如何删除 treeview 节点 c# winform 上的默认蓝色背景

Question

I have a treeview but when I click on a node it displays a blue background. Do you have a solution to remove this blue background? I am using winform c# Thanks

Answer 1

To eliminate the blue background color of a node that is selected by mouse click, set the DrawMode property of the tree view to OwnerDrawText and handle the node label drawing as shown:

public partial class MainForm : Form
{
    public MainForm()
    {
        InitializeComponent();
        treeView.DrawMode = TreeViewDrawMode.OwnerDrawText;
        treeView.DrawNode += customDrawNode;
        treeView.AfterSelect += setTitleBarText;
    }

If the node is selected, custom draw the label. Non-selected nodes draw default.

    private void customDrawNode(object? sender, DrawTreeNodeEventArgs e)
    {
        if(sender is TreeView treeView)
        {
            if ((e.Node != null) && e.State.HasFlag(TreeNodeStates.Selected))
            {
                using (var brush = new SolidBrush(treeView.BackColor))
                {
                    e.Graphics.FillRectangle(brush, e.Bounds);
                }
                using (var brush = new SolidBrush(treeView.ForeColor))
                {
                    e.Graphics.DrawString(e.Node.Text, treeView.Font, brush, e.Bounds);
                }
                return;
            }
        }
        e.DrawDefault = true;
    }

Verify selected node by setting main form text.

    private void setTitleBarText(object? sender, TreeViewEventArgs e)
    {
        Text =
            treeView.SelectedNode == null ?
            "Main Form" :
            $"Main Form: {treeView.SelectedNode.Text}";
    }
}