hi, cheena try this code
private yourControl_Click()
{
BoundColumn hplarea;
hplarea = new BoundColumn();
hplarea.HeaderText = "new column";
hplarea.DataField = "new field";
hplarea.Visible = false;
SearchByAreaDataGrid.Columns.Add(hplarea);
da = new SqlDataAdapter("SELECT newfield FROM yourTable",_conStr);
Store = new DataSet();
da.Fill(Store);
DataGrid1.DataSource = store;
DataGrid1.DataBind();
}