WPF：从WPF Diagram Designer Part 4学习分组、对齐、排序、序列化和常用功能

　　在前面三篇文章中我们介绍了如何给图形设计器增加移动、选择、改变大小及面板、缩略图、框线选择和工具箱和连接等功能，本篇是这个图形设计器系列的最后一篇，将和大家一起来学习一下如何给图形设计器增加分组、对齐、排序、序列化等功能。

WPF Diagram Designer - Part 4

分组：Group, Ungroup

由于WPF不允许一个对象作为多个其他元素的子对象存在，而当移动父对象时，模板也会Unload导致一些问题，所以在这个系列中对分组的实现方式是：当分组一组元素时，内部生成一个Group，这个Group内部其实也是一个DesignerItem对象，只是IsGroup=true而已，在分组时，内部的对象的ParentID都置为这个Group对象的Id

 public interface IGroupable 
 { 
     Guid ID { get; } 
     Guid ParentID { get; set; } 
     bool IsGroup { get; set; } 
 }

执行分组时的代码如下：

        private void Group_Executed(object sender, ExecutedRoutedEventArgs e)
        {
            var items = from item in this.SelectionService.CurrentSelection.OfType<DesignerItem>()
                        where item.ParentID == Guid.Empty
                        select item;

            Rect rect = GetBoundingRectangle(items);

            DesignerItem groupItem = new DesignerItem();
            groupItem.IsGroup = true;
            groupItem.Width = rect.Width;
            groupItem.Height = rect.Height;
            Canvas.SetLeft(groupItem, rect.Left);
            Canvas.SetTop(groupItem, rect.Top);
            Canvas groupCanvas = new Canvas();
            groupItem.Content = groupCanvas;
            Canvas.SetZIndex(groupItem, this.Children.Count);
            this.Children.Add(groupItem);

            foreach (DesignerItem item in items)
                item.ParentID = groupItem.ID;

            this.SelectionService.SelectItem(groupItem);
        }

当我们选择一个分组子对象时，设计器会选择这个分组以及分组的所有子对象

        internal void SelectItem(ISelectable item)
        {
            this.ClearSelection();
            this.AddToSelection(item);
        }

        internal void AddToSelection(ISelectable item)
        {
            if (item is IGroupable)
            {
                List<IGroupable> groupItems = GetGroupMembers(item as IGroupable);

                foreach (ISelectable groupItem in groupItems)
                {
                    groupItem.IsSelected = true;
                    CurrentSelection.Add(groupItem);
                }
            }
            else
            {
                item.IsSelected = true;
                CurrentSelection.Add(item);
            }
        }

对齐：Align (Left, Right, Top, Bottom, Centered horizontal, Centered vertical)、Distribute (horizontal, vertical)

        private void AlignLeft_Executed(object sender, ExecutedRoutedEventArgs e)
        {
            var selectedItems = from item in SelectionService.CurrentSelection.OfType<DesignerItem>()
                                where item.ParentID == Guid.Empty
                                select item;

            if (selectedItems.Count() > 1)
            {
                double left = Canvas.GetLeft(selectedItems.First());

                foreach (DesignerItem item in selectedItems)
                {
                    double delta = left - Canvas.GetLeft(item);
                    foreach (DesignerItem di in SelectionService.GetGroupMembers(item))
                    {
                        Canvas.SetLeft(di, Canvas.GetLeft(di) + delta);
                    }
                }
            }
        }

        private void AlignHorizontalCenters_Executed(object sender, ExecutedRoutedEventArgs e)
        {
            var selectedItems = from item in SelectionService.CurrentSelection.OfType<DesignerItem>()
                                where item.ParentID == Guid.Empty
                                select item;

            if (selectedItems.Count() > 1)
            {
                double center = Canvas.GetLeft(selectedItems.First()) + selectedItems.First().Width / 2;

                foreach (DesignerItem item in selectedItems)
                {
                    double delta = center - (Canvas.GetLeft(item) + item.Width / 2);
                    foreach (DesignerItem di in SelectionService.GetGroupMembers(item))
                    {
                        Canvas.SetLeft(di, Canvas.GetLeft(di) + delta);
                    }
                }
            }
        }

排序：Order (Bring forward, Bring to top, Send backward, Send to back)

        private void BringForward_Executed(object sender, ExecutedRoutedEventArgs e)
        {
            List<UIElement> ordered = (from item in SelectionService.CurrentSelection
                                       orderby Canvas.GetZIndex(item as UIElement) descending
                                       select item as UIElement).ToList();

            int count = this.Children.Count;

            for (int i = 0; i < ordered.Count; i++)
            {
                int currentIndex = Canvas.GetZIndex(ordered[i]);
                int newIndex = Math.Min(count - 1 - i, currentIndex + 1);
                if (currentIndex != newIndex)
                {
                    Canvas.SetZIndex(ordered[i], newIndex);
                    IEnumerable<UIElement> it = this.Children.OfType<UIElement>().Where(item => Canvas.GetZIndex(item) == newIndex);

                    foreach (UIElement elm in it)
                    {
                        if (elm != ordered[i])
                        {
                            Canvas.SetZIndex(elm, currentIndex);
                            break;
                        }
                    }
                }
            }
        }

序列化：Open, Save

使用XML保存，代码如下：

XElement serializedItems = new XElement("DesignerItems",
                          from item in designerItems
                          let contentXaml = XamlWriter.Save(((DesignerItem)item).Content)
                          select new XElement("DesignerItem",
                                      new XElement("Left", Canvas.GetLeft(item)),
                                      new XElement("Top", Canvas.GetTop(item)),
                                      new XElement("Width", item.Width),
                                      new XElement("Height", item.Height),
                                      new XElement("ID", item.ID),
                                      new XElement("zIndex", Canvas.GetZIndex(item)),
                                      new XElement("IsGroup", item.IsGroup),
                                      new XElement("ParentID", item.ParentID),
                                      new XElement("Content", contentXaml)
                                      )
                           );

读取的时候需要建立Connection

       private void Open_Executed(object sender, ExecutedRoutedEventArgs e)
        {
　　　　　　　...　
            foreach (XElement connectionXML in connectionsXML)
            {
                Guid sourceID = new Guid(connectionXML.Element("SourceID").Value);
                Guid sinkID = new Guid(connectionXML.Element("SinkID").Value);

                String sourceConnectorName = connectionXML.Element("SourceConnectorName").Value;
                String sinkConnectorName = connectionXML.Element("SinkConnectorName").Value;

                Connector sourceConnector = GetConnector(sourceID, sourceConnectorName);
                Connector sinkConnector = GetConnector(sinkID, sinkConnectorName);

                Connection connection = new Connection(sourceConnector, sinkConnector);
                Canvas.SetZIndex(connection, Int32.Parse(connectionXML.Element("zIndex").Value));
                this.Children.Add(connection);
            }
        }

常用功能：Cut, Copy, Paste, Delete，Print

        private void Cut_Executed(object sender, ExecutedRoutedEventArgs e)
        {
            CopyCurrentSelection();
            DeleteCurrentSelection();
        }

        private void Print_Executed(object sender, ExecutedRoutedEventArgs e)
        {
            SelectionService.ClearSelection();

            PrintDialog printDialog = new PrintDialog();

            if (true == printDialog.ShowDialog())
            {
                printDialog.PrintVisual(this, "WPF Diagram");
            }
        }

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