net教学之登录页面

net教学之登录页面 效果图: 流程: 1、用户名和密码都正确时，转向welcome.aspx页面。 2、用户名正确，密码不正确，可以尝试三次，三次都错误，不允许登录。 3、用户名不正确，可以尝试三次，三次都错误，不允许登录。 关键代码: public partial class login : System.Web.UI.Page { protected void Page_Load(object sender, EventArgs e) { } protected void btn_reg_Click(object sender, EventArgs e)//注册按钮 { Response.Redirect("reguser.aspx"); } static int n, m;//静态变量，控制试错次数 protected void btn_login_Click(object sender, EventArgs e)//登录按钮 { string constr = ConfigurationManager.ConnectionStrings["ApplicationServices"].ConnectionString; string sql1 = "select * from [user] where id='" + txb_id.Text.Trim() + "'"; string sql2 = "select * from [user] where pwd='" + txb_pwd.Text.Trim() + "' and id='"+txb_id.Text.Trim()+"'"; bool i, j; SqlConnection con = new SqlConnection(constr); try { con.Open(); SqlCommand com1 = new SqlCommand(sql1, con); SqlCommand com2 = new SqlCommand(sql2, con); SqlDataReader reader1 = com1.ExecuteReader(); i = reader1.HasRows; reader1.Close(); SqlDataReader reader2 = com2.ExecuteReader(); j = reader2.HasRows; reader2.Close(); if (i) { if (j) { Response.Redirect("welcome.aspx?id=" + txb_id.Text + "");//向welcome.aspx页面传递参数id } else { n = n + 1; if (n < 3) { Response.Write(""); txb_pwd.Text = ""; } else { Response.Write(""); txb_id.ReadOnly = true; txb_pwd.ReadOnly = true; } } } else { m = m + 1; if (m < 3) { Response.Write(""); txb_id.Text = ""; txb_pwd.Text = ""; } else { Response.Write(""); txb_id.ReadOnly = true; txb_pwd.ReadOnly = true; } } } catch (SqlException ex) { Response.Write(""); } finally { con.Close(); } } }