【delphi开源代码栏目提醒】：网学会员鉴于大家对delphi开源代码十分关注，论文会员在此为大家搜集整理了“frm_comms.pas”一文，供大家参考学习

    unit frm_comms;
    
    interface
    
    uses
      Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
      Dialogs, StdCtrls, OleCtrls, MSCommLib_TLB, ComCtrls, XPMan;
    
    const
        ComEvFrame = 1004;     //硬件检测到帧错误 。
        ComEvTxFull = 1010;     //发送缓冲区溢出。
        ComEvRxParity = 1009;  //接收缓冲区溢出。
        ComEvSend = 1;   //发送缓冲区的内容少于SThreshold指定的值。
        ComEvReceive = 2; //接收缓冲区内字符数达到RThreshold指定的值。
    
    type
      TFrmComms = class(TForm)
        Comms: TMSComm;
        GroupBox1: TGroupBox;
        MmMessage: TMemo;
        BtnOpenCom: TButton;
        BtnCloseCom: TButton;
        SBCom: TStatusBar;
        BtnSend: TButton;
        BtnClose: TButton;
        CBxCOM: TComboBox;
        Label1: TLabel;
        procedure BtnOpenComClick(Sender: TObject);
        procedure CommsComm(Sender: TObject);
        procedure FormCreate(Sender: TObject);
        procedure BtnCloseComClick(Sender: TObject);
        procedure BtnSendClick(Sender: TObject);
        procedure BtnCloseClick(Sender: TObject);
      private
        { Private declarations }
      public
        { Public declarations }
      end;
    
    var
      FrmComms: TFrmComms;
    
    implementation
    
    {$R *.dfm}
    
    procedure TFrmComms.BtnOpenComClick(Sender: TObject);
    begin
      try
        Comms.CommPort:=CBxCOM.ItemIndex+1;
        Comms.PortOpen :=true; // 打开串口
        Comms.DTREnable :=true;
        Comms.RTSEnable :=true;
        CBxCom.Enabled:=false;
        SbCom.Panels[0].Text:='端口开启';
      Except
        Showmessage('端口已经打开！');
      end;
    end;
    
    procedure TFrmComms.CommsComm(Sender: TObject);
    var
      recstr:Olevariant;
    begin
      case comms.CommEvent of
      ComEvReceive:
       begin
         recstr := Comms.Input;
         MmMessage.text := MmMessage.Text+recstr;
         sbCom.Panels[1].Text:='接收成功！';
       end;
       ComEvRxParity:
       begin
         sbCom.Panels[1].Text:='接收缓冲区溢出！';
       end;
       ComEvFrame:
       begin
         sbCom.Panels[1].Text:='硬件检测到帧错误！';
       end;
       ComEvTxFull:
       begin
         sbCom.Panels[1].Text:='发送缓冲区溢出！';
       end;
      end;
    end;
    
    procedure TFrmComms.FormCreate(Sender: TObject);
    begin
      Comms.InBufferCount :=0;
      Comms.InputLen :=0;
      Comms.RThreshold :=1;
    end;
    
    procedure TFrmComms.BtnCloseComClick(Sender: TObject);
    begin
      try
        Comms.PortOpen :=false; // 关闭串口
        Comms.DTREnable :=false;
        Comms.RTSEnable :=false;
        CBxCom.Enabled:=true;
        SbCom.Panels[0].Text:='端口关闭';
      except
        showmessage('没有开启的端口！');
      end;
    end;
    
    procedure TFrmComms.BtnSendClick(Sender: TObject);
    begin
      Comms.Output:=MmMessage.Text;
    end;
    
    procedure TFrmComms.BtnCloseClick(Sender: TObject);
    begin
      Close;
    end;
    
    end.