如下图所示：
该控件为无限级扩展的，只需要指定其子节点字段名(默认为ID)，父节点字段名(默认为parentID)，以及第一层父节点的值即可(默认为0)。
1.首先定义常量
protected
const
string
strT
=
"
├
"
;
protected
const
string
strL
=
"
└
"
;
protected
const
string
strI
=
"
│
"
;
protected
DataTable tempTable;
protected
int
lay
=
0
;
//
节点层数
protected
int
level
=
0
;
//
DropDownList顺序
2.添加属性
[Category( " 数据 " ),Description( " 第一层父节点的值 " )] public int FirstParentValue { get { object obj = ViewState[ " FirstParentValue " ]; return ((obj == null ) ? 0 :( int )obj); } set { ViewState[ " FirstParentValue " ] = value; } } [Category( " 数据 " ),Description( " 子字段名 " )] public string ChildField { get { object obj = ViewState[ " ChildField " ]; return ((obj == null ) ? " ID " :( string )obj); } set { ViewState[ " ChildField " ] = value; } } [Category( " 数据 " ),Description( " 父字段名 " )] public string ParentField { get { object obj = ViewState[ " ParentField " ]; return ((obj == null ) ? " parentID " :( string )obj); } set { ViewState[ " ParentField " ] = value; } } [Category( " 数据 " ),Description( " 显示文本字段名 " )] public string ShowText { get { object obj = ViewState[ " ShowText " ]; return ((obj == null ) ? " name " :( string )obj); } set { ViewState[ " ShowText " ] = value; } }
3.计算当前节点所在的层以及是否为子节点，是否有兄弟节点等函数，用于生成树形
/// <summary> /// 递归算出指定ID所在树中的层数 /// </summary> /// <param name="treeTable"></param> /// <param name="ID"> 节点ID </param> private void FindLay(DataTable treeTable, int ID) { for ( int i = 0 ;i < treeTable.Rows.Count;i ++ ) { if (ID == int .Parse(treeTable.Rows[i][ this .ChildField].ToString())) { int parentID = int .Parse(treeTable.Rows[i][ this .ParentField].ToString()); // 如果父节点不是根节点,递归 if (parentID != 0 ) { lay ++ ; FindLay(treeTable, int .Parse(treeTable.Rows[i][ this .ParentField].ToString())); } } } } /// <summary> /// 判断是否有子接点 /// </summary> /// <param name="dt"></param> /// <param name="ID"> 当前节点的ID </param> /// <returns></returns> private bool IsExistChildNodes(DataTable dt, string ID) { bool flag = false ; if (ID == null ) return flag; for ( int i = 0 ;i < dt.Rows.Count;i ++ ) { if (dt.Rows[i][ this .ParentField].ToString() == ID) { flag = true ; return flag; } else { flag = false ; } } return flag; } /// <summary> /// 判断是否有兄弟节点 /// </summary> /// <param name="dt"></param> /// <param name="ID"> 当前节点的ID </param> /// <returns></returns> private bool IsBorthorNodes(DataTable dt, string ID) { bool flag = false ; if (ID == null ) return flag; for ( int i = 0 ;i < dt.Rows.Count;i ++ ) { if (dt.Rows[i][ this .ChildField].ToString() == ID && i < dt.Rows.Count - 1 ) { if (dt.Rows[i][ this .ParentField].ToString() == dt.Rows[i + 1 ][ this .ParentField].ToString()) { flag = true ; return flag; } else { flag = false ; return flag; } } } return flag; } /// <summary> /// 判断当前节点是否为子节点 /// </summary> /// <param name="dt"></param> /// <param name="ID"></param> /// <returns></returns> private bool IsChildNode(DataTable dt, string ID) { bool flag = false ; if (ID == null ) return flag; for ( int i = 0 ;i < dt.Rows.Count;i ++ ) { if (dt.Rows[i][ this .ChildField].ToString() == ID) { if (dt.Rows[i][ this .ParentField].ToString() == " 0 " ) { flag = false ; return flag; } else { flag = true ; return flag; } } } return flag; }
4.递归生成树形
/// <summary> /// 数据添加并生成树形 /// </summary> /// <param name="dt"></param> /// <param name="ID"></param> private void BindData(DataTable dt, string ID) { DataRow[] dr; dr = dt.Select( this .ParentField + " = " + ID, this .ChildField + " ASC " ); for ( int x = 0 ;x < dr.Length;x ++ ) { string str = "" ; lay = 0 ; this .FindLay(dt, int .Parse(dr[x][ this .ChildField].ToString())); if ( this .IsChildNode(dt,dr[x][this.ChildField ].ToString()) == true ) { for ( int i = 0 ;i < lay;i ++ ) { str += strI; } if ( this .IsBorthorNodes(dt,dr[x][ " id " ].ToString()) == true ) { this .Items.Insert(level, new ListItem(str + strT + dr[x][this.ShowText ].ToString(),dr[x][this.ChildField ].ToString())); } else { this .Items.Insert(level, new ListItem(str + strL + dr[x][this.ShowText ].ToString(),dr[x][this.ChildField ].ToString())); } } else { this .Items.Insert(level, new ListItem(str + dr[x][this.ShowText ].ToString(),dr[x][this.ChildField ].ToString())); } level += 1 ; this .BindData(dt,dr[x][ this .ChildField].ToString()); // 递归生成树 } }
5.绑定数据
/// <summary> /// 绑定数据 /// </summary> /// <param name="dt"> 数据源DataTable </param> public void BindListData(DataTable dt) { tempTable = dt.Clone(); this .BindData(dt, this .FirstParentValue.ToString()); }
使用的时候调用该函数进行数据绑定！
在ASP.NET中实现这个真费劲，在Silverlight中实现就方便多了。
