由于需要,我不需要treeview控件的根节点上出现选择框(如下图)。自定义控件肯定是个办法,让我们先翻翻手册。
通过手册发现TreeView.DrawMode,用于指示TreeView 的节点或节点标签是否为自绘的还是系统绘制的,这是个枚举值。其中Normal为默认,代表完全有系统绘制;OwnerDrawText代表标签部分为手动绘制,其他元素由操作系统绘制,包括图标、复选框、加号和减号以及连接节点的线;OwnerDrawAll代表图标、复选框、加号和减号以及连接节点的线均为手工绘制。
因此我们可以设置此属性为 DrawMode=OwnerDrawAll 后,绑定TreeView.DrawNode事件就可以完成。下面是代码:
- void treeView1_DrawNode(object sender, DrawTreeNodeEventArgs e)
- {
- if (e.Node.Parent == null)
- {
- Color backColor, foreColor;
- if ((e.State & TreeNodeStates.Selected) == TreeNodeStates.Selected)
- {
- backColor = SystemColors.Highlight;
- foreColor = SystemColors.HighlightText;
- }
- else if ((e.State & TreeNodeStates.Hot) == TreeNodeStates.Hot)
- {
- backColor = SystemColors.HotTrack;
- foreColor = SystemColors.HighlightText;
- }
- else
- {
- backColor = e.Node.BackColor;
- foreColor = e.Node.ForeColor;
- }
- if (this.treeView1.ShowPlusMinus)
- {
- #region 画一个“加号”表示未展开的
- Pen pen = new Pen(Brushes.Black);
- Rectangle plusBound = new Rectangle(new Point(0, e.Bounds.Top), new Size(this.treeView1.Width, 18));
- e.Graphics.DrawRectangle(pen, plusBound.X + 7, plusBound.Y + 2, 10, 10);
- e.Graphics.DrawLine(pen, plusBound.X + 9, plusBound.Top + 7, plusBound.Left + 15, plusBound.Top + 7);
- if (!e.Node.IsExpanded)
- {
-
- e.Graphics.DrawLine(pen, plusBound.X + 12, plusBound.Top + 4, plusBound.Left + 12, plusBound.Top + 10);
- }
- #endregion
- }
- Rectangle newBounds = e.Node.Bounds;
- newBounds.X = 20;
-
- using (SolidBrush brush = new SolidBrush(backColor))
- {
- e.Graphics.FillRectangle(brush, newBounds);
- }
-
- TextRenderer.DrawText(e.Graphics, e.Node.Text, this.treeView1.Font, newBounds, foreColor, backColor);
-
- if ((e.State & TreeNodeStates.Focused) == TreeNodeStates.Focused)
- {
- ControlPaint.DrawFocusRectangle(e.Graphics, newBounds, foreColor, backColor);
- }
-
- e.DrawDefault = false;
- }
- else
- {
- e.DrawDefault = true;
- }
- }