一起谈.NET技术，Silverlight中使用递归构造关系图-阿里云开发者社区

　　这两天遇到一个问题，项目中需要在silverlight中使用连接图的方式来显示任务之间的关系，总体有父子和平行两种，昨天在改同事的代码，一直出问题，索性晚上写了一下实现方法。

　　需求

　　有一个List对象中存了若干个Task，这些Task对象通过ParentID属性进行关联，现在要求将这个List中的任务使用图的方式形成如父子关系和平行关系的图示例如下图：

　　实现方法思考

　　刚开始接到这个任务我就想着递归应该可以搞定了，但是仔细考虑才发现每个任务的子任务需要在一定区域内才行，需要计算子级和子级之间的距离，如果使用递归，例如上图的元素“12”的位置就没有办法很好确定了。

　　我决定将途中的节点抽象为一个类，这个类至少应该含有上边界top,左边届left及节点的名称等属性，然后从这个List对象中构造出每个节点的属性。

　　实现步骤

　　1，首先我们为图模拟一个数据源，注意其中的任务是通过ParentID关联的。

代码

private static List < Task > listTask;
         public MainPage()
        {
            InitializeComponent();
            listTask = new List < Task > ();
            listTask.Add( new Task() { ID = 1 , ParentID = 0 , Name = " 1 " });
            listTask.Add( new Task() { ID = 2 , ParentID = 1 , Name = " 11 " });
            listTask.Add( new Task() { ID = 3 , ParentID = 1 , Name = " 12 " });
            listTask.Add( new Task() { ID = 4 , ParentID = 2 , Name = " 21 " });
            listTask.Add( new Task() { ID = 5 , ParentID = 2 , Name = " 22 " });
            listTask.Add( new Task() { ID = 6 , ParentID = 3 , Name = " 31 " });
            listTask.Add( new Task() { ID = 7 , ParentID = 3 , Name = " 32 " });
            listTask.Add( new Task() { ID = 8 , ParentID = 3 , Name = " 33 " });
            listTask.Add( new Task() { ID = 9 , ParentID = 4 , Name = " 42 " });
            listTask.Add( new Task() { ID = 10 , ParentID = 4 , Name = " 42 " });
            listTask.Add( new Task() { ID = 11 , ParentID = 3 , Name = " 34 " });
            listTask.Add( new Task() { ID = 12 , ParentID = 5 , Name = " 51 " });
            listTask.Add( new Task() { ID = 13 , ParentID = 8 , Name = " 81 " });
             this .Loaded += new RoutedEventHandler(MainPage_Loaded);
        }

　　2，然后我们为要生成的图中节点构造一个类。

代码

class TaskPro
        {
             public Task task { set ; get ; }
             public double top { set ; get ; }
             public double left { set ; get ; }
             public int index { set ; get ; } // 这是为了找到节点在某层的位置来计算left
        }

　　3，使用递归将List中的数据做初步整理，存入一个List<TaskPro>中，此时节点对象将具备top属性，上边距搞定。

代码

void AddMethod(Task task)
        {
             if (task.ParentID == 0 )
            {
                listOfTaskPro.Add( new TaskPro() { task = task, top = 0 , index = 0 , left = 0   });
            }
             else
            {
                var t = listTask.Where(m => m.ID == task.ParentID).FirstOrDefault();
                var tpro = listOfTaskPro.Where(m => m.task.ID == t.ID).FirstOrDefault();
                listOfTaskPro.Add( new TaskPro() { task = task, index = 0 , top = tpro.top + 50 , left = 0 });
            }
             foreach (Task t in listTask.Where(m => m.ParentID == task.ID).ToList())
            {
                AddMethod(t);
            }
        }

　　4，我们需要算出节点对象的左边距，在第3步中我没能找到方法，于是想到利用每一级的元素个数来计算每个节点的位置，然后使用每一级的平均节点距离*节点的索引便可得到left。

