how to open xls file in browser

private void btnBrowse_Click(object sender, EventArgs e)
        {
            ofBrowse.ShowDialog();
        }
        private void ofBrowse_FileOk(object sender, CancelEventArgs e)
        {
            txtFile.Text = ofBrowse.FileName;
        }

if (File.Exists(txtFile.Text))
                {
                    if (txtSheetName.Text.Trim() == "")
                    {
                        MessageBox.Show("Please enter Sheet Name", "Sheet Name Required", MessageBoxButtons.OK, MessageBoxIcon.Information);
                        txtSheetName.Select();
                        txtSheetName.Focus();
                        return;
                    }
                    ds = new DataSet();
                    Data.Fill(ds);
                    ddlParameter.Items.Clear();
                    for (int i = 0; i < ds.Tables[0].Rows.Count; i++)
                    {
                        if (ds.Tables[0].Rows[i][1].ToString().Trim() != "")
                            ddlParameter.Items.Add(ds.Tables[0].Rows[i][1].ToString().Trim());
                        if (ddlParameter.Items.Count > 0)
                            ddlParameter.SelectedIndex = 0;
                    }