Creating and Resolving shell links

• Download source code (5 Kb) (Requires VS .NET; Beta 2 won't do)

Introduction

ShortCut is a .NET class that allows you to create shortcuts to files as well as resolve existing shortcuts. The class was coded in Managed C++ and makes ample use of IJW. I have compiled the class as a Class Library under the namespace ShortCutLib. Thus you can now use it from your C# and VB .NET programs. Simply add a reference to the DLL. This is yet another example of how Managed C++ eases the transition between managed and unmanaged code so easily. It just works!

Sample Usage [C#]

using System;
using ShortCutLib;

namespace ShortCutTest
{
    class Class1
    {
        [STAThread]
        static void Main(string[] args)
        {
            ShortCut sc = new ShortCut();

            //Creating a shortcut
            sc.FilePath = "C:\\windows\\notepad.exe";
            sc.LnkPath = "c:\\abc.lnk";
            sc.LnkDesc = "This runs notepad";
            sc.WorkDir = "C:\\";
            sc.CreateLink();

            //Resolving a shortcut
            sc.LnkPath = "C:\\xyz.lnk";
            sc.ResolveLink();

            Console.WriteLine("File is {0}",sc.FilePath);
            Console.WriteLine("Description is {0}",sc.LnkDesc);
            Console.WriteLine("Woirking Dir is {0}",sc.WorkDir);
        }
    }
}

Source Listing (only the main header and cpp file)

For those of you who only have beta 2, you can use the following two source listings:

// ShortCut.h

#pragma once

using namespace System;
using namespace System::Runtime::InteropServices;

namespace ShortCutLib
{
    public __gc class ShortCut
    {
        private:
            String* m_filepath;
            String* m_workdir;
            String* m_lnkdesc;
            String* m_lnkpath;

            HRESULT _CreateLink(LPCWSTR FilePath, LPCWSTR LnkPath, 
                                LPCWSTR LnkDesc,LPCWSTR WorkDir);
            HRESULT _ResolveLink(LPCWSTR LnkFile, LPWSTR FilePath,
                                 LPWSTR LnkDesc,LPWSTR WorkDir);

        public:     
            __property String* get_FilePath()
            {
                return m_filepath;
            }
            __property void set_FilePath(String *str)
            {
                m_filepath = str;
            }
            __property String* get_WorkDir()
            {
                return m_workdir;
            }
            __property void set_WorkDir(String *str)
            {
                m_workdir = str;
            }
            __property String* get_LnkDesc()
            {
                return m_lnkdesc;
            }
            __property void set_LnkDesc(String *str)
            {
                m_lnkdesc = str;
            }
            __property String* get_LnkPath()
            {
                return m_lnkpath;
            }
            __property void set_LnkPath(String *str)
            {
                m_lnkpath = str;
            }
                
            bool CreateLink()
            {
                IntPtr strfilepath = Marshal::StringToCoTaskMemUni(FilePath);
                IntPtr strlnkpath = Marshal::StringToCoTaskMemUni(LnkPath);
                IntPtr strlnkdesc = Marshal::StringToCoTaskMemUni(LnkDesc);
                IntPtr strworkdir = Marshal::StringToCoTaskMemUni(WorkDir);
                
                HRESULT hres = _CreateLink((LPCWSTR)strfilepath.ToPointer(),
                                           (LPCWSTR)strlnkpath.ToPointer(),
                                           (LPCWSTR)strlnkdesc.ToPointer(),
                                           (LPCWSTR)strworkdir.ToPointer());

                Marshal::FreeCoTaskMem(strfilepath);
                Marshal::FreeCoTaskMem(strlnkpath);
                Marshal::FreeCoTaskMem(strlnkdesc);
                Marshal::FreeCoTaskMem(strworkdir);

                return (hres==S_OK);
            }

            bool ResolveLink()
            {
                wchar_t strfilepath[MAX_PATH];
                wchar_t strworkdir[MAX_PATH];
                wchar_t strlnkdesc[INFOTIPSIZE];

                IntPtr strlnkpath = Marshal::StringToCoTaskMemUni(LnkPath);         
                
                HRESULT hres = _ResolveLink((LPCWSTR)strlnkpath.ToPointer(),
                    strfilepath, strlnkdesc, strworkdir);

                FilePath = strfilepath;
                LnkDesc = strlnkdesc;
                WorkDir = strworkdir;
                    
                Marshal::FreeCoTaskMem(strlnkpath);         

                return (hres==S_OK);
            }
    };
}

// This is the main DLL file.

