unit2.cpp

CBUILDER+SQL的实现

//---------------------------------------------------------------------------

#include <vcl.h>
#pragma hdrstop

#include "Unit2.h"
#include "Unit1.h"
#include "Unit9.h"

//---------------------------------------------------------------------------
#pragma package(smart_init)
#pragma resource "*.dfm"
TForm2 *Form2;
//---------------------------------------------------------------------------
__fastcall TForm2::TForm2(TComponent* Owner)
        : TForm(Owner)
{
}
//---------------------------------------------------------------------------


void __fastcall TForm2::Button1Click(TObject *Sender)
{
    
    if(Form1->Database1->Connected==false)//数据库尚未连接
    {
    Form1->Database1->LoginPrompt=false;

    Form1->Database1->Params->Values["User Name"]="use_user";
    Form1->Database1->Params->Values["Password"]="user";   
    try
     {
      Form1->Database1->Connected=true;
      Query1->Active=true;
     }
     catch(Exception &e)
       {MessageBox(NULL,"与数据库连接失败","信息提示",MB_OK);}
    }
if(Form1->Database1->Connected==true)//连接成功
 {
    try
  {
   Query1->Close();
   Query1->SQL->Clear();
   AnsiString strSQL="select *  from Users ";
      strSQL+="where user_name='"+Edit1->Text+"'";
   Query1->SQL->Add(strSQL);
    Query1->ExecSQL();//执行语句
    Query1->Open();

    if(Query1->RecordCount!=0)//帐号合法
     {
      if(Query1->FieldByName("password")->AsString==Edit2->Text) //密码吻合
        { //判断用户类型
            if(Query1->FieldByName("type")->AsString=="管理员")
                {
               Form1->Database1->Connected=false;//查询后关闭数据库连接
               Form1->Database1->Params->Values["UserName"]="admin";
               Form1->Database1->Params->Values["Password"]="admin";
                Form1->N7->Visible=true;  //显示缴费管理菜单
               Form1->N6->Visible=true; //显示报到单管理菜单
               Form1->N8->Visible=true;  //显示宿舍管理菜单
               Form1->N9->Visible=true;  //显示用户管理菜单
               Form1->N10->Visible=true;  //显示新生数据管理菜单
                }
        else if(Query1->FieldByName("type")->AsString=="收费用户")
           {
               Form1->Database1->Connected=false;//查询后关闭数据库连接
               Form1->Database1->Params->Values["UserName"]="charge";
               Form1->Database1->Params->Values["Password"]="charge";
               Form1->N7->Visible=true;  //显示缴费管理菜单
               Form1->N6->Visible=true; //显示报到单管理菜单
               Form1->N8->Visible=true;  //显示宿舍管理菜单
           }
        else if(Query1->FieldByName("type")->AsString=="一般用户")
            {
             Form1->Database1->Connected=false;//查询后关闭数据库连接
             Form1->Database1->Params->Values["UserName"]="liuchuqun";
             Form1->Database1->Params->Values["Password"]="liuchuqun";
              Form1->N6->Visible=true; //显示报到单管理菜单
              Form1->N8->Visible=true;  //显示宿舍管理菜单

            }
        try    //得到用户类型后重新 连接数据库
        {
          Form1->Database1->Connected=true;
           Query1->Active=true;
           Form1->N2->Enabled=false;
           Form1->N3->Enabled=true;
           Form9->Label1->Caption=Edit1->Text;//保存用户名
           Form1->StatusBar1->SimpleText="当前活动用户 ："+Edit1->Text;
           Form2->Close();
MessageBox(NULL,"登陆成功！","信息提示",MB_OK);
        }
        catch(Exception &e)
         {
         MessageBox(NULL,"用户连接数据库失败！","信息提示",MB_OK);
         }
      } //if密码正确
      else{ MessageBox(NULL,"密码错误！数据库连接失败","信息提示",MB_OK);}
      } //if帐户存在
    else {MessageBox(NULL,"此帐号不存在！","信息提示",MB_OK);}
}
catch(Exception &e)
{MessageBox(NULL,"与数据库连接失败","信息提示",MB_OK);}
}

}
//---------------------------------------------------------------------------

void __fastcall TForm2::Button2Click(TObject *Sender)
{
Close();        
}
//---------------------------------------------------------------------------