Opens a Windows Explorer file/folder search for the specified query, with the option of a location. License: MIT

OpenWindowsExplorerSearch.cs

public void SearchWindowsExplorer(string query, string location = null)
{
  if (location != null && !Directory.Exists(location))
  {
    throw new ArgumentException("Directory does not exist.", "location");
  }
  string uri = "search:query=" + Uri.EscapeDataString(query) +
    (location == null ? string.Empty : "&crumb=location:" + Uri.EscapeDataString(location));
  Process.Start(uri);
}