#include "stdafx.h"
#using <mscorlib.dll>
#include <Shlobj.h>
#include <crtdbg.h>
#include <atldef.h>
#include <atlconv.h>

#include "ShortCut.h"


HRESULT ShortCutLib::ShortCut::_CreateLink(LPCWSTR FilePath, 
    LPCWSTR LnkPath, LPCWSTR LnkDesc,LPCWSTR WorkDir) 
{ 
    USES_CONVERSION;
    CoInitialize(NULL);
    IShellLink* psl;             
    HRESULT  hres = CoCreateInstance(CLSID_ShellLink, NULL, 
            CLSCTX_INPROC_SERVER, IID_IShellLink, (LPVOID *) &psl); 
    if (SUCCEEDED(hres)) 
    { 
        IPersistFile* ppf; 
         
        psl->SetPath(W2A(FilePath)); 
        psl->SetWorkingDirectory(W2A(WorkDir));
        psl->SetDescription(W2A(LnkDesc)); 
            
        hres = psl->QueryInterface(IID_IPersistFile,(LPVOID*)&ppf); 
 
        if (SUCCEEDED(hres)) 
        {    
            hres = ppf->Save(LnkPath, TRUE); 
            ppf->Release(); 
        } 
        psl->Release(); 
    }
    CoUninitialize();
    return hres; 
} 

HRESULT ShortCutLib::ShortCut::_ResolveLink(LPCWSTR LnkFile, LPWSTR FilePath,
                                            LPWSTR LnkDesc,LPWSTR WorkDir) 
{ 
    CoInitialize(NULL);
    HRESULT hres; 
    IShellLink* psl; 
    WIN32_FIND_DATA wfd; 
    char strfilepath[MAX_PATH];     
    char strlnkdesc[INFOTIPSIZE];
    char strworkdir[MAX_PATH];

    USES_CONVERSION;
 
    hres = CoCreateInstance(CLSID_ShellLink, NULL, 
            CLSCTX_INPROC_SERVER, IID_IShellLink, (LPVOID *) &psl); 
    if (SUCCEEDED(hres)) 
    { 
        IPersistFile* ppf;         
        hres = psl->QueryInterface(IID_IPersistFile, (LPVOID *)&ppf); 
        if (SUCCEEDED(hres)) 
        { 
            hres = ppf->Load(LnkFile, STGM_READ); 
            if (SUCCEEDED(hres)) 
            {               
                hres = psl->Resolve(GetDesktopWindow(), 0); 
                if (SUCCEEDED(hres)) 
                { 
                    hres = psl->GetPath(strfilepath,MAX_PATH, &wfd, 
                                           SLGP_UNCPRIORITY );
                    
                    if (SUCCEEDED(hres)) 
                    {            
                        wcscpy(FilePath, A2W(strfilepath)); 
                        hres = psl->GetDescription(strlnkdesc,INFOTIPSIZE);
                    }

                    if (SUCCEEDED(hres)) 
                    {
                        wcscpy(LnkDesc,A2W(strlnkdesc));
                        hres = psl->GetWorkingDirectory(strworkdir,MAX_PATH);
                    }

                    if (SUCCEEDED(hres)) 
                    {
                        wcscpy(WorkDir,A2W(strworkdir));
                    }
                } 
            }         
            ppf->Release(); 
        }     
        psl->Release(); 
    } 
    CoUninitialize();
    return hres; 
} 

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