Well, take a look, this works, If you have problems please tell me:
using System.Drawing;
using System.Windows.Forms;
namespace WindowsFormsApplication1
{
public partial class Form1 : Form
{
public Form1() { InitializeComponent(); }
ToolTip tip = new ToolTip();
void richTextBox1_MouseMove(object sender, MouseEventArgs e)
{
if (!timer1.Enabled)
{
string link = GetWord(richTextBox1.Text, richTextBox1.GetCharIndexFromPosition(e.Location));
//Checks whether the current word i a URL, change the regex to whatever you want, I found it on www.regexlib.com.
//you could also check if current word is bold, underlined etc. but I didn't dig into it.
if (System.Text.RegularExpressions.Regex.IsMatch(link, @"^(http|https|ftp)\://[a-zA-Z0-9\-\.]+\.[a-zA-Z]{2,3}(:[a-zA-Z0-9]*)?/?([a-zA-Z0-9\-\._\?\,\'/\\\+&%\$#\=~])*$"))
{
tip.ToolTipTitle = link;
Point p = richTextBox1.Location;
tip.Show(link, this, p.X + e.X,
p.Y + e.Y + 32, //You can change it (the 35) to the tooltip's height - controls the tooltips position.
1000);
timer1.Enabled = true;
}
}
}
private void timer1_Tick(object sender, EventArgs e) //The timer is to control the tooltip, it shouldn't redraw on each mouse move.
{
timer1.Enabled = false;
}
public static string GetWord(string input, int position) //Extracts the whole word the mouse is currently focused on.
{
char s = input[position];
int sp1 = 0, sp2 = input.Length;
for (int i = position; i > 0; i--)
{
char ch = input[i];
if (ch == ' ' || ch == '\n')
{
sp1 = i;
break;
}
}
for (int i = position; i < input.Length; i++)
{
char ch = input[i];
if (ch == ' ' || ch == '\n')
{
sp2 = i;
break;
}
}
return input.Substring(sp1, sp2 - sp1).Replace("\n", "");
}
}
}