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IWMDMStorage2::GetStorage

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The GetStorage method retrieves a child storage by name directly from the current storage without having to enumerate through all the children.

Syntax

HRESULT GetStorage(LPWSTRpszStorageName,IWMDMStorage**ppStorage);

Parameters

pszStorageName

[in]  Pointer to a null-terminated string specifying the storage name. This is the name retrieved by IWMDMStorage::GetName.

ppStorage

[out]  Pointer to the retrieved storage object*,* or NULL if no storage was found. The caller must release this interface when done with it.

Return Values

The method returns an HRESULT. All the interface methods in Windows Media Device Manager can return any of the following classes of error codes:

  • Standard COM error codes
  • Windows error codes converted to HRESULT values
  • Windows Media Device Manager error codes

For an extenstive list of possible error codes, see Error Codes.

Possible values include, but are not limited to, those in the following table. If it fails with an error, it returns a standard error code.

Return code Description
S_OK The method succeeded.
S_FALSE No errors occurred, but the file was not found.

Remarks

IWMDMStorage2::GetStorage does not support wildcard characters. It is not recursive; that is, it will only find storages that are immediate children of the current storage. To find a storage more than one level deep, try IWMDMDevice3::FindStorage.

Example Code

The following C++ function searches for a storage recursively. It uses GetStorage to search the immediate children; if the requested storage is not found, it then loops through all the children and recursively searches folders.

HRESULT myFindStorageRecursively(LPCWSTR storageName, IWMDMStorage* pCurrentStorage, IWMDMStorage** ppFoundStorage)
{
    HRESULT hr = S_OK;

    // Start with a quick check of all storages inside the storage.
    // If we found it, stop now and return.
    CComQIPtr<IWMDMStorage2> pStorage2(pCurrentStorage);
    hr = pStorage2->GetStorage(storageName, ppFoundStorage);
    if (*ppFoundStorage != NULL)
        return hr;

    //
    // Otherwise, enumerate through and dive into all child folders.
    //

    // First get enumerator.
    CComPtr<IWMDMEnumStorage> pEnumStorage;
    hr = pCurrentStorage->EnumStorage(&pEnumStorage);
    if (hr != S_OK && pEnumStorage != NULL)
        return hr;

    // Now enumerate all folders until found the right item, or out of folders.
    CComPtr<IWMDMStorage> pThisStorage;
    DWORD numRetrieved = 0;
    DWORD attr = 0;
    while(pEnumStorage->Next(1, &pThisStorage, &numRetrieved) == S_OK)
    {
        pThisStorage->GetAttributes(&attr, NULL);
        if (attr & WMDM_FILE_ATTR_FOLDER)
        {
            hr = myFindStorageRecursively(storageName, pThisStorage, ppFoundStorage);
            if (*ppFoundStorage != NULL)
                return hr;
        }
        pThisStorage.Release();
    }

    return hr;
}

Requirements

Header: Defined in mswmdm.h.

Library: mssachlp.lib

See Also