private void Util_AddExcelSolution(TreeNode root, DB.ExcelSolution solu)
{
TreeNode soluNode = new TreeNode(solu.text);
soluNode.Name = solu.name;
soluNode.Tag = solu;
soluNode.SelectedImageKey = soluNode.ImageKey = "EXCEL";
foreach (DB.ExcelXMLLayout layout in solu.EachLayout())
{
Util_AddLayout(soluNode, layout);
}
root.Nodes.Add(soluNode);
}