TreeView的绑定

        近期遇到了TreeView的数据库绑定问题，确实是弄了我好几天，特别是多级节点的分步绑定，最開始不分步，发现所有载入页面都卡爆了，真心让人头疼。所以放出来，给须要的朋友看看，以免大家走冤枉路。

1.仅仅有一级节点的数据表绑定

部分代码：

protected void treeviewbind()
    { 
        string sqlstr=ConfigurationManager.AppSettings["constr"];
        SqlConnection con = new SqlConnection(sqlstr);
        con.Open();
        string strfac = "select * from tDepartment";
        SqlDataAdapter ada = new SqlDataAdapter(strfac,con);
        DataTable dt = new DataTable();
        ada.Fill(dt);
        string id = "Department";
        string text = "Department";
        Bind_Tv(dt, id,text);
        dt.Dispose();
        ada.Dispose();
        con.Close();

    }
    protected void Bind_Tv(DataTable dt, string id, string text)   //TreeView的递归绑定
    {
        DataView dv = new DataView(dt);//将DataTable存到DataView中，以便于筛选数据
        TreeNode tn;//建立TreeView的节点（TreeNode），以便将取出的数据加入到节点中
        foreach (DataRowView row in dv)
        {
            tn = new TreeNode();//建立一个新节点（学名叫：一个实例）
            tn.Value = row[id].ToString();//节点的Value值，一般为数据库的id值
            tn.Text = row[text].ToString();//节点的Text，节点的文本显示
            TreeView1.Nodes.Add(tn);//将该节点加入到TreeView中
        }
    }

2.多级节点分步载入绑定

相关代码：

<asp:TreeView ID="TreeView1" runat="server" ImageSet="Simple" CssClass="gridview_m"
                                                OnSelectedNodeChanged="TreeView1_SelectedNodeChanged" NodeIndent="35" ExpandDepth="0"
                                                ShowLines="True" OnTreeNodeExpanded="TreeView1_TreeNodeExpanded">
                                            </asp:TreeView>

protected void bind()   //TreeView的数据绑定
    {
        string sqlstr = ConfigurationManager.AppSettings["constr"];
        SqlConnection conn = new SqlConnection(sqlstr);
        conn.Open();

        string sqlsel = "select * from tDataSheetDirectory";
        SqlCommand cmd = new SqlCommand(sqlsel, conn);
        SqlDataAdapter sda = new SqlDataAdapter(cmd);
        DataTable dt = new DataTable();
        sda.Fill(dt);

        string id = "DataSheetDirectoryID";
        string text = "DirectoryName";
        string pid = "FatherID";

        DataView dvtop = new DataView(dt);             //加入根节点
        TreeNode tntop = new TreeNode();
        dvtop.RowFilter = "FatherID is null";
        foreach (DataRowView row in dvtop)
        {
            tntop.Value = row[id].ToString();
            tntop.Text = row[text].ToString();
            TreeView1.Nodes.Add(tntop);
        }
        sda.Dispose();
        cmd.Dispose();
        conn.Close();
        Bind_Tv(dt, tntop, tntop.Value, id, pid, text);
    }
    protected void Bind_Tv(DataTable dt, TreeNode p_Node, string pid_val, string id, string pid, string text)   //TreeView的递归绑定
    {
        DataView dv = new DataView(dt);//将DataTable存到DataView中，以便于筛选数据
        //建立TreeView的节点（TreeNode），以便将取出的数据加入到节点中
        //下面为三元运算符，假设父id为空，则为构建“父id字段 is null”的查询条件，否则构建“父id字段=父id字段值”的查询条件
        string filter = string.IsNullOrEmpty(pid_val) ? pid + " is null" : string.Format(pid + "='{0}'", pid_val);
        dv.RowFilter = filter;//利用DataView将数据进行筛选，选出同样 父id值 的数据
        foreach (DataRowView row in dv)
        {
            TreeNode tn = new TreeNode();
            tn.Value = row[id].ToString();//节点Value值
            tn.Text = row[text].ToString();//节点Text值
            p_Node.ChildNodes.Add(tn);//该节点加入到上级节点中
        }
    }

