正确渲染重写的TreeView

Question

我在使用标准的Windows Forms TreeView时遇到了麻烦; 特别是当树视图没有焦点时,默认控件用于渲染所选节点的颜色.这是浅灰色,在某些屏幕上几乎看不见.随后,我已经将TreeView子类化并覆盖了TreeView OnDrawNode事件,以便按照我的意愿为我的节点着色.这很好用,但现在'HotTracking'(当鼠标在给定的树节点上时激活突出显示)被我的自定义OnDrawNode事件覆盖.我不太熟悉这些Graphics类,并想知道如何修改我当前的子类以包含热跟踪？我知道我可以使用,e.Graphics.DrawLine(Pen pen, Point p1, Point p2);但这会变得混乱,有更简单的方法吗？

这是现有的代码:

class CustomTreeView : TreeView 
{
    public CustomTreeView() 
    {
        this.DrawMode = TreeViewDrawMode.OwnerDrawText;
    }

    // Override the drawMode of TreeView.
    protected override void OnDrawNode(DrawTreeNodeEventArgs e) 
    {
        TreeNodeStates treeState = e.State;
        Font treeFont = e.Node.NodeFont ?? e.Node.TreeView.Font;

        // Colors.
        Color foreColor = e.Node.ForeColor;
        string strDeselectedColor = @"#6B6E77", strSelectedColor = @"#94C7FC"; //@"#1ABEE8"; //@"#2FC0EE"; //@"#3A8FEA";
        Color selectedColor = System.Drawing.ColorTranslator.FromHtml(strSelectedColor);
        Color deselectedColor = System.Drawing.ColorTranslator.FromHtml(strDeselectedColor);

        // New brush.
        SolidBrush selectedTreeBrush = new SolidBrush(selectedColor);
        SolidBrush deselectedTreeBrush = new SolidBrush(deselectedColor);

        // Set default font color.
        if (foreColor == Color.Empty)
            foreColor = e.Node.TreeView.ForeColor;

        // Draw bounding box and fill.
        if (e.Node == e.Node.TreeView.SelectedNode) 
        {
            // Use appropriate brush depending on if the tree has focus.
            if (this.Focused)
            {
                foreColor = SystemColors.HighlightText;
                e.Graphics.FillRectangle(selectedTreeBrush /*SystemBrushes.Highlight*/, e.Bounds);
                ControlPaint.DrawFocusRectangle(e.Graphics, e.Bounds, foreColor, SystemColors.Highlight);
                TextRenderer.DrawText(e.Graphics, e.Node.Text, treeFont, e.Bounds, foreColor, TextFormatFlags.GlyphOverhangPadding);
            }
            else
            {
                foreColor = SystemColors.HighlightText;
                e.Graphics.FillRectangle(deselectedTreeBrush /*SystemBrushes.Highlight*/, e.Bounds);
                ControlPaint.DrawFocusRectangle(e.Graphics, e.Bounds, foreColor, SystemColors.Highlight);
                TextRenderer.DrawText(e.Graphics, e.Node.Text, treeFont, e.Bounds, foreColor, TextFormatFlags.GlyphOverhangPadding);
            }
        }
        else 
        {
            // This is firing but is being over written, perhaps by the above?
            if ((e.State & TreeNodeStates.Hot) == TreeNodeStates.Hot)
            {
                e.DrawDefault = true;
                e.Graphics.FillRectangle(SystemBrushes.Window, e.Bounds);
                TextRenderer.DrawText(e.Graphics, e.Node.Text, treeFont, e.Bounds, System.Drawing.Color.Blue, TextFormatFlags.GlyphOverhangPadding);
            }
            else
            {
                e.Graphics.FillRectangle(SystemBrushes.Window, e.Bounds);
                TextRenderer.DrawText(e.Graphics, e.Node.Text, treeFont, e.Bounds, foreColor, TextFormatFlags.GlyphOverhangPadding);
           }   
        }
    }

像往常一样,非常感谢您的时间.

Answer 1

您需要注意代码中的e.State.DrawTreeNodeEventArgs.State属性告诉您节​​点的运行情况,相应地选择颜色.还要检查TreeNode.DrawNode文档中显示的MSDN库示例以获取指导.