Database connection issue

[WileeDarklight]

Hey all!

I'm rather new to connecting to external sources so bear with me. The error I'm getting is that "No data exists for the row/column."

the code in question:

String ConnectionString;
ConnectionString = "Provider=Microsoft.Jet.OLEDB.4.0;" + "Data Source = C:\\Users;Extended Properties =dBase IV;";
System.Data.OleDb.OleDbConnection dBaseConnection;
dBaseConnection = new System.Data.OleDb.OleDbConnection(ConnectionString);
dBaseConnection.Open();
System.Data.OleDb.OleDbCommand dBaseCommand;
dBaseCommand = new System.Data.OleDb.OleDbCommand("SELECT FPHONE FROM ADDRESS", dBaseConnection);
System.Data.OleDb.OleDbDataReader dBaseDataReader;
dBaseDataReader = dBaseCommand.ExecuteReader(CommandBehavior.SequentialAccess);

txtFaxNum.Text = dBaseDataReader.GetValue(0).ToString();


The full data source is in that format (meaning seperated with \\ ) and the coloumn name is correct and that is the name of the table. Can anyone tell me what I'm doing wrong?

[Arjay]

You need to call the OleDbDataReader.Read method before accessing the row data. Also, be sure to close the resources after you are finished with them. A 'using' block is a handy way to do this.

String connectionString = "Provider=Microsoft.Jet.OLEDB.4.0;" + "Data Source = C:\\Users;Extended Properties =dBase IV;";

using( var dBaseConnection = new OleDbConnection(connectionString) )
{
  dBaseConnection.Open();

  using( OleDbCommand dBaseCommand = new OleDbCommand("SELECT FPHONE FROM ADDRESS", dBaseConnection) )
  {
    OleDbDataReader dBaseDataReader = dBaseCommand.ExecuteReader(CommandBehavior.SequentialAccess);

    while( dBaseDataReader.Read( ) )
    {
        // retrieve the string from column 0 (NOTE: if the query returns
        // more than one record, all faxnum will be overwritten except 
        // the last one
        txtFaxNum.Text = dBaseDataReader.GetString( 0 );
    }
  }
}

[WileeDarklight]

Okay, but now it tells me the cast is invalid on this line:

txtFaxNum.Text = dBaseDataReader.GetString(0);

I can't think straight anymore, I've been staring at this program all day and I keep having to come back to this bit.

[viperbyte]

How about textbox1.txt = dBaseDataReader("whateverColum").ToString ?

[Arjay]

Okay, but now it tells me the cast is invalid on this line:

txtFaxNum.Text = dBaseDataReader.GetString(0);

I can't think straight anymore, I've been staring at this program all day and I keep having to come back to this bit.

Yeah, sorry - I use a safe data reader class that's slightly different. It should be:

txtFaxNum.Text = dBaseDataReader[ 0 ].GetString( );