文档介绍:unitUnit1;interfaceusesWindows,Messages,SysUtils,Variants,Classes,Graphics,Controls,Forms,Dialogs,StdCtrls,DB,ADODB,jpeg,ExtCtrls;typeTForm1=class(TForm)ADOConnection1:TADOConnection;ADOQuery1:TADOQuery;Edit1:TEdit;Edit2:TEdit;Button1:TButton;Button2:TButton;ADOTable1:TADOTable;Image1:TImage;Label1:TLabel;Label2:TLabel;Label3:TLabel;Label4:TLabel;Button3:TButton;procedureButton1Click(Sender:TObject);procedureButton2Click(Sender:TObject);procedureButton3Click(Sender:TObject);private{Privatedeclarations}ount:integer;{Publicdeclarations}end;varForm1:TForm1;implementationusesUnit12,Unit19;{$R*.dfm}(Sender:TObject);varyonghu:string;beginyonghu:=trim();//trim去除字符串空格count:=count+1;//登陆次数withadoquery1dobeginClose;:='select*from用户信息表where用户名='''+yonghu+'''';open;if(<>0)and(<>'')and(('密码').AsString=)('是否管理员').AsString='True':=true;:=true;('密码正确,即将进入系统。','提示',mb_ok);;;:=false;:=false;('密码正确,即将进入系统。','提示',mb_ok);;;end;endelsebeginif(count=1)thenbegin('用户名或密码错误,还剩2次机会','提示',mb_ok);;//光标是向左对齐的也就是在编辑框的最左边end;if(count=2)thenbegin('您还有最后一次机会,请仔细核对用户名和密码','提示',mb_ok);;;;end;if(count=3)thenbegin('密码错误超过三次系统即将关闭','提示',mb_ok);;//退出程序end;end;end;end;(Sender:TObject);beginJend;(Sender:TObject);;end;;interfaceusesWindows,Messages,SysUtils,Variants,Classes,Graphics,Controls,Forms,Dialogs,StdCtrls,Grids,DBGrids,jpeg,ExtCtrls,DB,ADODB;typeTForm2=class(TForm)Image1:TImage;Label1:TLabel;GroupBox1:TGroupBox;DBGrid1:TDBGrid;Button1:TButton;GroupBox2:TGroupBox;GroupBox3:TGroupBox;GroupBox4:TGroupBox;Label3:TLabel;Label4:TLabel;Edit1:TEdit;Edit2:TEdit;Label5:TLabel;RadioB