mainfrm.pas

《Delphi 7经典问题解析》源代码 第一到七章 基础篇源程序 应用篇源程序

unit Mainfrm;

interface

uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, DB, DBTables, StdCtrls, OleCtnrs;

type
  TForm1 = class(TForm)
    Database1: TDatabase;
    Table1: TTable;
    Button1: TButton;
    OpenDialog1: TOpenDialog;
    Button2: TButton;
    Doc_Ole: TOleContainer;
    procedure Button1Click(Sender: TObject);
    procedure Button2Click(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;

var
  Form1: TForm1;

implementation

{$R *.dfm}

procedure TForm1.Button1Click(Sender: TObject);
var
  MemSize: Integer;
  Buffer: PChar;
  MyFile: TFileStream;
  Stream: TBlobStream;
begin
  OpenDialog1.Filter := 'WORD文档(*.DOC)|*.DOC'; {从对话窗选择文件}
  if OpenDialog1.Execute then begin
    MyFile := TFileStream.Create(OpenDialog1.FileName, fmOpenRead);
  //判断word文件大小是否大于BDE blobSize属性
    Listparam := TStringlist.Create;
    database1.Session.GetAliasParams('test', ListParam);
    blobSize := strToInt(ListParam.Values['Blob size']);
    if (myfile.Size) div 1024 > blobSize then
      raise exception.Create('word文件大于指定的大小');
   //将Doc文件转换成文件流
    with table1 do
    begin
      Open;
      insert;
      FieldByName('id').Value := 1;
      //将Doc字段的值存到Stream变量中，并标明Stream是可写的
      Stream := TBlobStream.Create(FieldByName('Doc') as TBlobField, bmWrite);
      MemSize := MyFile.Size;
      Inc(MemSize);
      //给缓冲区分配大小
      Buffer := AllocMem(MemSize);
      try
        //将Stream的指针移到最前面
        Stream.Seek(0, soFromBeginning);
        //将MyFile文件流读到Buffer缓冲区中
        MyFile.Read(Buffer^, MemSize);
        //将缓冲区的内容写到Stream
        Stream.Write(Buffer^, MemSize);
      finally
        MyFile.Free;
        Stream.Free;
      end;
      try
        //保存表的修改
        Post;
      except
      end;
    end;
    //Doc_ole是TOleContainer控件，放在窗体上，用它来显示Word文档
    Doc_ole.CreateObjectFromFile(OpenDialog1.FileName, False);
    Doc_ole.Run;
  end;
end;

procedure TForm1.Button2Click(Sender: TObject);
var
  MemSize: Integer;
  Buffer: PChar;
  MyFile: TFileStream;
  Stream: TBlobStream;
begin
  //创建一个临时文件
  MyFile := TFileStream.Create('c:\temp.tmp', fmCreate);
  with Table1 do
  begin
    //将Doc字段的内容读到Stream中
    Stream := TBlobStream.Create
      (FieldByName('Doc') as TBlobField, bmRead);
    MemSize := Stream.Size;
    Inc(MemSize);
    //分配缓冲区的大小
    Buffer := AllocMem(MemSize);
    try
      //将Stream的字节读到Buffer缓冲区中
      Stream.Read(Buffer^, MemSize);
      //将Buffer缓冲区的内容读到MyFile文件流中
      MyFile.Write(Buffer^, MemSize);
    finally
      MyFile.Free;
      Stream.Free;
    end;
  end;
  //如果存在'c:\temp.doc'则删除
  if FileExists('c:\temp.DOC') then
    DeleteFile('c:\temp.DOC');
  if FileExists('c:\temp.tmp') then
  begin
    //重命名临时文件，将其后缀改为.Doc
    RenameFile('c:\temp.tmp', 'c:\temp.DOC');
    //用Doc_Ole控件来显示Word文档
    Doc_ole.CreateObjectFromFile('c:\temp.DOC', False);
    Doc_ole.Run;
  end;
end;
end.