Display content size for a folder in Explorer using shell extensions

• Download demo project - 20.2 Kb

Introduction

Let's take a look at the code

// remove all this stuff if you have the right shlobj.h file
// *** start stuff

typedef struct {
    GUID fmtid;
    DWORD pid;
} SHCOLUMNID, *LPSHCOLUMNID;
typedef const SHCOLUMNID* LPCSHCOLUMNID;


typedef struct {
    ULONG    dwFlags;
    ULONG    dwReserved;
    WCHAR    wszFolder[MAX_PATH];
} SHCOLUMNINIT, *LPSHCOLUMNINIT;

#define MAX_COLUMN_NAME_LEN 80
#define MAX_COLUMN_DESC_LEN 128

#pragma pack(1)
typedef struct {
    SHCOLUMNID  scid;
    VARTYPE     vt;
    DWORD       fmt;
    UINT        cChars;
    DWORD       csFlags; 
    WCHAR wszTitle[MAX_COLUMN_NAME_LEN];
    WCHAR wszDescription[MAX_COLUMN_DESC_LEN];
} SHCOLUMNINFO, *LPSHCOLUMNINFO;


#define SHCDF_UPDATEITEM        0x00000001      

typedef struct {
    ULONG   dwFlags;
    DWORD   dwFileAttributes;
    ULONG   dwReserved;
    WCHAR   *pwszExt;
    WCHAR   wszFile[MAX_PATH];
} SHCOLUMNDATA, *LPSHCOLUMNDATA;
typedef const SHCOLUMNDATA* LPCSHCOLUMNDATA;


DECLARE_INTERFACE_(IColumnProvider, IUnknown)
{
    // IUnknown methods
    STDMETHOD (QueryInterface)(THIS_ REFIID riid, void **ppv) PURE;
    STDMETHOD_(ULONG, AddRef)(THIS) PURE;
    STDMETHOD_(ULONG, Release)(THIS) PURE;

    // IColumnProvider methods
    STDMETHOD (Initialize)(THIS_ LPSHCOLUMNINIT psci) PURE;
    STDMETHOD (GetColumnInfo)(THIS_ DWORD dwIndex, LPSHCOLUMNINFO psci) PURE;
    STDMETHOD (GetItemData)(THIS_ LPCSHCOLUMNID pscid, LPCSHCOLUMNDATA pscd,
VARIANT *pvarData) PURE;
};

// *** end stuff

STDMETHODIMP CDirSizeColumn::GetColumnInfo ( DWORD dwIndex, 
    LPSHCOLUMNINFO psci )
{
    HRESULT hRes=S_FALSE;

    if (dwIndex==0)
    {
        psci->scid.fmtid = *_Module.pguidVer;   
        psci->scid.pid   = MY_COLUMN_ID;                               
        psci->vt         = VT_LPSTR;                                        
        psci->fmt        = LVCFMT_RIGHT;                                  
        psci->csFlags    = 0x22; // this is  SHCOLSTATE_TYPE_INT | 
                                 // SHCOLSTATE_SLOW
        psci->cChars     = 6;
        lstrcpyW ( psci->wszTitle, L"Content Size\0");
        lstrcpyW ( psci->wszDescription, 
             L"Size of all files and subfolders contained\0");
                            
        hRes=S_OK;
    }

    return hRes;
}

STDMETHODIMP CDirSizeColumn::GetItemData (
    LPCSHCOLUMNID   pscid,
    LPCSHCOLUMNDATA pscd,
    VARIANT*        pvarData )
{
    HRESULT hRes=S_FALSE;

    // is my module?
    if ( pscid->fmtid == *_Module.pguidVer )
    {
        // is a directory?
        if ( (pscd->dwFileAttributes & FILE_ATTRIBUTE_DIRECTORY)==
            FILE_ATTRIBUTE_DIRECTORY)
        {
            // is my column?
            if ( pscid->pid == MY_COLUMN_ID )
            {
                CString strFileName(pscd->wszFile);

                char szText[100];
                sprintf(szText,"%I64d KB",(__int64)(
                     GetDirSize(strFileName)/(__int64)1024));

                CComVariant vData(szText);

                vData.Detach ( pvarData );

                hRes=S_OK;
            }
        }
    }

    return hRes;
}

__int64 GetDirSize(CString strFileName)
{
    __int64 i64Size=0;

    TRY
    {
        CFileFind finder;
        BOOL bWorking = finder.FindFile(strFileName+"\\*.*");

        while (bWorking)
        {
            bWorking = finder.FindNextFile();

            // check for dots
            if (!finder.IsDots())
            {
                // check for recursion
                if (finder.IsDirectory())
                    i64Size=i64Size+GetDirSize(finder.GetFilePath());
                else
                    i64Size=i64Size+finder.GetLength64();
            }
        }
    }
    CATCH(CException, ex)
    {
        // catch any error here

        i64Size=0;
    }
    END_CATCH

    return i64Size;
}

Install/Uninstall

regsvr32 SHDireSizeColumn.dll

regsvr32 /u SHDireSizeColumn.dll

And then...

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