用TreeView动态生成树

private void CreatTree()
{
Microsoft.Web.UI.WebControls.TreeNode tmpTNCs = new Microsoft.Web.UI.WebControls.TreeNode();
System.Data .DataTable FirstNodeTable=new DataTable ();

ConnSql("select ClassID, ClassName from repositoryclass ",FirstNodeTable);

System.Data .DataTable SecondNodeTable=new DataTable ();

ConnSql("select ClassID,TopicID from repository ",SecondNodeTable);

System.Data .DataView dv=new DataView ();

dv=SecondNodeTable.DefaultView;

string strID;

for(int i=0;i<FirstNodeTable.Rows.Count ;i++)
{
TreeNode newNode = new TreeNode();

newNode.Text =FirstNodeTable.Rows [i]["ClassName"].ToString ();
string Filter=FirstNodeTable.Rows[i]["ClassID"].ToString ();
newNode.ID=Filter;//C0001
newNode.ImageUrl="/NetOffice/Images/SiteImages/folder.gif";
dv.RowFilter ="ClassID='" + Filter + "'"; //"ClassID='C0001'";
foreach (DataRowView drv in dv)
{
tmpTNCs = new Microsoft.Web.UI.WebControls.TreeNode(); //定义结点
strID = drv["ClassID"].ToString();
tmpTNCs.ID = strID; //定义结点ID
tmpTNCs.Text = drv["TopicID"].ToString(); //定义结点文字
tmpTNCs.ImageUrl ="/NetOffice/Images/SiteImages/file.gif";
newNode.Nodes.Add(tmpTNCs);

}
this.TreeView800.Nodes.Add(newNode);


}
}