本文主要介紹關於的知識點，對【TreeView的綁定】和【unity TreeView】有興趣的朋友可以看下由【我本良人】投稿的技術文章，希望該技術和經驗能幫到你解決你所遇的【asp.net】相關技術問題。

unity TreeView

??????? 最近遇到了TreeView的數據庫綁定問題，確實是弄了我好幾天，特別是多級節點的分步綁定，最開始不分步，發現全部加載頁面都卡爆了，真心讓人頭疼。所以放出來，給需要的朋友看看，以免大家走冤枉路。

1.只有一級節點的數據表綁定

部分代碼：

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的遞歸綁定
    {
        DataView dv = new DataView(dt);//將DataTable存到DataView中，以便於篩選數據
        TreeNode tn;//建立TreeView的節點（TreeNode），以便將取出的數據添加到節點中
        foreach (DataRowView row in dv)
        {
            tn = new TreeNode();//建立一個新節點（學名叫：一個實例）
            tn.Value = row[id].ToString();//節點的Value值，一般為數據庫的id值
            tn.Text = row[text].ToString();//節點的Text，節點的文本顯示
            TreeView1.Nodes.Add(tn);//將該節點加入到TreeView中
        }
    }

2.多級節點分步加載綁定

protected void bind()   //TreeView的數據綁定
    {
        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);             //添加根節點
        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的遞歸綁定
    {
        DataView dv = new DataView(dt);//將DataTable存到DataView中，以便於篩選數據
        //建立TreeView的節點（TreeNode），以便將取出的數據添加到節點中
        //以下為三元運算符，如果父id為空，則為構建“父id字段 is null”的查詢條件，否則構建“父id字段=父id字段值”的查詢條件
        string filter = string.IsNullOrEmpty(pid_val) ? pid + " is null" : string.Format(pid + "='{0}'", pid_val);
        dv.RowFilter = filter;//利用DataView將數據進行篩選，選出相同 父id值 的數據
        foreach (DataRowView row in dv)
        {
            TreeNode tn = new TreeNode();
            tn.Value = row[id].ToString();//節點Value值
            tn.Text = row[text].ToString();//節點Text值
            p_Node.ChildNodes.Add(tn);//該節點加入到上級節點中
        }
    }

    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='顯示'");
        for (int i = 0; i < this.TreeView1.Nodes.Count; i++)
        {//跌迭根節點
            if (this.TreeView1.SelectedValue == this.TreeView1.Nodes[i].Value)
            {//如果選中的是根節點,就展開
                this.TreeView1.SelectedNode.Expanded = true;
            }
            else
            {//如果選中的不是根節點
                for (int j = 0; j < this.TreeView1.SelectedNode.Parent.ChildNodes.Count; j++)
                {//就讓選中節點的所有同級節點收縮
                    this.TreeView1.SelectedNode.Parent.ChildNodes[j].CollapseAll();
                }
                //然后再展開選中的節點及其所有父節點
                //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;  //展開節點
        int fid = Convert.ToInt32(exnode.Value);   //展開節點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;   //下級節點個數
        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);     //獲取整個表
            ndv.RowFilter = "FatherID = '" + nodevalue + "'";

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

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