自定義樹形視圖

Question

有沒有辦法自定義一個winform treeview來獲取類似的東西？

的目的是爲具有由父項一種顏色一個定義一個三角形，而不是+/-圖標來開發項目。

Answer 1

使用TreeViewDrawMode.OwnerDrawText所以縮進將由TreeView進行調整。除此之外，你應該實施完整的繪畫。

public sealed class AdvancedTreeView : TreeView 
{ 
    public AdvancedTreeView() 
    { 
     DrawMode = TreeViewDrawMode.OwnerDrawText; 
     ShowLines = false; 
     AlternateBackColor = BackColor; 
    } 

    public Color AlternateBackColor { get; set; } 

    protected override void OnDrawNode(DrawTreeNodeEventArgs e) 
    { 
     // background 
     Color backColor = (GetTopNodeIndex(e.Node) & 1) == 0 ? BackColor : AlternateBackColor; 
     using (Brush b = new SolidBrush(backColor)) 
     { 
      e.Graphics.FillRectangle(b, new Rectangle(0, e.Bounds.Top, ClientSize.Width, e.Bounds.Height)); 
     } 

     // icon 
     if (e.Node.Nodes.Count > 0) 
     { 
      Image icon = GetIcon(e.Node.IsExpanded); // TODO: true=down;false:right 
      e.Graphics.DrawImage(icon, e.Bounds.Left - icon.Width - 3, e.Bounds.Top); 
     } 

     // text (due to OwnerDrawText mode, indenting of e.Bounds will be correct) 
     TextRenderer.DrawText(e.Graphics, e.Node.Text, Font, e.Bounds, ForeColor); 

     // indicate selection (if not by backColor): 
     if ((e.State & TreeNodeStates.Selected) != 0) 
      ControlPaint.DrawFocusRectangle(e.Graphics, e.Bounds); 
    } 

    private int GetTopNodeIndex(TreeNode node) 
    { 
     while (node.Parent != null) 
      node = node.Parent; 

     return Nodes.IndexOf(node); 
    } 
} 

爲了得到與截圖類似的結果，只需設置顏色即可。

advancedTreeView1.BackColor = Color.DeepSkyBlue; 
advancedTreeView1.AlternateBackColor = Color.LightBlue; 

Answer 2

只需在TreeView的屬性中將DrawMode設置爲「OwnerDrawAll」即可。請記住，你必須自己繪製它，並且必須處理TreeView_DrawNode事件。下面是事件處理的例子：

private void TreeListView_DrawNode(object sender, DrawTreeNodeEventArgs e) 
    { 
     if (e.Bounds.Height == 0) 
      return; 

     e.Graphics.FillRectangle(new SolidBrush((e.Node.Parent?.Index ?? e.Node.Index) % 2 == 0 ? Color.Blue : Color.Aqua), e.Bounds); 

     if (e.Node.Nodes.Count > 0) 
     { 
      if (!e.Node.IsExpanded) 
       e.Graphics.FillPolygon(Brushes.Red, 
        new[] 
        { 
         new PointF(e.Bounds.X + e.Bounds.Height/10, e.Bounds.Y + e.Bounds.Height/10), 
         new PointF(e.Bounds.X + e.Bounds.Height/10, e.Bounds.Y + e.Bounds.Height * 0.9f), 
         new PointF(e.Bounds.X + e.Bounds.Height, e.Bounds.Y + e.Bounds.Height/2) 
        }); 
      else 
       e.Graphics.FillPolygon(Brushes.Red, 
        new[] 
        { 
         new PointF(e.Bounds.X + e.Bounds.Height/10, e.Bounds.Y + e.Bounds.Height/10), 
         new PointF(e.Bounds.X + e.Bounds.Height, e.Bounds.Y + e.Bounds.Height/10), 
         new PointF(e.Bounds.X + e.Bounds.Height/2, e.Bounds.Y + e.Bounds.Height) 
        }); 
     } 
     e.Graphics.DrawString(e.Node.Text, new Font(FontFamily.GenericMonospace, e.Bounds.Height * 0.7f), 
      new SolidBrush(Color.Black), 
      new Rectangle(e.Bounds.X + e.Bounds.Height, e.Bounds.Y, e.Bounds.Width, e.Bounds.Height)); 
    }