------------------------------------------- void __fastcall TForm1::NMEcho1Connect(TObject *Sender) { StatusBar1->SimpleText = "连接成功！"; } //--------------------------------------------------------------------------- void __fastcall TForm1::NMEcho1ConnectionFailed(TObject *Sender) { StatusBar1->SimpleText = "连接失败！"; } //--------------------------------------------------------------------------- void __fastcall TForm1::Button1Click(TObject *Sender) { Edit4->Text = NMEcho1->Echo(Edit1->Text); } //--------------------------------------------------------------------------- void __fastcall TForm1::Button4Click(TObject *Sender) { NMEcho1->Abort(); } //--------------------------------------------------------------------------- void __fastcall TForm1::NMEcho1Disconnect(TObject *Sender) { if (StatusBar1 != 0) StatusBar1->SimpleText = "连接已经被断开！"; } //--------------------------------------------------------------------------- void __fastcall TForm1::NMEcho1HostResolved(TComponent *Sender) { StatusBar1->SimpleText = "成功解析远程主机域名！"; } //--------------------------------------------------------------------------- void __fastcall TForm1::NMEcho1InvalidHost(bool &Handled) { AnsiString NewHost; if (InputQuery("远程主机域名无效！", "请重新选择远程主机", NewHost)) { NMEcho1->Host = NewHost; Handled = true; } } //--------------------------------------------------------------------------- void __fastcall TForm1::NMEcho1Status(TComponent *Sender, AnsiString Status) { if (StatusBar1 != 0) StatusBar1->SimpleText = Status; } //--------------------------------------------------------------------------- void __fastcall TForm1::NMEcho1ConnectionRequired(bool &Handled) { if (MessageBox(0, "是否需要连接远程主机？", "信息提示", MB_YESNO + MB_ICONEXCLAMATION) == IDYES) { Handled = true; Button1Click(NULL); } } //---------------------------------------------------------------------------