Winform-TreeView

展开所有节点

this.treeView1.ExpandAll();

折叠所有节点

this.treeView1.CollapseAll();

选中节点

this.treeView1.HideSelection = false;--(即使在是去焦点时仍突出显示)

treeView1.SelectedNode = treenode;

判断选中节点是否是根节点

this.TreeView1.SelectedNode.Node.Parent==null;是根节点

this.TreeView1.SelectedNode.Level==0;根节点

判断选中节点是否是最里面的子节点

this.TreeView1.SelectedNode.Nodes.Count==0;如果是0则为最里面的子节点。

失去焦点仍然高亮显示

public FrmMain()
{
    InitializeComponent();
    treeView1.HideSelection = False;
    //自已绘制
    this.treeView1.DrawMode = TreeViewDrawMode.OwnerDrawText;
    this.treeView1.DrawNode += new DrawTreeNodeEventHandler(treeView1_DrawNode);
}

//在绘制节点事件中，按自已想的绘制
private void treeView1_DrawNode(object sender, DrawTreeNodeEventArgs e)
{
    e.DrawDefault = true; //我这里用默认颜色即可，只需要在TreeView失去焦点时选中节点仍然突显
    return;

    if ((e.State & TreeNodeStates.Selected) != 0)
    {
        //演示为绿底白字
        e.Graphics.FillRectangle(Brushes.DarkBlue, e.Node.Bounds);

        Font nodeFont = e.Node.NodeFont;
        if (nodeFont == null) nodeFont = ((TreeView)sender).Font;
        e.Graphics.DrawString(e.Node.Text, nodeFont, Brushes.White,Rectangle.Inflate(e.Bounds, 2, 0));
    }
    else
    {
        e.DrawDefault = true;
    }

    if ((e.State & TreeNodeStates.Focused) != 0)
    {
        using (Pen focusPen = new Pen(Color.Black))
        {
            focusPen.DashStyle = System.Drawing.Drawing2D.DashStyle.Dot;
            Rectangle focusBounds = e.Node.Bounds;
            focusBounds.Size = new Size(focusBounds.Width - 1,
            focusBounds.Height - 1);
            e.Graphics.DrawRectangle(focusPen, focusBounds);
        }
    }

}