I am using .Net compact framework so I was unable to perform to copy the string of the selected item and put it into clipboard. But Now I have done it.
This is what I did:
private void mnuCopy_click(object sender, EventArgs e)
{
string ind1 = listView1.SelectedIndices[0].ToString();
int ind2 = Convert.ToInt16(ind1);
string item = listView1.Items[ind2].Text;
Clipboard.SetDataObject(item);
}