我正在验证 C# 中的表格，但我不知道我做错了什么。 请帮我解决这个问题

Question

I'm creating a validation for form data coming from database and then comparing it with data entered in textboxes. It always executes else part whether I enter correct or incorrect data in textboxes, please help with this.

c.Uname = Text1.Value.ToString();
c.Cnic  = Text2.Value.ToString();
c.pass = Text3.Value.ToString();

SqlConnection sqlConn = new SqlConnection(@"Data Source=DESKTOP-Q4AAHCG;Initial Catalog=practise;User ID=;Password=;Trusted_Connection=True");

SqlCommand sqlComm = new SqlCommand("select Uname , Cnic, password from carregister", sqlConn);
sqlConn.Open();

SqlDataReader dr = sqlComm.ExecuteReader();

while (dr.Read())
{
    name = dr["Uname"].ToString();
    cnic = dr["Cnic"].ToString();
    passs = dr["password"].ToString();

    if (name.Equals(c.Uname) && cnic.Equals(c.Cnic) && passs.Equals(c.pass))
    {
        Session["Uname"] = Text1.Value.ToString();
        Session["cnic"] = Text2.Value.ToString();

        Response.Redirect("Carloby.aspx");
    }
    else 
    {
        Response.Redirect("wrongidpass.aspx");
    }
}

Answer 1

You are reading ALL rows of your usertable and start comparing with the first received row. If this doesn't match, you are already redirecting...

You could count only the matching rows from your database, and if that returns anything other than 1 , there is an error with username or password (or your database).

c.Uname = Text1.Value.ToString();
c.Cnic  = Text2.Value.ToString();
//you don't store plaintext passwords in your db, do you?
c.pass = hash_the_password(Text3.Value.ToString());  

SqlConnection sqlConn = new SqlConnection(@"Data Source=DESKTOP-Q4AAHCG;Initial Catalog=practise;User ID=;Password=;Trusted_Connection=True");

SqlCommand sqlComm = new SqlCommand("SELECT COUNT(*) FROM carregister WHERE uname = @uname and cnic = @cnic and password = @hashedpassword", sqlConn);
sqlComm.Parameters.Add("@uname", SqlDbType.NVarchar).Value = c.Uname;
sqlComm.Parameters.Add("@cnic", SqlDbType.NVarchar).Value = c.Cnic;
sqlComm.Parameters.Add("@hashedpassword", SqlDbType.NVarchar).Value = c.pass;
sqlConn.Open();

if (Convert.ToInt32(sqlComm.ExecuteScalar()) == 1) {
  //you have exactly one row where uname, cnic and password match the entered values
    Session["Uname"] = Text1.Value.ToString();
    Session["cnic"] = Text2.Value.ToString();

    Response.Redirect("Carloby.aspx");
}
else 
{
    //no row matched 
    //(or more than one which is an error in the database, because uname should probably be unique)
    Response.Redirect("wrongidpass.aspx");
}