delphi xe 电子秤 代码

以下是一个简单的 Delphi XE 电子秤应用程序的示例代码，通过串口通信读取秤的重量数据：

unit Unit1;

interface

uses
  Winapi.Windows, Winapi.Messages, System.SysUtils, System.Variants, System.Classes, Vcl.Graphics,
  Vcl.Controls, Vcl.Forms, Vcl.Dialogs, Vcl.StdCtrls, Vcl.ExtCtrls, Vcl.ComCtrls;

type
  TForm1 = class(TForm)
    Memo1: TMemo;
    Timer1: TTimer;
    procedure FormCreate(Sender: TObject);
    procedure Timer1Timer(Sender: TObject);
    procedure FormClose(Sender: TObject; var Action: TCloseAction);
  private
    { Private declarations }
    FComHandle: THandle;
    FWeight: Double;
    function OpenCom(Port: Integer): Boolean;
    procedure CloseCom;
    function ReadCom(var Buffer; Count: Integer): Integer;
    function FindCom: Integer;
    procedure ParseWeight(const Data: AnsiString);
  public
    { Public declarations }
  end;

var
  Form1: TForm1;

implementation

{$R *.dfm}

const
  CRLF = #13#10;

procedure TForm1.CloseCom;
begin
  if FComHandle <> INVALID_HANDLE_VALUE then
  begin
    CloseHandle(FComHandle);
    FComHandle := INVALID_HANDLE_VALUE;
  end;
end;

function TForm1.FindCom: Integer;
var
  i: Integer;
  ComName: string;
  DCB: TDCB;
begin
  Result := 0;
  for i := 1 to 16 do
  begin
    ComName := '\\.\COM' + IntToStr(i);
    FComHandle := CreateFile(PChar(ComName), GENERIC_READ or GENERIC_WRITE, 0, nil, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, 0);
    if FComHandle <> INVALID_HANDLE_VALUE then
    begin
      FillChar(DCB, SizeOf(DCB), 0);
      DCB.DCBlength := SizeOf(DCB);
      if GetCommState(FComHandle, DCB) then
      begin
        DCB.BaudRate := CBR_9600;
        DCB.ByteSize := 8;
        DCB.Parity := NOPARITY;
        DCB.StopBits := ONESTOPBIT;
        DCB.XonChar := #11;
        DCB.XoffChar := #13;
        if SetCommState(FComHandle, DCB) then
        begin
          Result := i;
          break;
        end;
      end;
      CloseHandle(FComHandle);
      FComHandle := INVALID_HANDLE_VALUE;
    end;
  end;
end;

function TForm1.OpenCom(Port: Integer): Boolean;
begin
  Result := False;
  FComHandle := CreateFile(PChar('\\.\COM' + IntToStr(Port)), GENERIC_READ or GENERIC_WRITE, 0, nil, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, 0);
  if FComHandle <> INVALID_HANDLE_VALUE then
  begin
    Result := True;
  end;
end;

function TForm1.ReadCom(var Buffer; Count: Integer): Integer;
begin
  if FComHandle = INVALID_HANDLE_VALUE then
  begin
    Result := 0;
    Exit;
  end;
  ReadFile(FComHandle, Buffer, Count, Result, nil);
end;

procedure TForm1.Timer1Timer(Sender: TObject);
var
  Data: AnsiString;
  Buffer: array [0..255] of AnsiChar;
  BytesRead: DWORD;
begin
  if FComHandle = INVALID_HANDLE_VALUE then
  begin
    Memo1.Lines.Add('正在查找电子秤...');
    if FindCom > 0 then
    begin
      Memo1.Lines.Add('电子秤已连接，正在打开串口...');
      if not OpenCom(FindCom) then
      begin
        Memo1.Lines.Add('打开串口失败！');
        Exit;
      end;
      Memo1.Lines.Add('串口已打开，正在读取数据...');
    end
    else
    begin
      Exit;
    end;
  end;
  if ReadCom(Buffer, SizeOf(Buffer)) > 0 then
  begin
    Data := Data + AnsiString(Buffer);
    if Pos(CRLF, Data) > 0 then
    begin
      ParseWeight(Data);
      Data := '';
    end;
  end;
end;

procedure TForm1.ParseWeight(const Data: AnsiString);
var
  S: AnsiString;
  P: Integer;
begin
  S := Trim(Data);
  P := Pos(' ', S);
  if P > 0 then
  begin
    S := Copy(S, 1, P - 1);
    FWeight := StrToFloatDef(S, 0);
    Memo1.Lines.Add(Format('重量：%f', [FWeight]));
  end;
end;

procedure TForm1.FormClose(Sender: TObject; var Action: TCloseAction);
begin
  CloseCom;
end;

procedure TForm1.FormCreate(Sender: TObject);
begin
  FComHandle := INVALID_HANDLE_VALUE;
  FWeight := 0;
end;

end.

注意：上述代码仅供参考，具体实现可能需要根据具体的电子秤型号和通讯协议进行调整。