Question

I have folowing code of c# in which I am making connection with access db and and using some conditions.I call a single row from db by using where clause in query.When I Logged into the page it gets data accurately.But after some time when i refresh the page it shows the folowing error

“There is No Row at position 0”
My code is is Bellow

protected void Page_Load(object sender, EventArgs e)
{
    OleDbConnection con = new OleDbConnection("Provider=Microsoft.Jet.OLEDB.4.0; Data Source=|DataDirectory|OID.mdb;Persist Security Info=False;");
    //OleDbConnection con = new OleDbConnection("Data Source=sml; User ID=sml; Password=sml; provider=OraOLEDB.Oracle");

    OleDbCommand cmd = new OleDbCommand();
    cmd.CommandText = "Select * from EMAILS WHERE EMAIL= '" + GlobalData.Email + "'";
    //cmd.CommandText = "Select * from EMAILS";
    cmd.CommandType = CommandType.Text;
    cmd.Connection = con;
    OleDbDataAdapter da = new OleDbDataAdapter(cmd);
    DataSet ds = new DataSet();
    da.Fill(ds);

    String email = ds.Tables[0].Rows[0][1].ToString();

    if (email == GlobalData.Email)
    {
        Label2.Text = GlobalData.Email;
        Label1.Text = GlobalData.Name;
        Label3.Text = GlobalData.LastName;
        Label1.Visible = false;
        Label3.Visible = false;
        Label4.Text = Label1.Text + ' ' + Label3.Text;  
    }
}

I am querying data from DB and using where cluse with Global Variable to retrive a single row

Can Any one Please tell me that how can i Remove this issue or can i loop through the DB that evry time when user login it gets data using loop and then follow the condtion

Answer 1

That means your query is not returning anything and therefore when you call this line:

String email = ds.Tables[0].Rows[0][1].ToString();

You get an exception because there’s no Row[0]

If you want to avoid that error do something like:

if (ds.Tables[0].Rows.Count>0)
{
   String email = ds.Tables[0].Rows[0][1].ToString();
   ///...
}

Don’t do select * ever in your code. Get used to list the exact columns you want to select from the table. For example:

select email_address from Emails where id= 5

Extra comment: Your query above is kind of pointless; it seems that you are trying to select an email address from a table using the same email address in the where clause. Why do you need to select it from the database if you already know the email? Judging by the variable name (GlobalData.Email) it seems that this is a predefined value…