How do i check if i tem already exist in ToolStripMenuItem.DropDownItems?

Question

I have a ToolStripMenuItem MouseEnter event:

private void recentFilesToolStripMenuItem_MouseEnter(object sender, EventArgs e)
{
    for (int i = 0; i < lines.Length; i++)
    {
        ToolStripMenuItem s = new ToolStripMenuItem(lines[i]);
            if (!recentFilesToolStripMenuItem.DropDownItems.ContainsKey(lines[i]))
            recentFilesToolStripMenuItem.DropDownItems.Add(s);

    }            
}

Now I am using ContainsKey but before i tried only with Contains(s) In both cases it keep adding the items over and over again to the DropDownItems. Each time i move the mouse and Enter i see the items added again. In this case lines is array of string contain paths and names of text files.

For example in lines index 0 i see: d:\\mytext.txt

The problem is that it keep adding them over again when i enter with the mouse and i want them to be added only once.

First time i see when entering with the mouse:

d:\mytext.txt
e:\test.txt
c:\hello\hellowowrld.txt

Next time when I enter with the mouse I see it twice:

d:\mytext.txt
e:\test.txt
c:\hello\hellowowrld.txt
d:\mytext.txt
e:\test.txt
c:\hello\hellowowrld.txt

Then next time i see the same items 9 times and so on.

Answer 1

There are two ways to do this.

One, is that you create your ToolStripMenuItem like this:

new ToolStripMenuItem(lines[i], (Image)null, (EventHandler)null, lines[i]);

It's that fourth parameter that is the "key" for .ContainsKey(...) , not the first parameter.

Two, you can do it this way:

if (!recentFilesToolStripMenuItem.DropDownItems
        .Cast<ToolStripMenuItem>()
        .Any(x => x.Text == lines[i]))
{
    recentFilesToolStripMenuItem.DropDownItems.Add(s);
}

This second way searches the actual text.