TreeNode选择BackColor,而TreeView没有聚焦

Question

在TreeView没有焦点的情况下,有一种简单的方法可以让选定的TreeNode保留其SystemColors.Highlight BackColor吗？因为即使将HideSelection设置为false,也几乎无法看到所选的BackColor.

TreeView具有焦点时选择的TreeNode:

TreeView没有焦点时选择的TreeNode:

提前致谢.

编辑:我知道我可以将DrawMode设置为OwnerDrawAll然后添加自定义DrawNode事件.我之前尝试过这个问题,我遇到的问题是我不知道如何正确地绘制TreeNode的相应ImageKey.

Answer 1

如果保留SystemColors.Highlight背景颜色是你想要的,那么你不需要将TreeView's DrawMode属性设置为TreeViewDrawMode.OwnerDrawAll.设置它TreeViewDrawMode.OwnerDrawText应该足够了,因此你不必担心绘制TreeNode相应的ImageKey.

1. 设置TreeView.DrawMode为TreeViewDrawMode.OwnerDrawText:

   treeView.DrawMode = TreeViewDrawMode.OwnerDrawText;
   

2. 设置Treview.HideSelection为false,以便节点状态将保持为选中状态:

   treeView.HideSelection= false;
   

3. 添加DrawNode事件处理程序以使用SystemColors.Highlight颜色绘制背景:

   private void treeView_DrawNode(object sender, DrawTreeNodeEventArgs e)
   {
     if (e.Node == null) return;
   
     // if treeview's HideSelection property is "True", 
     // this will always returns "False" on unfocused treeview
     var selected = (e.State & TreeNodeStates.Selected) == TreeNodeStates.Selected;
     var unfocused = !e.Node.TreeView.Focused;
   
     // we need to do owner drawing only on a selected node
     // and when the treeview is unfocused, else let the OS do it for us
     if (selected && unfocused)
     {
       var font = e.Node.NodeFont ?? e.Node.TreeView.Font;
       e.Graphics.FillRectangle(SystemBrushes.Highlight, e.Bounds);
       TextRenderer.DrawText(e.Graphics, e.Node.Text, font, e.Bounds, SystemColors.HighlightText, TextFormatFlags.GlyphOverhangPadding);
     }
     else
     {
       e.DrawDefault = true;
     }
   }
   

Answer 2

解决方案,就像一个魅力:

public TreeNode previousSelectedNode = null;
private void treeView1_Validating(object sender, System.ComponentModel.CancelEventArgs e)
{
    treeView1.SelectedNode.BackColor = SystemColors.Highlight;
    treeView1.SelectedNode.ForeColor = Color.White;
    previousSelectedNode = treeView1.SelectedNode;
}

private void treeView1_AfterSelect(object sender, TreeViewEventArgs e)
{
    if(previousSelectedNode != null)
    {
        previousSelectedNode.BackColor = treeView1.BackColor;
        previousSelectedNode.ForeColor = treeView1.ForeColor;
    }
}

Answer 3

我使用这个解决方案，它的效果更好

private void treeView1_Enter(object sender, EventArgs e)
{
   if (treeView1.SelectedNode != null)
   {
       treeView1.SelectedNode.BackColor = Color.Empty;
       treeView1.SelectedNode.ForeColor = Color.Empty;
   }
}

private void treeView1_Leave(object sender, EventArgs e)
{
   if (treeView1.SelectedNode != null)
   {
       treeView1.SelectedNode.BackColor = SystemColors.Highlight;
       treeView1.SelectedNode.ForeColor = Color.White;
   }
}

编辑

基于此文档，

默认为 Color.Empty

所以，treeView1_Enter最好像这样设置颜色

treeView1.SelectedNode.BackColor = Color.Empty;
treeView1.SelectedNode.ForeColor = Color.Empty;

上一个答案

treeView1.SelectedNode.BackColor = treeView1.BackColor;
treeView1.SelectedNode.ForeColor = treeView1.ForeColor;