Question Copy from datatable to new datatable


Aug 27, 2012
Programming Experience
Hi all,

Hoping for some pointers / advice.........

I have a winforms application that imports data from a flat file into a datatable.

I need to select certain columns from this import & use there to populate a second datatable, as well as a dataview grid.

The following is the code that I am using to import the data :-

        // Select & open file
        private void button1_Click_1(object sender, EventArgs e)
            OpenFileDialog fdlg = new OpenFileDialog();
            fdlg.Title = "Select a File to import";
            fdlg.InitialDirectory = @"c:\";
            fdlg.FileName = txtFileName.Text;
            fdlg.Filter = "Comma Seperated Values Files|*.csv";
            fdlg.FilterIndex = 1;
            fdlg.RestoreDirectory = true;
            if (fdlg.ShowDialog() == DialogResult.OK)
                txtFileName.Text = fdlg.FileName;
        // Import file into DataTable 
        private void ImportRaw()
            if (txtFileName.Text.Trim() != string.Empty)
                    // Populate the DataTable
                    DataTable dtRaw = GetDataTableRaw(txtFileName.Text);
                catch (Exception ex)
        public static DataTable GetDataTableRaw(string strFileName)
            ADODB.Connection oConn = new ADODB.Connection();
            oConn.Open("Provider=Microsoft.Jet.OleDb.4.0; Data Source = " + System.IO.Path.GetDirectoryName(strFileName) + "; Extended Properties = \"Text;HDR=YES;FMT=Delimited\";", "", "", 0);
            string strQuery = "SELECT * FROM [" + System.IO.Path.GetFileName(strFileName) + "]";
            ADODB.Recordset rs = new ADODB.Recordset();
            System.Data.OleDb.OleDbDataAdapter adapter = new System.Data.OleDb.OleDbDataAdapter();
            DataTable dtRaw = new DataTable();
            rs.Open(strQuery, "Provider=Microsoft.Jet.OleDb.4.0; Data Source = " + System.IO.Path.GetDirectoryName(strFileName) + "; Extended Properties = \"Text;HDR=YES;FMT=Delimited\";",
                ADODB.CursorTypeEnum.adOpenForwardOnly, ADODB.LockTypeEnum.adLockReadOnly, 1);
            adapter.Fill(dtRaw, rs);
            return dtRaw;

I've tried various things to select the columns I want into a new datatable & linked to a datagridview - all with no success unfortunately.
eg:- DataTable dtSelectedColumns = dtRaw.DefaultView.ToTable(false, dgcolumn1, dgcolumn2, dgcolumn3, dgcolumn4);

Any suggestions would be great.

That DataView.ToTable method requires the names of the columns in the DataTable that you want to copy. This has nothing whatsoever to do with the grid. Is 'dgcolumn1' a string variable containing the name of a column in 'dtRaw'? If not then of course it's not going to work.
Thanks for the reply - dgcolumn1 is indeed a string variable.
Turned out to be a simple error - I had part of the code relating to dtRaw in the incorrect scope (sigh).
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