C# Signature::
[DllImport("shell32.dll", CharSet = CharSet.Auto)]
static extern bool ShellExecuteEx(ref SHELLEXECUTEINFO lpExecInfo);
VB.NET Signature:
<DllImport("Shell32", CharSet:=CharSet.Auto, SetLastError:=True)> _
Public Function ShellExecuteEx(ByRef lpExecInfo As SHELLEXECUTEINFO) As Boolean
End Function
User-Defined Types:
(VB.NET)
Public Structure SHELLEXECUTEINFO
Public cbSize As Integer
Public fMask As Integer
Public hwnd As IntPtr
<MarshalAs(UnmanagedType.LPTStr)> Public lpVerb As String
<MarshalAs(UnmanagedType.LPTStr)> Public lpFile As String
<MarshalAs(UnmanagedType.LPTStr)> Public lpParameters As String
<MarshalAs(UnmanagedType.LPTStr)> Public lpDirectory As String
Dim nShow As Integer
Dim hInstApp As IntPtr
Dim lpIDList As IntPtr
<MarshalAs(UnmanagedType.LPTStr)> Public lpClass As String
Public hkeyClass As IntPtr
Public dwHotKey As Integer
Public hIcon As IntPtr
Public hProcess As IntPtr
End Structure
(C#)
[StructLayout(LayoutKind.Sequential, CharSet = CharSet.Auto)]
public struct SHELLEXECUTEINFO
{
public int cbSize;
public uint fMask;
public IntPtr hwnd;
[MarshalAs(UnmanagedType.LPTStr)]
public string lpVerb;
[MarshalAs(UnmanagedType.LPTStr)]
public string lpFile;
[MarshalAs(UnmanagedType.LPTStr)]
public string lpParameters;
[MarshalAs(UnmanagedType.LPTStr)]
public string lpDirectory;
public int nShow;
public IntPtr hInstApp;
public IntPtr lpIDList;
[MarshalAs(UnmanagedType.LPTStr)]
public string lpClass;
public IntPtr hkeyClass;
public uint dwHotKey;
public IntPtr hIcon;
public IntPtr hProcess;
}
Notes:
Check the SW constants at to see what value to pass in the nShow member. Typically you'll pass SW_SHOW.
lpVerb member can be used for a varity of actions like "properties", "find", "openas", "print"..etc depending on the file type you're dealing with.Actions available for a specific file type are stored in registry, setting lpVerb to null results in the default action of that file type to be executed.
The MSDN suggests that the various string members of SHELLEXECUTEINFO are all LPCTSTRs. Don't believe it: the truth is in the headers - in this case ShellAPI.h, which declares them all as LPCSTR i.e. they're always ANSI not Unicode.
Tips & Tricks:
(C#)
using System.Runtime.InteropServices;
(VB.NET)
Imports System.Runtime.InteropServices
Sample Code:
VB.NET
Demonstrates how to open an HTML file in the browser:
Dim info As SHELLEXECUTEINFO
info.cbSize = System.Runtime.InteropServices.Marshal.SizeOf(info)
info.lpVerb = "open"
info.lpFile = "somefile.html"
info.nShow = SW_SHOW
If Not ShellExecuteEx(info) Then
Dim ex As New System.ComponentModel.Win32Exception(System.Runtime.InteropServices.Marshal.GetLastWin32Error())
MessageBox.Show(ex.Message, "Error")
End If
Alternative Managed API:
The Process class uses ShellExecuteEx by default:
Dim p As New Process
p.StartInfo.FileName = "somefile.html"
p.StartInfo.ErrorDialog = True ' this opens the "Open With" dialog for unknown file types
p.Start()
C# Example of Property Dialog
private const int SW_SHOW = 5;
private const uint SEE_MASK_INVOKEIDLIST = 12;
[DllImport("shell32.dll")]
static extern bool ShellExecuteEx(ref SHELLEXECUTEINFO lpExecInfo);
public static void ShowFileProperties(string Filename) {
SHELLEXECUTEINFO info = new SHELLEXECUTEINFO();
info.cbSize = System.Runtime.InteropServices.Marshal.SizeOf(info);
info.lpVerb = "properties";
info.lpFile = Filename;
info.nShow = SW_SHOW;
info.fMask = SEE_MASK_INVOKEIDLIST;
ShellExecuteEx(ref info);
}
VB.NET Example of Property Dialog
Public Const SW_SHOW As Short = 5
Public Const SEE_MASK_INVOKEIDLIST As Short = 12
<DllImport("Shell32", CharSet:=CharSet.Auto, SetLastError:=True)> _
Public Shared Function ShellExecuteEx(ByRef lpExecInfo As SHELLEXECUTEINFO) As Boolean
End Function
Dim sei As New SHELLEXECUTEINFO
sei.cbSize = Marshal.SizeOf(sei)
sei.lpVerb = "properties"
sei.lpFile = "FilePath"
sei.nShow = SW_SHOW
sei.fMask = SEE_MASK_INVOKEIDLIST
If Not ShellExecuteEx(sei) Then
Dim ex As New System.ComponentModel.Win32Exception(System.Runtime.InteropServices.Marshal.GetLastWin32Error())
MessageBox.Show(ex.Message, Me.TITLE, MessageBoxButtons.OK, MessageBoxIcon.Exclamation)
End If
Verbs for lpVerb:
"open" - see MSDN
"openas" - Opens dialog when no program is associated to the extension
"opennew" - see MSDN
"edit" - see MSDN
"explore" - see MSDN
"properties" - see MSDN
"copy" - see MSDN
"cut" - see MSDN
"paste" - see MSDN
"pastelink" - pastes a shortcut
"delete" - see MSDN
"print" - see MSDN
"printto" - see MSDN
"find" - see MSDN
