[DllImport("shlwapi.dll")]
static extern int SHAutoComplete(IntPtr
Handle, uint Flags);
enum AutoCompleteFlags : uint
{
Default = 0x00000000,
FileSystem = 0x00000001,
UrlHistory = 0x00000002,
UrlMenu = 0x00000004,
UseTab = 0x00000008,
FileSystemOnly = 0x00000010,
UrlAll = UrlHistory|UrlMenu,
FileSystemDirs = 0x00000020,
AutoSuggestForceOn = 0x10000000,
AutoSuggestForceOff = 0x20000000,
AutoAppendForceOn = 0x40000000,
AutoAppendForceOff = 0x80000000
}
SHAutoComplete(textBox1.Handle, (uint)AutoCompleteFlags.UrlHistory);