Delphi使用兩種方法獲取Windows系統的端口，還可測試發送消息，點擊獲取端口信息後，可依次得到如下信息：DCB結構大小、波特率大小、XON的臨界值、XOFF的臨界值、字符位數、奇偶檢驗位、停止位、XON字符等，也可設置端口信息，設置SPCOMM端口信息：
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unit Unit1;
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interface
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uses
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Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
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Dialogs, SPComm, StdCtrls, ComCtrls;
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type
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TForm1 = class(TForm)
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Edit1: TEdit;
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Button2: TButton;
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Memo1: TMemo;
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Button3: TButton;
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Button1: TButton;
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Label1: TLabel;
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Button4: TButton;
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Comm1: TComm;
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Edit2: TEdit;
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Button5: TButton;
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StatusBar1: TStatusBar;
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procedure Button2Click(Sender: TObject);
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procedure Button3Click(Sender: TObject);
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procedure Button1Click(Sender: TObject);
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procedure Button4Click(Sender: TObject);
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procedure Button5Click(Sender: TObject);
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procedure FormDestroy(Sender: TObject);
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private
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{ Private declarations }
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public
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{ Public declarations }
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end;
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var
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Form1: TForm1;
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implementation
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{$R *.dfm}
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procedure TForm1.Button2Click(Sender: TObject);
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var
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CommPort : string;
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hCommFile : THandle;
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hdcb:DCB;
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begin
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commport:=Edit1.Text;
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hCommFile := CreateFile(PChar(CommPort),GENERIC_READ or GENERIC_WRITE,
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0,nil,OPEN_EXISTING,FILE_ATTRIBUTE_NORMAL,0);
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//打開端口失敗的處理
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if hCommFile =INVALID_HANDLE_VALUE then
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Statusbar1.SimpleText:='不能打開端口';
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GetCommState(hcommFile,hdcb); //獲取DCB結構信息
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Memo1.Clear;
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Memo1.Lines.Add('DCB結構大小是：'+IntToStr(hdcb.DCBlength)+#13#10+
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'波特率大小是： '+IntToStr(hdcb.BaudRate)+#13#10+
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'XON的臨界值是：'+IntToStr(hdcb.XonLim)+#13#10+
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'XOFF的臨界值是：'+IntToStr(hdcb.XoffLim)+#13#10+
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'字符位數是：'+IntToStr(hdcb.ByteSize)+#13#10+
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'奇偶檢驗位：'+IntToStr(hdcb.Parity)+#13#10+
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'停止位：'+IntToStr(hdcb.StopBits)+#13#10+
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'XON字符：'+hdcb.XonChar+#13#10+
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'XOFF字符：'+hdcb.XoffChar+#13#10+
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'奇偶錯誤代替字符：'+hdcb.ErrorChar+#13#10+
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'結束字符：'+hdcb.EofChar+#13#10+
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'時間字符：'+hdcb.EvtChar+#13#10);
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CloseHandle(hcommfile);
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//關閉端口句柄，否則重新執行程序時會調用空句柄，不能得到正確的參數值
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end;
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procedure TForm1.Button3Click(Sender: TObject);
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var
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CommPort : string;
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hCommFile : THandle;
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Buffer : PCommConfig;
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size : DWord;
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begin
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CommPort := 'COM2';
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hCommFile := CreateFile(PChar(CommPort),
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GENERIC_WRITE,
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0,
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nil,
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OPEN_EXISTING,
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FILE_ATTRIBUTE_NORMAL,
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0);
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if hCommFile=INVALID_HANDLE_VALUE then
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begin
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Statusbar1.SimpleText:='不能打開 '+ CommPort;
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exit;
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end;
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GetMem(Buffer, sizeof(TCommConfig));
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GetCommConfig(hCommFile, Buffer^, size);
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FreeMem(Buffer, sizeof(TCommConfig));
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GetMem(Buffer, size);
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GetCommConfig(hCommFile, Buffer^, size);
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if CommConfigDialog(PChar(CommPort),Handle,Buffer^) = true then
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SetCommConfig(hCommFile, Buffer^, size);
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FreeMem(Buffer, size);
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CloseHandle(hCommFile);
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end;
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procedure TForm1.Button1Click(Sender: TObject);
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var
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setComm : string;
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hsetFile : THandle;
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hsetdcb:DCB;
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begin
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//設置斷口信息
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setcomm:=Edit1.Text;
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hsetFile := CreateFile(PChar(setComm),GENERIC_READ or GENERIC_WRITE,
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0,nil,OPEN_EXISTING,FILE_ATTRIBUTE_NORMAL,0);
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//打開端口失敗的處理
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if hsetFile =INVALID_HANDLE_VALUE then
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Statusbar1.SimpleText:='不能打開端口';
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GetCommState(hsetFile,hsetdcb);
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hsetdcb.BaudRate:=2400;
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hsetdcb.StopBits:=2;
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hsetdcb.ByteSize:=4;
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SetCommState(hsetFile,hsetdcb); //獲取DCB結構信息
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closeHandle(hsetfile); //關閉端口
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end;
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procedure TForm1.Button4Click(Sender: TObject);
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begin
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comm1.StopComm; //先關閉端口
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{設置一些必要的參數}
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Comm1.CommName:=Edit1.Text;
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Comm1.BaudRate:=9600;
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Comm1.ByteSize:=_8;
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Comm1.StopBits:=_1;
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Comm1.Parity:=None;
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Try
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comm1.StartComm; //打開端口
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except
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raise Exception.create('打開端口'+comm1.CommName+'出錯了');
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end;
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Statusbar1.SimpleText:=Comm1.CommName+'打開了';
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Button5.Enabled:=True;
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end;
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procedure TForm1.Button5Click(Sender: TObject);
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var str:string;
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count:Word;
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begin
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str:=pchar(Edit2.Text);
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count:=length(str);
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If comm1.WriteCommData(pchar(str),count) Then
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Statusbar1.SimpleText:='已經發送'+IntToStr(count)+'字符'
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Else
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Statusbar1.SimpleText:='發送不成功';
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end;
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procedure TForm1.FormDestroy(Sender: TObject);
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begin
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Comm1.StopComm; //關閉端口
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end;
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end.
最終運行截圖如下圖：
