求大神逐句解释下,感谢!!!
发布网友
发布时间：2022-04-30 07:08
共3个回答
懂视网
时间：2022-04-30 11:29
首先创建windows窗体应用程序，然后拖出登录界面
2. 写配置文件App.config:
????<configuration>
????????<connectionStrings>
????????<add name="mssqlserver" connectionString="Data Source=.;Initial Catalog=test;User ID=sa;Password=1q2w3e4R"/>
????????</connectionStrings>
</configuration>
其中的name可以随意去写，没有任何限制。连接字符串中的【Data Source=.】为服务器名称，【Initial Catalog-test】为表名，后面的为用户名和密码。
3. 写SqlHelper代码：
????3.1 读取配置文件：
????????·首先要添加引用:System.Configuration
????????·然后读取连接字符串：
????????????private static readonly string connStr = ConfigurationManager.ConnectionStrings["mssqlserver"].ConnectionString;
????3.2 封装常用的方法
????????·执行insert/delete/update的方法
????????????public static int ExecuteNonQuery(string sql, CommandType cmdType, params SqlParameter[] pms)
????????{
//创建连接对象
????using (SqlConnection con = new SqlConnection(connStr))
????{
//创建命令对象
???? using (SqlCommand cmd = new SqlCommand(sql, con))
????{
//设置当前执行的是存储过程还是带参数的Sql语句
cmd.CommandType = cmdType;
//判断是否传递参数 注意：如果传递的不是数组类型，那么不去判空也不会报错，但是如果是数组类型，那么就会报错。所以为了保险起见，应该进行判空。
if (pms != null)
{
cmd.Parameters.AddRange(pms);
}
con.Open();
return cmd.ExecuteNonQuery();
????}
????}
????????}
????????·执行返回单个值的方法
????????????public static object ExecuteScalar(string sql, CommandType cmdType, params SqlParameter[] pms)
????????{
????using (SqlConnection con = new SqlConnection(connStr))
????{
????using (SqlCommand cmd = new SqlCommand(sql, con))
????{
cmd.CommandType = cmdType;
if (pms != null)
{
cmd.Parameters.AddRange(pms);
}
con.Open();
return cmd.ExecuteScalar();
????}
????}
????????}
????????·返回SqlDataReader的方法
????????????public static SqlDataReader ExecuteReader(string sql, CommandType cmdType, params SqlParameter[] pms)
????????{
????SqlConnection con=new SqlConnection(connStr);
????using (SqlCommand cmd = new SqlCommand(sql, con))
????{
????cmd.CommandType = cmdType;
????if (pms != null)
????{
cmd.Parameters.AddRange(pms);
????}
????try
????{
con.Open();
return cmd.ExecuteReader(CommandBehavior.CloseConnection);
????}
????catch
????{
con.Close();
con.Dispose();
throw;
????}
????}
????????}
????????·执行返回DataTable方法
????????????public static DataTable ExecuteDataTable(string sql, CommandType cmdType, params SqlParameter[] pms)
????????{
????DataTable dt=new DataTable();
????using (SqlDataAdapter adapter = new SqlDataAdapter(sql, connStr))
????{
adapter.SelectCommand.CommandType = cmdType;
if (pms != null)
????{
adapter.SelectCommand.Parameters.AddRange(pms);
????}
adapter.Fill(dt);
return dt;
????}
????????}
4. 执行登录操作：
????????private void button1_Click(object sender, EventArgs e)
????{
string sql = "select COUNT(*) from users where loginId=@uid and loginPwd=@pwd";
SqlParameter[] pms=new SqlParameter[]
{
new SqlParameter("@uid",textBox1.Text.Trim()),
new SqlParameter("@pwd",textBox2.Text)
};
int n=(int) SqlHelper.ExecuteScalar(sql, CommandType.Text, pms);
if (n > 0)
{
MessageBox.Show("成功！");
}
else
{
MessageBox.Show("失败!");
}
????}
通过SqlHelper实现登录
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热心网友
时间：2022-04-30 08:37
{
if(String.Compare(Request.Cookies["CheckCode"].Value,txtPng.Text.ToString().Trim(), true) != 0)
{
CommonLib.JavaScriptHelper.Alert("验证码不正确！", Page);//判断验证码输入是否正确
txtPng.Text = "";//把验证码输入框值转为空
return;
}
else
{
string con =CommonLib.SqlHelper.SqlConnectionString;// 访问数据库
string user =CommonLib.CutString.CutHTML(txtUserName.Text.Trim());//用户名
string pwd =txtPwd.Text.Trim();//密码
string sql = "select count(*)from manager where manager_name='" + user
+ "' andmanager_pwd='" + pwd + "'";
int count =Convert.ToInt32(CommonLib.SqlHelper.ExecuteScalar(con, CommandType.Text, sql,null));
if (count > 0) //判断用户名或密码是否正确
{
HttpCookie cookies =Request.Cookies["T-TXB"];
cookies = newHttpCookie("T-TXB");
cookies.Values.Add("Manager",HttpUtility.UrlEncode(txtUserName.Text.Trim()));
Response.Cookies.Set(cookies);//存储！～
CommonLib.JavaScriptHelper.Redirect("mainframe.aspx");
}
else
{
CommonLib.JavaScriptHelper.Alert("用户名或密码错误！", Page);
}
}
热心网友
时间：2022-04-30 09:55
protected voidbtnLogin_Click(object sender, EventArgs e)
{
//从cookies获取"checkcode"值，进行对比
if(String.Compare(Request.Cookies["CheckCode"].Value,txtPng.Text.ToString().Trim(), true) != 0)
{// 弹出错误提示
CommonLib.JavaScriptHelper.Alert("验证码不正确！", Page);
txtPng.Text = "";
return;
}
else
{
string con =CommonLib.SqlHelper.SqlConnectionString;//连接数据库
string user =CommonLib.CutString.CutHTML(txtUserName.Text.Trim());//获取用户名
string pwd =txtPwd.Text.Trim();//获取密码
string sql = "select count(*)from manager where manager_name='" + user
+ "' andmanager_pwd='" + pwd + "'";//拼接SQL，查询有无当前用户名密码的用户
int count =Convert.ToInt32(CommonLib.SqlHelper.ExecuteScalar(con, CommandType.Text, sql,null));
if (count > 0)//如果有查询记录，进入if
{
HttpCookie cookies =Request.Cookies["T-TXB"];
cookies = newHttpCookie("T-TXB");//新建一个cookies "T-TXB"
cookies.Values.Add("Manager",HttpUtility.UrlEncode(txtUserName.Text.Trim()));
Response.Cookies.Set(cookies);//存储新建的值
CommonLib.JavaScriptHelper.Redirect("mainframe.aspx");
}
else
{
CommonLib.JavaScriptHelper.Alert("用户名或密码错误！", Page);
}
}
