Treeview查找节点方法

2009年4月23日星期四

Treeview查找节点方法

写asp.net时,经常操作 TreeView 控件。经常需要找到他的某一个节点,


操作方法是:



    /// <summary>
    /// 获取 指定value值的节点
    /// </summary>
    /// <param name="tnParent">指定节点</param>
    /// <param name="strValue">value值</param>
    /// <returns></returns>
    private TreeNode FindNodeByValue(TreeNode tnParent, string strValue)
    {


        if (tnParent == null) return null;


        if (tnParent.Value  == strValue) return tnParent;



        TreeNode tnRet = null;


        foreach (TreeNode tn in tnParent.ChildNodes)
        {


            tnRet = FindNodeByValue(tn, strValue);


            if (tnRet != null) break;


        }


        return tnRet;


    }




    /// <summary>
    /// 获取 指定Text值的节点
    /// </summary>
    /// <param name="tnParent">指定节点</param>
    /// <param name="strValue">Text值</param>
    /// <returns></returns>
    private TreeNode FindNodeByText(TreeNode tnParent, string strText)
    {


        if (tnParent == null) return null;


        if (tnParent.Text == strText) return tnParent;


 


        TreeNode tnRet = null;


        foreach (TreeNode tn in tnParent.ChildNodes)
        {


            tnRet = FindNodeByText(tn, strText);


            if (tnRet != null) break;


        }


        return tnRet;


    }


 


 


调用方法:


 



 



        TreeNode tnRet = null;


        foreach( TreeNode tn in TreeView1.Nodes )


        {


            tnRet = FindNodeByValue(tn, "202020");


            if( tnRet != null ) break;


        }


 


        tnRet.Text = "更改后的Text";


 


参考如下:


 


 


 


 




Treeview查找节点算法


TreeView查找某一节点,通常有两种方法,一种是递归的,一种不是递归,但都是深度优先算法。其中,非递归方法效率高些,而递归算法要简洁一些。


 


第一种,递归算法,代码如下:


    private TreeNode FindNode( TreeNode tnParent, string strValue )


    {


        if( tnParent == null ) return null;


        if( tnParent.Text == strValue ) return tnParent;


 


        TreeNode tnRet = null;


        foreach( TreeNode tn in tnParent.Nodes )


        {


            tnRet = FindNode( tn, strValue );


            if( tnRet != null ) break;


        }


        return tnRet;


    }


 


第二种,非递归算法,代码如下:


    private TreeNode FindNode( TreeNode  tnParent, string strValue )


    {


        if( tnParent == null ) return null;


 


        if( tnParent.Text == strValue ) return tnParent;


        else if( tnParent.Nodes.Count == 0 ) return null;


 


        TreeNode tnCurrent, tnCurrentPar;


 


        //Init node


        tnCurrentPar = tnParent;


        tnCurrent = tnCurrentPar.FirstNode;


 


        while( tnCurrent != null && tnCurrent != tnParent )


        {


            while( tnCurrent != null )


            {


                if( tnCurrent.Text == strValue ) return tnCurrent;


                else if( tnCurrent.Nodes.Count > 0 )


                {


                    //Go into the deepest node in current sub-path


                    tnCurrentPar = tnCurrent;


                    tnCurrent = tnCurrent.FirstNode;


                }


                else if( tnCurrent != tnCurrentPar.LastNode )


                {


                    //Goto next sible node


                    tnCurrent = tnCurrent.NextNode;


                }


                else


                    break;


            }


               


            //Go back to parent node till its has next sible node


            while( tnCurrent != tnParent && tnCurrent == tnCurrentPar.LastNode )


            {


                tnCurrent = tnCurrentPar;


                tnCurrentPar = tnCurrentPar.Parent;


            }


 


            //Goto next sible node


            if( tnCurrent != tnParent )


                tnCurrent = tnCurrent.NextNode;


        }


        return null;


    }


 


       程序调用,如下:


        TreeNode tnRet = null;


        foreach( TreeNode tn in yourTreeView.Nodes )


        {


            tnRet =  FindNode( tn, yourValue );


            if( tnRet != null ) break;


        }


 代码转换:


Public Function findnode(ByVal parentnode As TreeNode, ByVal str As String) As TreeNode
        Dim thenode As New TreeNode
        If (parentnode Is Nothing) Then
            Return Nothing
        End If


        If (parentnode.Text = str) Then
            Return parentnode
        End If


        Dim node As New TreeNode
        For Each node In parentnode.Nodes
            thenode = findnode(node, str)
            If thenode.Text = str Then
                Exit For
            End If
        Next
        Return thenode
    End Function


0 评论:

发表评论