private EO.Web.Grid m_Grid;

protected void Page_Load(object sender, EventArgs e)
{
    m_Grid = (EO.Web.Grid)FileExplorer1.FindControl("FileGrid");
    m_Grid.ColumnSort += Grid_ColumnSort;
}

protected override void OnPreRenderComplete(EventArgs e)
{
    base.OnPreRenderComplete(e);

    if (!IsPostBack)
        FilterGrid();
}

private void Grid_ColumnSort(object sender, EO.Web.GridColumnEventArgs e)
{
    FilterGrid();
}

private void FilterGrid()
{
    IList dataSource = (IList)m_Grid.DataSource;
    ArrayList filteredDataSource = new ArrayList();
    for (int i = 0; i < dataSource.Count; i++)
    {
        //Get the data source item and its full path
        object dataItem = dataSource[i];
        string[] pathInfo = dataItem.GetType().GetProperty("PathInfo").GetValue(dataItem, new object[] { }).ToString().Split('|');
        string fullPath = Server.MapPath(pathInfo[0]);

        //If the file does not have Hidden attribute,
        //then add it to filteredDataSource
        System.IO.FileInfo fileInfo = new System.IO.FileInfo(fullPath);
        if (((int)fileInfo.Attributes & (int)System.IO.FileAttributes.Hidden) == 0)
            filteredDataSource.Add(dataItem);
    }

    //Repopulate the Grid with the filteredDataSource
    m_Grid.DataSource = filteredDataSource;
    m_Grid.DataBind();
}