Error: The type 'System.Data.OleDb.OleDbDataReader' has no constructors defined

Question

I am trying to change password option with ms access database....

please help me folks....

here the code: default.aspx.cs

protected void Button1         


        

Answer 1

Problem: You try to make new instance of OleDbDataReader by calling new OleDbDataReader() instead you should create a reader using OleDbCommand.ExecuteReader().

In the following code notice use of using statement (this should ensure connection closing or reader closing for the case of OleDbDataReader).

protected void Button1_Click(object sender, EventArgs e)
{
    try
    {
        string sConnString = ConfigurationManager.ConnectionStrings["vhgroupconnection"].ConnectionString;
        using(OleDbConnection myCon = new OleDbConnection(sConnString))
        {
             myCon.Open();
             string userid = txtuserid.Text;
             string oldpass = txtoldpass.Text;
             string newPass = txtnewpass.Text;
             string conPass = txtconfirmpass.Text;

             string q = "select user_id,passwd from register where user_id = @userid and passwd = @oldpass";

             OleDbCommand cmd = new OleDbCommand(q, myCon);
             cmd.Parameters.AddWithValue("@userid", txtuserid.Text);
             cmd.Parameters.AddWithValue("@oldpass", txtoldpass.Text);

             string sUserId = string.Empty;
             string sPass = string.Empty;

             using(OleDbDataReader reader = cmd.ExecuteReader())
             {
                if(reader.Read()) //assumption: one record returned
                {           
                   sUserId = reader["user_id"].ToString();
                   sPass = reader["passwd"].ToString();

                }
             }

             if (sUserId != string.Empty && sPass != string.Empty)
             {
               if (newPass.Trim() != conPass.Trim())                   
                   lblmsg.Text = "New Password and old password does not match";
               else
               {
                    q = "UPDATE register SET passwd = @newPass WHERE user_id =@userid";
                    cmd = new OleDbCommand(q, myCon);
                    cmd.Parameters.AddWithValue("@newPass", txtnewpass.Text);
                    cmd.Parameters.AddWithValue("@userid", txtuserid.Text);                       

                    int count = cmd.ExecuteNonQuery();

                    if (count > 0)                
                       lblmsg.Text = "Password changed successfully";                
                    else                
                       lblmsg.Text = "password not changed";

               }
            }
        }
    }
    catch (Exception ex)
      {
        throw ex;
      }
}