dataset 生成 treeview
我的dataset的表里有四个字段courseid coursename chapterid chaptername
要生成一个树放到treeview里
给个递归算法~
在线等 --------------------编程问答-------------------- 我是把它写到一个类里的,希望对楼主有帮助。
using System;
using System.Data;
using OnLineExam.DataAccessLayer;
namespace OnLineExam.CommonComponent
{
/// <summary>
/// 一个通用的树状菜单类
/// </summary>
public class Tree
{
private string _treeHtml;
private DataTable _dataTable;
/// <summary>
/// 根据DataTable对象,生成一棵树
/// </summary>
/// <param name="dataTable">树中节点的数据</param>
/// <returns>树的HTML代码</returns>
public string CreateTree(DataTable dataTable)
{
this._dataTable = dataTable;
this.CreateSubTree(0);
return _treeHtml;
}
/// <summary>
/// 获取父节点编号为parentId的所有节点,并用DataTable返回
/// </summary>
/// <param name="parentId">父节点编号</param>
/// <returns>DataTable形式的所有孩子节点数据</returns>
private DataTable GetChilds(int parentId)
{
DataTable childNodes = new DataTable();
childNodes = this._dataTable.Clone();
foreach (DataRow dr in this._dataTable.Rows)
{
if (Convert.ToInt32(dr["ParentId"]) == parentId)
{
childNodes.ImportRow(dr);
}
}
return childNodes;
}
/// <summary>
/// 判断编号为nodeId的节点是否为叶子节点
/// </summary>
/// <param name="nodeId">待判断的节点编号</param>
/// <returns>是叶子节点:返回true;否则:返回false</returns>
private bool IsLeaf(int nodeId)
{
foreach (DataRow dr in this._dataTable.Rows)
if (Convert.ToInt32(dr["ParentId"]) == nodeId)
return false;
return true;
}
/// <summary>
/// 得到编号为nodeId的节点的父节点编号
/// </summary>
/// <param name="nodeId">节点编号</param>
/// <returns>父节点编号</returns>
private int GetParent(int nodeId)
{
foreach (DataRow dr in this._dataTable.Rows)
if (Convert.ToInt32(dr["NodeId"]) == nodeId)
return Convert.ToInt32(dr["ParentId"]);
return -1;
}
/// <summary>
/// 得到编号为nodeId的节点的级别,根节点为0
/// </summary>
/// <param name="nodeId">待计算的巨额电编号</param>
/// <returns>节点的级别,根节点为0</returns>
private int GetLevel(int nodeId)
{
int parentId = GetParent(nodeId);
if (parentId == 0) return 1;
else
return GetLevel(parentId) + 1; //递归
}
/// <summary>
/// 递归生成根编号为nodeId的树
/// </summary>
/// <param name="nodeId">所要生成子树的根节点</param>
private void CreateSubTree(int nodeId)
{
DataTable childNodes = this.GetChilds(nodeId); //获取根节点的所有孩子
//循环生成根节点的所有孩子对应的HTML
int childId = 0;
foreach (DataRow dr in childNodes.Rows)
{
childId = Convert.ToInt32(dr["nodeId"]);
this._treeHtml += "<div id=div_" + childId.ToString() + ">";
//根据该孩子的级别,生成一些空格,以体现层次结构
for (int i = 0; i < GetLevel(childId); i++)
this._treeHtml += " ";
//如果该孩子是叶子节点,则生成其HTML代码
if (this.IsLeaf(childId))
{
this._treeHtml += "<img src='..\\Images\\folder.gif'/><a href=" + dr["Url"] + ">" + dr["Text"] + "</a></div>";
}
//如果该孩子为中间节点,则首先构造其HTML,然后递归生成其所有孩子的HTML
else
{
this._treeHtml += "<img src='..\\Images\\folderopen.gif'/><a href=" + dr["Url"] + ">" + dr["Text"] + "</a></div>";
this.CreateSubTree(childId);//递归
}
}
}
}
} --------------------编程问答-------------------- 东西是挺好,看了会没看懂~ --------------------编程问答-------------------- 没什么复杂的,无非就是首先根据第一级(根节点)的条件,构建根节点,然后循环调用创建子节点的方法构造所有的子节点。 --------------------编程问答-------------------- 晕乎乎啊 --------------------编程问答--------------------
--------------------编程问答-------------------- ==! 没办法,做程序,不能怕辛苦,把看代码当成看小说确实很有难度。
//parentId是父节点ID,看你从哪一层开始生成tree了,生成全部就先取出根节点ID
//使用:CreateTreeViewRecursive(你的treeview控件.nodes, 数据表, 父节点ID)
private void CreateTreeViewRecursive(TreeNodeCollection nodes, DataTable dataSource, int parentId)
{
string fliter = string.Format("chapterid ={0}", parentId);
DataRow[] drArr = dataSource.Select(fliter);
TreeNode node;
foreach (DataRow dr in drArr)
{
node = new TreeNode();
nodes.Add(node);
node.Value = dr["courseid"].ToString();
node.Text = (string)dr["coursename"];
CreateTreeViewRecursive(node.ChildNodes, dataSource, (int)dr["courseid "]);
}
}
补充:.NET技术 , ASP.NET