代码

// 构造各层及数量
             foreach (TaskPro t in listOfTaskPro)
            {
                 bool IsExist = false ;
                 foreach (TaskCount tc in listTopAndTasks)
                {
                    IsExist = tc.Top == t.top ? true : false ;
                }
                 if ( ! IsExist)
                {
                    listTopAndTasks.Add( new TaskCount() { Top = t.top, Tasks = new List < Task > () });
                }
                var topAndTasks = listTopAndTasks.Where(m => m.Top == t.top).FirstOrDefault();
                topAndTasks.Tasks.Add(t.task);
            }
             // 构造index
             foreach (TaskPro t in listOfTaskPro)
            {
                 for ( int i = 0 ; i < listTopAndTasks.Count; i ++ )
                {
                     for ( int j = 0 ; j < listTopAndTasks[i].Tasks.Count; j ++ )
                    {
                         if (listTopAndTasks[i].Tasks[j].ID == t.task.ID)
                        {
                            t.index = j + 1 ;
                        }
                    }
                }
            }
             // 构造left
             for ( int i = 0 ; i < listOfTaskPro.Count; i ++ )
            {
                 if (listOfTaskPro[i].task.ParentID == 0 )
                {
                    listOfTaskPro[i].left = this .canvas1.Width / 2 ;
                }
                 else
                {
                    var childCount = listOfTaskPro.Where(m => m.task.ParentID == listOfTaskPro[i].task.ParentID).Count();
                    var parentLeft = listOfTaskPro.Where(m => m.task.ID == listOfTaskPro[i].task.ParentID).FirstOrDefault().left;
                    var perLength = parentLeft * 1.5 / (childCount + 1 );
                    listOfTaskPro[i].left = listOfTaskPro[i].index * perLength;
                }
            }

　　5，至此，节点对象已经具备了left,top属性，我们只需要找到每个节点的父节点即可将两个几点的坐标确定，进而进行划线的操作了。

代码

foreach (TaskPro t in listOfTaskPro)
            {
                AddBtn(t.task.Name, t.left, t.top);
                 if (t.task.ParentID != 0 )
                {
                    TaskPro tp = listOfTaskPro.Where(m => m.task.ID == t.task.ParentID).FirstOrDefault();
                    AddLine(tp.left + buttonWidth / 2 , tp.top + buttonHeight, t.left + buttonWidth / 2 , t.top);
                }
            }

　　6，添加按钮及划线的方法。

代码

#region 添加按钮及线条
         double buttonHeight = 20 ;
         double buttonWidth = 50 ;

         void AddBtn( string content, double left, double top)
        {
            Button btn = new Button();
            btn.Content = content;
            btn.Width = buttonWidth;
            btn.Height = buttonHeight;
             this .canvas1.Children.Add(btn);
            Canvas.SetLeft(btn, left);
            Canvas.SetTop(btn, top);
        }

// 画线方法，只需要有起始亮点的坐标即可

         void AddLine( double startLeft, double startTop, double endLeft, double endTop)
        {
            Path p = new Path();
            LineGeometry geometry = new LineGeometry();
            SolidColorBrush brush = new SolidColorBrush();
            brush.Color = Colors.Black;
            geometry.StartPoint = new Point(startLeft, startTop);
            geometry.EndPoint = new Point(endLeft, endTop);
            p.Data = geometry;
            p.Stroke = brush;
            p.StrokeThickness = 1 ;
            canvas1.Children.Add(p);
        }
         #endregion

　　运行一下，如上图。之前没有使用递归的方法是只有这样的。

代码

using System;
using System.Collections.Generic;
using System.Linq;
using System.Net;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Animation;
using System.Windows.Shapes;

namespace SilverlightApplication2
{
     public class Task
    {
         public int ID { set ; get ; }
         public int ParentID { set ; get ; }
         public string Name { set ; get ; }
    }
     public partial class MainPage : UserControl
    {
         private static List < Task > listTask;
         public MainPage()
        {
            InitializeComponent();
            listTask = new List < Task > ();
            listTask.Add( new Task() { ID = 1 , ParentID = 0 , Name = " 1 " });
            listTask.Add( new Task() { ID = 2 , ParentID = 1 , Name = " 11 " });
            listTask.Add( new Task() { ID = 3 , ParentID = 1 , Name = " 12 " });
            listTask.Add( new Task() { ID = 4 , ParentID = 2 , Name = " 21 " });
            listTask.Add( new Task() { ID = 5 , ParentID = 2 , Name = " 22 " });
            listTask.Add( new Task() { ID = 6 , ParentID = 3 , Name = " 31 " });
            listTask.Add( new Task() { ID = 7 , ParentID = 3 , Name = " 32 " });
            listTask.Add( new Task() { ID = 8 , ParentID = 3 , Name = " 33 " });
            listTask.Add( new Task() { ID = 9 , ParentID = 4 , Name = " 42 " });
            listTask.Add( new Task() { ID = 10 , ParentID = 4 , Name = " 42 " });
            listTask.Add( new Task() { ID = 11 , ParentID = 3 , Name = " 34 " });
            listTask.Add( new Task() { ID = 12 , ParentID = 5 , Name = " 51 " });
            listTask.Add( new Task() { ID = 13 , ParentID = 8 , Name = " 81 " });
             this .Loaded += new RoutedEventHandler(MainPage_Loaded);
        }
         void MainPage_Loaded( object sender, RoutedEventArgs e)
        {
            AddAll();
        }
         class TaskPro
        {
             public Task task { set ; get ; }
             public double top { set ; get ; }
             public double left { set ; get ; }
             public int index { set ; get ; }
        }
         class TaskCount
        {
             public double Top { set ; get ; }
             public List < Task > Tasks { set ; get ; }
        }
         static List < TaskPro > listTaskPro = new List < TaskPro > ();
         static List < TaskCount > listTopAndTasks = new List < TaskCount > ();
         void AddAll()
        {
             foreach (Task t in listTask)
            {
                 if (t.ParentID == 0 )
                {
                    listTaskPro.Add( new TaskPro() { task = t, index = 1 , left = this .canvas1.Width / 2 , top = 0 });
                }
                 else
                {
                     for ( int i = 0 ;i < listTaskPro.Count;i ++ )
                    {
                         if (t.ParentID == listTaskPro[i].task.ID)
                        {
                            listTaskPro.Add( new TaskPro() { task = t, top = listTaskPro[i].top + 80 , index = 0 , left = 0 });
                        }
                    }
                }
            }

