Delphi下用户登录+识别验证码-源码

unituntLogin;interfaceusesWindows,Messages,SysUtils,Variants,Classes,Graphics,Controls,Forms,Dialogs,StdCtrls,FlatUtils,FlatBtns,FlatCtrls,DB,ADODB,ExtCtrls,SkinCaption,WinSkinData;typeTlogin=class(TForm)btn1:TFlatButton;btn2:TFlatButton;lbl1:TLabel;lbl2:TLabel;con1:TADOConnection;qry1:TADOQuery;edt1:TEdit;edt2:TEdit;img1:TImage;edt3:TEdit;skndt1:TSkinData;skncptn1:TSkinCaption;procedurebtn1Click(Sender:TObject);procedureFormCreate(Sender:TObject);procedureimg1Click(Sender:TObject);procedureedt1KeyPress(Sender:TObject;varKey:Char);procedureedt2KeyPress(Sender:TObject;varKey:Char);procedureedt3KeyPress(Sender:TObject;varKey:Char);procedurebtn2Click(Sender:TObject);private{Privatedeclarations}public{Publicdeclarations}procedureInterData;//加载数据集procedurePwdImg(img:Timage);end;varlogin:Tlogin;username:string;pwdimgstr:string;implementation{$R*.dfm}procedureTlogin.btn1Click(Sender:TObject);beginifEdt1.Text=''then//如果Edit1的文本内容为空,那么beginEdt1.Color:=clWindow;//使edit1的颜色变为红色clRedendelse//否则beginEdt1.Color:=clWindow;//edit1的的颜色为当前组件的表面背景色end;ifEdt2.Text=''thenbeginedt2.Color:=clWindow;//clRedendelsebeginEdt2.Color:=clWindow;end;login.qry1.Active:=false;//关闭数据集login.qry1.SQL.Clear;//清空SQL语句,执行动态SQL查询login.qry1.SQL.Add('select*fromlogin');//从表gzy(公司职员表)中查询所有用户login.qry1.SQL.Add('whereg_name='+quotedstr(trim(edt1.Text)));//条件是用户名等于edit1的文本内容login.qry1.SQL.Add('andg_pwd='+quotedstr(trim(edt2.Text)));//并且密码等于edit2的文本内容login.qry1.Active:=true;//打开数据库ifnotlogin.qry1.Eofthen//.Eof的作用为确定当前的指针是否在数据集的末尾beginiftrim(edt3.Text)<>trim(pwdimgstr)thenbeginshowmessage('验证码不正确');edt3.Clear;PwdImg(img1);endelseifnotlogin.qry1.Fields[3].valuethen//判断Adoquery1字段3的值，值为假则继续执行beginiflogin.qry1.Fields[2].value='超级管理员'then//如果Adoquery1第二个字段的值为'超级管理员'beginShowMessage('登录成功，您是超级管理员！');edt2.Text:='';edt3.Text:='';PwdImg(img1);end;iflogin.qry1.Fields[2].Value='管理员'then//否则如果Adoquery1第二个字段的值为'管理员'beginShowMessage('登录成功，您是管理员！');edt2.Text:='';edt3.Text:='';PwdImg(img1);end;iflogin.qry1.Fields[2].Value='普通用户'then//否则如果Adoquery1第二个字段的值为'普通用户'beginShowMessage('登录成功，您是普通用户！');edt2.Text:='';edt3.Text:='';PwdImg(img1);end;username:=Edt1.Text;//把edit1的值赋给usernameendelsebeginshowmessage('用户已禁用！！');//显示信息end;endelsebeginshowmessage('用户名、密码或验证码错误！！');Edt1.SetFocus;edt1.Clear;edt2.Clear;edt3.Clear;end;end;procedureTlogin.InterData;///初始化目录树////varDataName:string;beginDataName:=ExtractFilePath(Application.ExeName)+'\data.mdb';ifFileExists(DataName)thenbegincon1.Connected:=False;con1.ConnectionString:='Provider=Microsoft.Jet.OLEDB.4.0;'+'DataSource='+DataName+';PersistSecurityInfo=False';con1.LoginPrompt:=false;con1.KeepConnection:=True;con1.Connected:=True;endelsebeginMessageBox(Application.Handle,'数据库文件不存在!','错误',MB_OK);exit;end;qry1.Close;qry1.SQL.Clear;qry1.SQL.Add('select*fromlogin');qry1.Open;end;procedureTlogin.FormCreate(Sender:TObject);beginInterData;PwdImg(img1);end;procedureTlogin.PwdImg(img:Timage);varI,j,k:Integer;vPoint:TPoint;vLeft:Integer;arrStr:array[1..36]ofstring;beginpwdimgstr:='';arrStr[1]:='0';arrStr[2]:='1';arrStr[3]:='2';arrStr[4]:='3';arrStr[5]:='4';arrStr[6]:='5';arrStr[7]:='6';arrStr[8]:='7';arrStr[9]:='8';arrStr[10]:='9';arrStr[11]:='A';arrStr[12]:='B';arrStr[13]:='C';arrStr[14]:='D';arrStr[15]:='E';arrStr[16]:='F';arrStr[17]:='G';arrStr[18]:='H';arrStr[19]:='I';arrStr[20]:='J';arrStr[21]:='K';arrStr[22]:='L';arrStr[23]:='M';arrStr[24]:='N';arrStr[25]:='O';arrStr[26]:='P';arrStr[27]:='Q';arrStr[28]:='R';arrStr[29]:='S';arrStr[30]:='T';arrStr[31]:='U';arrStr[32]:='V';arrStr[33]:='W';arrStr[34]:='X';arrStr[35]:='Y';arrStr[36]:='Z';forj:=1to4dobeginRandomize;k:=strtoint(Format('%.1d',[Random(36)]));pwdimgstr:=pwdimgstr+trim(arrStr[k])end;vLeft:=10;img.picture:=nil;forI:=1toLength(pwdimgstr)dobeginwithImgdobeginCanvas.Font.Size:=Random(10)+9;Canvas.Font.Color:=RGB(Random(256)and$C0,Random(256)and$C0,Random(256)and$C0);ifRandom(2)=1thenCanvas.Font.Style:=[fsBold]elseCanvas.Font.Style:=[];beginCanvas.Font.Name:=Screen.Fonts[10];vPoint.X:=Random(4)+vLeft;vPoint.Y:=Random(5);Canvas.TextOut(vPoint.X,vPoint.Y,pwdimgstr[I]);vLeft:=vPoint.X+Canvas.TextWidth(pwdimgstr[I]);end;end;end;end;procedureTlogin.img1Click(Sender:TObject);beginPwdImg(img1);end;procedureTlogin.edt1KeyPress(Sender:TObject;varKey:Char);beginifkey=#13then//#13为回车键beginedt2.SetFocus;//焦点跳至Button1end;end;procedureTlogin.edt2KeyPress(Sender:TObject;varKey:Char);beginifkey=#13then//#13为回车键