数据库中读写jpeg的函数!

最新推荐文章于 2025-12-10 22:03:01 发布

原创最新推荐文章于 2025-12-10 22:03:01 发布 · 627 阅读

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#数据库 #query #function #string

//写入数据库的方法,可以用文件对话框读到FieldName

function sfSaveJpgToTable(Query:TAdoQuery;FieldName,ImageFileName:String):boolean;
var
Jpg:TJpegImage;
begin
Result:=False;
Jpg:=TJpegImage.Create;
try
   with Query do
   if Active and (RecordCount>0) then
   begin
     Jpg.LoadFromFile(ImageFileName);
     if Not (State in [dsInsert,dsEdit]) then Edit;
     FieldByName(FieldName).Assign(Jpg);
     Post;
     Result:=True;
    end;
except
    jpg.Free;
    Exit;
end;
   Jpg.Free;
end;

//读出 PhotoFieldName是数据库中图片列的名称

function sfShowJpgFromTalbe(Query:TAdoQuery;PhotoFieldName:String;Image:TImage):boolean;
var
    jpg :TJpegImage;
    bs :TStream;
    sImgFile:String;
begin
Result:=False;
jpg := TJpegImage.Create;
try
IF Query.Active and (Query.RecordCount >0) then
begin
    bs := Query.CreateBlobStream(Query.FieldByName(PhotoFieldName),bmRead);
    Image.Picture.Assign(nil);
    if (bs.Size > 0) then
     begin
      jpg.LoadFromStream(bs);
      Image.Picture.Assign(jpg);
     end else
     begin
       sImgFile:='../Image/NoPhoto.jpg';
       if FileExists(sImgFile)
       then image.Picture.LoadFromFile(sImgFile);
     end;
     bs.Free;
     Result:=True;
end else
   begin
    sImgFile:='../Image/NoPhoto.jpg';
    if FileExists(sImgFile)
    then image.Picture.LoadFromFile(sImgFile)
    else image.Picture.Assign(nil);
   end;
except
//MessageDlg('错误','不是JPG文件!',mtError,[mbOk],0);
jpg.Free;
Exit;
end;
jpg.Free;
end;