             #region 汇总层及层内的元素个数
             foreach (TaskPro t in listTaskPro)
            {
                 bool IsExist = false ;
                 foreach (TaskCount tc in listTopAndTasks)
                {
                     if (tc.Top == t.top)
                    {
                        IsExist = true ;
                    }
                }
                 if ( ! IsExist)
                {
                    listTopAndTasks.Add( new TaskCount() { Top = t.top, Tasks = new List < Task > () });
                }
                var topAndTasks = listTopAndTasks.Where(m => m.Top == t.top).FirstOrDefault();
                topAndTasks.Tasks.Add(t.task);
            }
             #endregion

             foreach (TaskPro t in listTaskPro)
            {
                 for ( int i = 0 ; i < listTopAndTasks.Count;i ++ )
                {
                     for ( int j = 0 ; j < listTopAndTasks[i].Tasks.Count;j ++ )
                    {
                         if (listTopAndTasks[i].Tasks[j].ID == t.task.ID)
                        {
                            t.index = j + 1 ;
                        }
                    }
                }
            }

             for ( int i = 0 ; i < listTaskPro.Count; i ++ )
            {
                 if (listTaskPro[i].task.ParentID == 0 )
                {
                    listTaskPro[i].left = this .canvas1.Width / 2 ;
                }
                 else
                {
                    var childCount = listTaskPro.Where(m => m.task.ParentID == listTaskPro[i].task.ParentID).Count();
                    var parentLeft = listTaskPro.Where(m => m.task.ID == listTaskPro[i].task.ParentID).FirstOrDefault().left;
                    var perLength = parentLeft * 1.5 / (childCount + 1 );
                    listTaskPro[i].left = listTaskPro[i].index * perLength;
                }
            }
             foreach (TaskPro t in listTaskPro)
            {
                AddBtn(t.task.Name, t.left, t.top);
                 if (t.task.ParentID != 0 )
                {
                    TaskPro tp = listTaskPro.Where(m => m.task.ID == t.task.ParentID).FirstOrDefault();
                    AddLine(tp.left + buttonWidth / 2 , tp.top + buttonHeight, t.left + buttonWidth / 2 , t.top);
                }
            }
        }
         double buttonHeight = 20 ;
         double buttonWidth = 50 ;
         void AddBtn( string content, double left, double top)
        {
            Button btn = new Button();
            btn.Content = content;
            btn.Width = buttonWidth;
            btn.Height = buttonHeight;
             this .canvas1.Children.Add(btn);
            Canvas.SetLeft(btn, left);
            Canvas.SetTop(btn, top);
        }

         void AddLine( double startLeft, double startTop, double endLeft, double endTop)
        {
            Path p = new Path();
            LineGeometry geometry = new LineGeometry();
            SolidColorBrush brush = new SolidColorBrush();

            brush.Color = Colors.Black;
            geometry.StartPoint = new Point(startLeft, startTop);
            geometry.EndPoint = new Point(endLeft, endTop);
            p.Data = geometry;
            p.Stroke = brush;
            p.StrokeThickness = 1 ;

            canvas1.Children.Add(p);
        }
    }
}

一起谈.NET技术，Silverlight中使用递归构造关系图

需求

实现方法思考

实现步骤

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