C# Signature:
[DllImport("shell32.dll", EntryPoint = "SHOpenWithDialog", CharSet = CharSet.Unicode)]
private static extern int SHOpenWithDialog(IntPtr hWndParent, ref tagOPENASINFO oOAI);
User-Defined Types:
// http://msdn.microsoft.com/en-us/library/windows/desktop/bb773363(v=vs.85).aspx
private struct tagOPENASINFO
{
[MarshalAs(UnmanagedType.LPWStr)]
public string cszFile;
[MarshalAs(UnmanagedType.LPWStr)]
public string cszClass;
[MarshalAs(UnmanagedType.I4)]
public tagOPEN_AS_INFO_FLAGS oaifInFlags;
}
[Flags]
private enum tagOPEN_AS_INFO_FLAGS
{
OAIF_ALLOW_REGISTRATION = 0x00000001, // Show "Always" checkbox
OAIF_REGISTER_EXT = 0x00000002, // Perform registration when user hits OK
OAIF_EXEC = 0x00000004, // Exec file after registering
OAIF_FORCE_REGISTRATION = 0x00000008, // Force the checkbox to be registration
OAIF_HIDE_REGISTRATION = 0x00000020, // Vista+: Hide the "always use this file" checkbox
OAIF_URL_PROTOCOL = 0x00000040, // Vista+: cszFile is actually a URI scheme; show handlers for that scheme
OAIF_FILE_IS_URI = 0x00000080 // Win8+: The location pointed to by the pcszFile parameter is given as a URI
}
Alternative Managed API:
Do you know one? Please contribute it!
Notes:
Requires Windows Vista or later; on earlier platforms, use rundll32 to run OpenAs
Tips & Tricks:
Please add some!
Sample Code:
public static void DoOpenFileWith(string sFilename)
{
if (Environment.OSVersion.Version.Major > 5)
{
IntPtr hwndParent = IntPtr.Zero;
if (null != MyAppForm) hwndParent = MyAppForm.Handle;
tagOPENASINFO oOAI = new tagOPENASINFO();
oOAI.cszFile = sFilename;
oOAI.cszClass = String.Empty;
oOAI.oaifInFlags = tagOPEN_AS_INFO_FLAGS.OAIF_ALLOW_REGISTRATION | tagOPEN_AS_INFO_FLAGS.OAIF_EXEC;
SHOpenWithDialog(hwndParent, ref oOAI);
}
else
{
using (Process.Start("rundll32", "shell32.dll,OpenAs_RunDLL " + sFilename)) { }
}
}