    protected void TreeView1_SelectedNodeChanged(object sender, EventArgs e)
    {
        ViewState["DataSheetState"] = 0;
        int directoryid = Convert.ToInt32(this.TreeView1.SelectedNode.Value);
        string sqlstr = ConfigurationManager.AppSettings["constr"];
        SqlConnection con1 = new SqlConnection(sqlstr);
        con1.Open();
        string strfac1 = "select * from tDataSheetDirectory where DataSheetDirectoryID='" + directoryid + "'";
        SqlCommand cmd1 = new SqlCommand(strfac1, con1);
        SqlDataReader dr1 = cmd1.ExecuteReader();
        dr1.Read();
        if (dr1.HasRows)
        {
            //Label1.Text = dr1["DirectoryName"].ToString();
        }
        dr1.Dispose();
        cmd1.Dispose();
        con1.Close();
        //ViewState["DataSheetDirectoryID"] = this.TreeView1.SelectedNode.Value;
        //GridViewBind("select * from tDataSheet where FatherDirID='" + this.TreeView1.SelectedNode.Value + "'");
        GridViewBind("select tDataSheetDirectory.*,tDataSheet.* from tDataSheetDirectory,tDataSheet where tDataSheet.FatherDirID='" + this.TreeView1.SelectedNode.Value + "' and tDataSheet.FatherDirID=tDataSheetDirectory.DataSheetDirectoryID and tDataSheetDirectory.Hidden='显示'");
        for (int i = 0; i < this.TreeView1.Nodes.Count; i++)
        {//跌迭根节点
            if (this.TreeView1.SelectedValue == this.TreeView1.Nodes[i].Value)
            {//假设选中的是根节点,就展开
                this.TreeView1.SelectedNode.Expanded = true;
            }
            else
            {//假设选中的不是根节点
                for (int j = 0; j < this.TreeView1.SelectedNode.Parent.ChildNodes.Count; j++)
                {//就让选中节点的全部同级节点收缩
                    this.TreeView1.SelectedNode.Parent.ChildNodes[j].CollapseAll();
                }
                //然后再展开选中的节点及其全部父节点
                //this.TreeView1.SelectedNode.Parent.Expanded = true;
                this.TreeView1.SelectedNode.Expanded = true;
            }
        }
    }protected void TreeView1_TreeNodeExpanded(object sender, TreeNodeEventArgs e)
    {
        string sqlstr = ConfigurationManager.AppSettings["constr"];
        SqlConnection conn = new SqlConnection(sqlstr);
        conn.Open();

        TreeNode exnode = e.Node;  //展开节点
        int fid = Convert.ToInt32(exnode.Value);   //展开节点ID

        string sqlsel = "select * from tDataSheetDirectory";
        SqlCommand cmd = new SqlCommand(sqlsel, conn);
        SqlDataAdapter sda = new SqlDataAdapter(cmd);
        DataTable dt = new DataTable();
        sda.Fill(dt);

        NodeExpand(dt, exnode, fid);
    }

    protected void NodeExpand(DataTable dt, TreeNode p_node, int pid)
    {
        int nextnodec = p_node.ChildNodes.Count;   //下级节点个数
        for (int i = 0; i < nextnodec; i++)
        {
            TreeNode tn = p_node.ChildNodes[i];
            tn.ChildNodes.Clear();
            int nodevalue = Convert.ToInt32(tn.Value);
            DataView ndv = new DataView(dt);     //获取整个表
            ndv.RowFilter = "FatherID = '" + nodevalue + "'";

            TreeNode tnn;          //下级节点
            foreach (DataRowView rown in ndv)
            {
                tnn = new TreeNode();
                tnn.Text = rown["DirectoryName"].ToString();
                tnn.Value = rown["DataSheetDirectoryID"].ToString();
                tn.ChildNodes.Add(tnn);
            }
        }
    }