using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
using System.Data.SqlClient;
using System.Configuration;
namespace biao
{
public partial class Form1 : Form
{
string strcon = string.Empty;
int errorcount = 0;
public Form1()
{
InitializeComponent();
}
private void btn_OK_Click(object sender, EventArgs e)
{
strcon=ConfigurationManager.ConnectionStrings["sqlcnn"].ConnectionString;
int sqlerror = GetError();
if (sqlerror >= 3)
{
#region
/*
DateTime errortime = GetErrorTime();
//Subtract函數減去指定時間，返回一個時間差，這個返回值可以轉換成我們需要的形式，比如可以轉換層總共多少秒，或者總共是多少分
TimeSpan span = DateTime.Now.Subtract(errortime);
double theseconds = span.TotalSeconds;
if (theseconds < 15)
{
MessageBox.Show("您已經連續3次輸入錯誤的密碼，已被系統鎖定，請15秒之後再次重試，或者到服務窗口解鎖！");
return;
}
else
{
errorcount = 0;
UpdateError(errorcount);
}
* */
int secondspan = GetErrorTime1();
if (secondspan < 15)
{
MessageBox.Show("您已經連續3次輸入錯誤的密碼，已被系統鎖定，請15秒之後再次重試，或者到服務窗口解鎖");
return;
}
#endregion
}
#region
//根據用戶輸入的用戶名和密碼驗證是否合法用戶
errorcount = GetError();
DataTable dt = GetDataTable();
if (dt.Rows.Count <= 0)
{
errorcount++;
UpdateError(errorcount);
UpdateErrortime();
MessageBox.Show("輸入的用戶名或者密碼不正確，請重新輸入！");
}
else if (dt.Rows.Count > 1)
{
MessageBox.Show("系統中存在重複的用戶，請聯繫管理員！");
}
else
{
errorcount = 0;
UpdateError(errorcount);
MessageBox.Show("登錄成功");
}
#endregion
}
//f返回當前用戶最後一次的登錄錯誤時間
private DateTime GetErrorTime()
{
SqlConnection conn = new SqlConnection(strcon);
SqlCommand cmd = new SqlCommand();
cmd.Connection = conn;
conn.Open();
cmd.CommandText = "select ErrorTime from T_User where
UserName=@username";
cmd.Parameters.AddWithValue("@username", b_textUser.Text);
object obj = cmd.ExecuteScalar();
return Convert.ToDateTime(obj);
}
//從數據庫中獲取間隔時間
private int GetErrorTime1()
{
SqlConnection conn = new SqlConnection(strcon);
SqlCommand cmd = new SqlCommand();
cmd.Connection = conn;
conn.Open();
cmd.CommandText = "select DATEDIFF([second],ErrorTime,getdate())from T_User where
UserName=@username";
cmd.Parameters.AddWithValue("@username",b_textUser.Text);
//返回一行一列
object obj = cmd.ExecuteScalar();
return Convert.ToInt32(obj);
}
//獲取用戶的登錄錯誤次數
private int GetError()
{
SqlConnection conn = new SqlConnection(strcon);
SqlCommand cmd = new SqlCommand();
cmd.Connection = conn;
conn.Open();
cmd.CommandText = "select Error from T_User where
UserName=@username";
cmd.Parameters.AddWithValue("@username", b_textUser.Text);
object obj = cmd.ExecuteScalar();
//轉換成我們需要的數據類型
if (DBNull.Value.Equals(obj) == true)
{
return 0;
}
else
{
return Convert.ToInt32(obj);
}
}
private void UpdateErrortime()
{
SqlConnection conn = new SqlConnection(strcon);
SqlCommand cmd = new SqlCommand();
cmd.Connection = conn;
conn.Open();
cmd.CommandText = "update T_User set
ErrorTime=@errortime where UserName=@username";
cmd.Parameters.AddWithValue("errortime",DateTime.Now);
cmd.Parameters.AddWithValue("username",b_textUser.Text);
cmd.ExecuteNonQuery();
}
private void UpdateError(int errorcount)
{
SqlConnection conn = new SqlConnection(strcon);
conn.Open();
SqlCommand cmd = new SqlCommand();
cmd.Connection = conn;
cmd.CommandText = "update T_User set Error=@error where
UserName=@username";
cmd.Parameters.AddWithValue("@error", errorcount);
cmd.Parameters.AddWithValue("@username", b_textUser.Text);
cmd.ExecuteNonQuery();
}
private DataTable GetDataTable()
{
SqlConnection conn = new SqlConnection(strcon);
//存儲要像數據庫管理系統發送的一條sql語句
SqlCommand cmd = new SqlCommand();
//指明要像那個數據庫發送sql語句
cmd.Connection = conn;
cmd.CommandText = "select *from T_User where
UserName=@username and Password=@password and Error=0";
//使用用戶輸入的內容替換sql語句中@username佔位符
cmd.Parameters.AddWithValue("@username", this.b_textUser.Text);
cmd.Parameters.AddWithValue("@password", this.b_textPassword.Text);
//數據適配器，向數據庫發送命令
SqlDataAdapter adapter = new SqlDataAdapter(cmd);
//內存中的表格，用來存儲從數據庫中返回的數據
DataTable dt = new DataTable();
adapter.Fill(dt);
//根據datatable對象中的數據的行數來判斷用戶輸入的是否正確
cmd.Dispose();
//關閉連接
conn.Close();
//釋放資源
conn.Dispose();
return dt;
}
}
}