Update:
To me it only works if you change CharSet.Auto to CharSet.Ansi. Since I don't know if it "should" work with the Auto setting, I don't change the code below, but just add the comment up here.
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;
public String lpVerb;
public String lpFile;
public String lpParameters;
public String lpDirectory;
public int nShow;
public int hInstApp;
public int lpIDList;
public String lpClass;
public int hkeyClass;
public uint dwHotKey;
public int hIcon;
public int 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.
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);
}
Verbs for lpVerb:
"open" - see MSDN
"edit" - see MSDN
"openas" - Opens dialog when no program is associated to the extension
"explore" - see MSDN
"properties" - see MSDN
