Question

这根本不起作用。我已经做过很多次了，但是我不知道出了什么问题。该文本框始终显示“未找到”，而应显示用户名。注意：文本框只是一个例子。

登录页面：

     protected void login_Click(object sender, EventArgs e)
    {
        Session.RemoveAll();
        Session.Abandon();
        Session.Clear();
        string username = email.Text.ToLower().Trim();
        SqlConnection con = new SqlConnection(System.Configuration.ConfigurationManager.ConnectionStrings["myConnectionString"].ToString());
        con.Open();
        string sql = "SELECT USERNAME, PASSWORD FROM MANAGER WHERE USERNAME = @USERNAME AND PASSWORD=@PASSWORD";
        SqlCommand command = new SqlCommand(sql, con);
        command.Parameters.AddWithValue("@USERNAME", username);
        command.Parameters.AddWithValue("@PASSWORD", password.Text.Trim());
        SqlDataAdapter da = new SqlDataAdapter(command);
        DataTable dt = new DataTable();
        da.Fill(dt);
        command.ExecuteNonQuery();
        command.Dispose();
        con.Close();
        if (dt.Rows.Count > 0)
        {
            Session["manager"] = username;
            Response.Redirect("ManagerHomePage.aspx");
            Session.RemoveAll();
        }
        else
        {
            Label1.Text = "Invalid Email or Password!";
        }
    }

ManagerHomePage.aspx：受保护的void Page_Load（对象发送者，EventArgs e） {

        if(Session["manager"]!=null)
        {
            TextBox1.Text = Session["manager"].ToString();

        }
        else
        {
            TextBox1.Text = "not found";
        }

    }

Answer 1

请勿将ExecuteNonQuery用于Select命令。 ExecuteNonQuery用于Insert，Update，Delete命令。尝试使用ExecuteReader 贝娄是代码

protected void login_Click(object sender, EventArgs e)
{
    Session.RemoveAll();
    Session.Abandon();
    Session.Clear();
    string username = email.Text.ToLower().Trim();
    SqlConnection con = new SqlConnection(System.Configuration.ConfigurationManager.ConnectionStrings["myConnectionString"].ToString());
    con.Open();
    string sql = "SELECT USERNAME, PASSWORD FROM MANAGER WHERE USERNAME = @USERNAME AND PASSWORD=@PASSWORD";
    SqlCommand command = new SqlCommand(sql, con);
    command.Parameters.AddWithValue("@USERNAME", username);
    command.Parameters.AddWithValue("@PASSWORD", password.Text.Trim());
    SqlDataReader rdr=command.ExecuteReader();
    if(rdr.HasRows())
    {
        Session["manager"] = username;
        Response.Redirect("ManagerHomePage.aspx");
    }        
    else
    {
        Label1.Text = "Invalid Email or Password!";
    }
}

会话登录-会话字符串为null

1 个答案: