Find maximum id of a table created in access data source

[vikujani]

I want to find the maximum id of Students table.
and that max id should be dispaly in a textBox1.

this is what i did.

///////////////////////////////////
 
try {
            com = new OleDbCommand("Select Max(sid) from Students", con);
            reader = com.ExecuteReader();
            while (reader.Read())
            {
 
                TextBox1.Text = reader["sid"].ToString();
                Label6.Text = "New Id Ok";
 
            }
        }
        catch(Exception ex){
            Label6.Text = ex.ToString();
        }
 
 
//////////////////////////////////

but still i got a error like this.
System.IndexOutOfRangeException: sid at System.Data.ProviderBase.FieldNameLookup.GetOrdina l(String fieldName) at System.Data.OleDb.OleDbDataReader.GetOrdinal(Strin g name) at System.Data.OleDb.OleDbDataReader.get_Item(String name) at _Default.Button4_Click(Object sender, EventArgs e) in j:\Bank2\Default.aspx.cs:line 36
Error is

can anyone Help on this??

[Subin Ninan]

Error is in reader["sid"].ToString()

use:

textBox1.Text = reader[0].ToString();
 

[Anton Zinchenko]

Use ExecuteScalar() instead of ExecuteReader().

            try {
                com = new OleDbCommand("Select Max(sid) from Students", con);
                TextBox1.Text = com.ExecuteScalar().ToString();
                Label6.Text = "New Id Ok";  
            }
            catch(Exception ex){
                Label6.Text = ex.ToString();
            }