TreePrinter.cs source code in C# .NET

                        Code:
                         / 4.0 / 4.0 / untmp / DEVDIV_TFS / Dev10 / Releases / RTMRel / ndp / fx / src / DataEntity / System / Data / Common / Utils / TreePrinter.cs / 1305376 / TreePrinter.cs
                        
                        
                            //---------------------------------------------------------------------- 
// 
//      Copyright (c) Microsoft Corporation.  All rights reserved.
// 
// 
// @owner  [....]
//--------------------------------------------------------------------- 
 
using System;
using System.Collections.Generic; 
using System.Diagnostics;
using System.Globalization;
using System.Text;
 
namespace System.Data.Common.Utils
{ 
    ///  
    /// Represents a node in a hierarchical collection of information strings.
    /// Intended as a common way mechanism to represent tree structures for debugging (using the TreePrinter class). 
    /// A node consists of a string (represented as a StringBuilder), its collection of child nodes, and an optional Tag value.
    /// 
    internal class TreeNode
    { 
        private StringBuilder _text;
        private List _children = new List(); 
        private int _position; 

        // Default constructor 
        internal TreeNode()
        {
            _text = new StringBuilder();
        } 

        ///  
        /// Constructs a new TreeNode with the specified text, tag value and child nodes 
        /// 
        /// The initial value of the new node's text 
        /// An optional list of initial child nodes
        internal TreeNode(string text, params TreeNode[] children)
        {
            if (string.IsNullOrEmpty(text)) 
            {
                _text = new StringBuilder(); 
            } 
            else
            { 
                _text = new StringBuilder(text);
            }

            if (children != null) 
            {
                _children.AddRange(children); 
            } 
        }
 
        // IEnumerable convenience constructors
        internal TreeNode(string text, List children)
            : this(text)
        { 
            if (children != null)
            { 
                _children.AddRange(children); 
            }
        } 

        // 'public' properties

        ///  
        /// The current text of this node.
        ///  
        internal StringBuilder Text { get { return _text; } } 

        ///  
        /// The collection of child nodes for this node, which may be empty.
        /// 
        internal IList Children { get { return _children; } }
 
        // Used only by the TreePrinter when generating the output string
        internal int Position { get { return _position; } set { _position = value; } } 
    } 

    ///  
    /// Generates a formatted string from a hierarchy of tree nodes. Derived types may override
    /// the PreProcess, Before/AfterAppend, Print, PrintNode and PrintChildren methods to add
    /// specific functionality at particular points in process of building the string.
    ///  
    internal abstract class TreePrinter
    { 
        #region Private Instance Members 

        private List _scopes = new List(); 
        private bool _showLines = true;
        private char _horizontals = '_';
        private char _verticals = '|';
 
        #endregion
 
        #region 'Public' API 

        ///  
        /// Entry point method for the TreePrinter
        /// 
        /// The TreeNode instance that is the root of the tree to be printed
        /// A string representation of the specified tree 
        internal virtual string Print(TreeNode node)
        { 
             this.PreProcess(node); 

            StringBuilder text = new StringBuilder(); 
            PrintNode(text, node);
            return text.ToString();
        }
 
        #endregion
 
        #region 'Protected' API 

        // 'protected' constructor 
        internal TreePrinter() { }

        // 'protected' API that may be overriden to customize printing
 
        /// 
        /// Called once on the root of the tree before printing begins 
        ///  
        /// The TreeNode that is the root of the tree
        internal virtual void PreProcess(TreeNode node) { } 

        /// 
        /// Called once for every node after indentation, connecting lines and the node's text value
        /// have been added to the output but before the line suffix (if any) has been added. 
        /// 
        /// The current node 
        /// The StringBuilder into which the tree is being printed 
        internal virtual void AfterAppend(TreeNode node, StringBuilder text) { }
 
        /// 
        /// Called once for every node immediately after the line prefix (if any) and appropriate
        /// indentation and connecting lines have been added to the output but before the node's
        /// text value has been added. 
        /// 
        /// The current node 
        /// The StringBuilder into which the tree is being printed 
        internal virtual void BeforeAppend(TreeNode node, StringBuilder text) { }
 
        /// 
        /// The recursive step of the printing process, called once for each TreeNode in the tree
        /// 
        /// The StringBuilder into which the tree is being printed 
        /// The current node that should be printed to the StringBuilder
        internal virtual void PrintNode(StringBuilder text, TreeNode node) 
        { 
            IndentLine(text);
 
            this.BeforeAppend(node, text);
            text.Append(node.Text.ToString());
            this.AfterAppend(node, text);
 
            PrintChildren(text, node);
        } 
 
        /// 
        /// Called to recursively visit the child nodes of the current TreeNode. 
        /// 
        /// The StringBuilder into which the tree is being printed
        /// The current node
        internal virtual void PrintChildren(StringBuilder text, TreeNode node) 
        {
            _scopes.Add(node); 
            node.Position = 0; 
            foreach (TreeNode childNode in node.Children)
            { 
                text.AppendLine();
                node.Position++;
                PrintNode(text, childNode);
            } 

            _scopes.RemoveAt(_scopes.Count - 1); 
        } 

        #endregion 

        #region Private Implementation

        private void IndentLine(StringBuilder text) 
        {
            int idx = 0; 
            for (int scopeIdx = 0; scopeIdx < _scopes.Count; scopeIdx++) 
            {
                TreeNode parentScope = _scopes[scopeIdx]; 
                if (!_showLines || (parentScope.Position == parentScope.Children.Count && scopeIdx != _scopes.Count - 1))
                {
                    text.Append(' ');
                } 
                else
                { 
                    text.Append(_verticals); 
                }
 
                idx++;
                if (_scopes.Count == idx && _showLines)
                {
                    text.Append(_horizontals); 
                }
                else 
                { 
                    text.Append(' ');
                } 
            }
        }

        #endregion 
    }
} 

// File provided for Reference Use Only by Microsoft Corporation (c) 2007.
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TreePrinter.cs source code in C# .NET

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