How to draw watermark on Listbox using C#

Question

Is it possible to draw a water mark text or image on ListBox, in the following listbox, it contains several files which has the same file extension(file type, in this case it's .abc), so I want to draw the file extension as water mark,

any suggestions or guidance would be much appreciated & Thanks for your time..:)

Answer 1

This example should do exactly what you are looking for:

public Form1()
{
  InitializeComponent();

  // Example Item
  listBox1.Items.Add("c:\\Folder1\\example1.abc");
  listBox1.Items.Add("c:\\Folder1\\example2.abc");
  listBox1.Items.Add("c:\\Folder1\\example3.abc");
  listBox1.Items.Add("c:\\Folder1\\example4.abc");
  listBox1.Items.Add("c:\\Folder1\\example5.abc");
  listBox1.Items.Add("c:\\Folder1\\example6.abc");

  // Without this listBox1.DrawItem won't fire
  listBox1.DrawMode = DrawMode.OwnerDrawVariable;

  // Subscribe event
  listBox1.DrawItem += listBox1_DrawItem;
}

private void listBox1_DrawItem(object sender, DrawItemEventArgs e)
{
  // Make sure listbox contains items
  if (listBox1.Items.Count == 0)
    return;

  // In this example ext will be ".abc"
  string ext = Path.GetExtension(listBox1.Items[0].ToString());

  // Draw items
  e.DrawBackground();
  e.DrawFocusRectangle();
  e.Graphics.DrawString(listBox1.Items[e.Index].ToString(), e.Font, SystemBrushes.WindowText, e.Bounds.Location);

  // Transparence
  // 255 = Full Visible
  //  0  = Invisible
  Color clr = Color.FromArgb(20, Color.Red);

  // Modify the position, font and Brush to your need
  e.Graphics.DrawString(ext, SystemFonts.DefaultFont, new SolidBrush(clr), new PointF(200F, 200F));
}