Database connection C#

Question

I have a question according to this code. VisualStudio shows no errors or warnings but when I run it, the result is only the exceptionerror ("Something went wrong."). This is how I have always done it before but somehow always worked except for now. Am I missing a simple thing?

        protected void Page_Load(object sender, EventArgs e)
    {
        // Connect
        OleDbConnection conn = new OleDbConnection();
        conn.ConnectionString = @"Provider=Microsoft.Jet.OLEDB.4.0;Data Source='C:\Users\royva\documents\visual studio 2013\Projects\CookieMultiView\CookieMultiView\App_Data\Databank.mdb';Persist Security Info=True";
        // Execute
        OleDbCommand cmd = new OleDbCommand();
        cmd.Connection = conn;
        cmd.CommandText = "SELECT * FROM teachers = ?";// + Request.QueryString["id"];
        lbl.Text = "";

        cmd.Parameters.AddWithValue("id",Request.QueryString["id"]);


        // Read
        try
        {
           conn.Open();
           OleDbDataReader reader = cmd.ExecuteReader();
           while (reader.Read())
           {
               lbl.Text = reader["teacherid"].ToString();
           }
        }
        catch (Exception ex)
        {
            //lbl.Text = ex.StackTrace;                
            lbl.Text = "Something went wrong.";
        }
        finally
        {
            conn.Close();
        }

Remove lbl.Text = "Something went wrong."; and then put a break point on lbl.Text = ex.StackTrace; and step through it. Also you're adding a param id but it's not in your select query — Izzy
– Izzy, Commented Jun 2, 2016 at 8:11
Check your commandText i think it should be something like that: cmd.CommandText = "SELECT * FROM teachers WHERE id = ?" — Bambuk
– Bambuk, Commented Jun 2, 2016 at 8:12
Put a breakpoint at lbl.Text = "Something went wrong."; line and see what is the actual exception. As of now, it can be any of the hundred issues. — jitendragarg
– jitendragarg, Commented Jun 2, 2016 at 8:15
I've changed the commandtext and its sadly still not fixed. Also i've used the breakpoint and got 3 exceptions, access to patch 'c/blabla/temporary ASP.NET Files' is denied. "Invalid file name for file monitoring" "no value given for one or more required parameters" — Roy van der Plas
– Roy van der Plas, Commented Jun 2, 2016 at 8:50

Ruban J · Accepted Answer · 2016-06-02 08:55:06Z

1

For Detailed info of the Exception,

catch (Exception ex)
 {
   //Either you can write log or display in label
   lbl.Text = ex.Message;
 }

Also check the folder access rights for

Data Source='C:\Users\royva\documents\visual studio 2013\Projects\CookieMultiView\CookieMultiView\App_Data\Databank.mdb'

Programmatically to check for specific files use File.Exists(path), which will return a boolean indicating whether the file at path exists.

And validate if the connection has been established or not.

answered Jun 2, 2016 at 8:55

Ruban J

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3 Comments

Roy van der Plas Over a year ago

It's a local database and the database is put there via visual studio's. The error i get with your tip of ex.message is "No value given for one or more required parameters." This will help me out! Thanks :)

Roy van der Plas Over a year ago

It was indeed the connection, somehow the database was on read-only. Got it working now! Cheers!

Ruban J Over a year ago

Good to hear @RoyvanderPlas :)

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