How to: Use Interop Assemblies to Import Settings
A VSPackage may import settings from the Visual Studio integrated development environment (IDE). The IDE uses a VSPackage's implementation of the IVsUserSettings interface to determine how the VSPackage's configuration is to be retrieved.
Note
The Managed Package Framework (MPF) provides a set of managed classes to facilitate the creation of Visual Studio extensions. To perform this task using the MPF, see How to: Import Settings By Using the Managed Package Framework.
To implement settings import on a VSPackage
Implement basic support for the Visual Studio settings mechanism.
Register the VSPackage as supporting the settings mechanism by defining one or more Custom Settings Points.
For more information, see Persisting Settings.
Declare that the VSPackage implements the IVsUserSettings interface, for instance:
public class MyPackage : IVsPackage, IVsUserSettings, IVsUserSettingsQueryEnsure that the VSPackage's implementation of the QueryInterface method supplies a IVsUserSettings interface when called with IID_IVsUserSettings. For example:
STDMETHODIMP MyPackage::QueryInterface(THIS_ REFIID riid, LPVOID FAR* ppvObj) { if (ppvObj == NULL) return E_POINTER; *ppvObj = NULL; if (riid == IID_IUnknown) *ppvObj = (LPVOID)(IUnknown *)(IClassFactory*)this; else if (riid == IID_IClassFactory) *ppvObj = (LPVOID)(IClassFactory *)this; else if (riid == IID_IVsPackage) *ppvObj = (LPVOID)(IVsPackage *)this; else if (riid == IID_IVsPersistSolutionOpts) *ppvObj = (LPVOID)(IVsPersistSolutionOpts *)this; else if (riid == IID_IVsPersistSolutionProps) *ppvObj = (LPVOID)(IVsPersistSolutionProps *)this; else if (riid == IID_IVsComponentSelectorProvider) *ppvObj = (LPVOID)(IVsComponentSelectorProvider *)this; else if (riid == IID_IVsUserSettings) *ppvObj = (LPVOID)(IVsUserSettings *)this; else if (riid == IID_IVsUserSettingsQuery) *ppvObj = (LPVOID)(IVsUserSettingsQuery *)this; if (*ppvObj) { AddRef(); return NOERROR; } return E_NOINTERFACE; }
Retrieve settings information.
To support retrieving settings information, a VSPackage must implement the ImportSettings method.
To read data, a VSPackage's implementation of the IVsUserSettings interface must use the first two arguments passed in by the IDE: the GUID of that Custom Settings Point's category, and an IVsSettingsReader interface.
A VSPackage's implementation of the ImportSettings method must check the category GUID passed in and choose the correct mechanism for the retrieving state.
In the example below, the ImportSettings method calls a different implementation for retrieving the command bar state as opposed to retrieving the key-binding state.
A VSPackage must use the supplied IVsSettingsReader interface to retrieve data to the settings file.
Note
If the settings information changes as a function of a Visual Studio version, a VSPackage's implementation of the ImportSettings method must use the ReadFileVersion method prior to reading data to check the IDE version.
The interface provides methods for reading different data types from the settings file.
interface IVsSettingsReader : IUnknown
{
HRESULT ReadSettingString(WCHAR *pszSettingName, BSTR *pbstrSettingValue);
HRESULT ReadSettingLong(WCHAR *pszSettingName, long *plSettingValue);
HRESULT ReadSettingBoolean(WCHAR *pszSettingName, BOOL *pfSettingValue);
HRESULT ReadSettingAttribute(LPCOLESTR pszSettingName,LPCOLESTR pszAttributeName, BSTR *pbstrSettingValue); //Internal use only
HRESULT ReadSettingBytes(WCHAR *pszSettingName, BYTE *pSettingValue, long *plDataLength, long lDataMax);
HRESULT ReadVersion(int *pnMajor, int *pnMinor, int *pnBuild);
HRESULT ReportError(WCHAR *pszError);
};
The settings file supports random data access, so the order of read and write settings operations is not important.
This is illustrated in the exporting and importing command bar state (ExportSettings_CommandBar and ImportSettings_CommandBar) of the implementation in the example below.
Validate retrieved data.
The settings information is contained in XML files, which can be edited manually.
.gif "Security note") Security Note |
|---|
The settings information may become corrupt on disk, may contain version-specific settings, and could be used as a vehicle for malicious attack. The validity of each data item returned by the IVsSettingsReader method should be validated. |
To verify support of the version of Visual Studio used to produce the retrieved settings, call the ReadFileVersion method to retrieve the version.
To cause the IDE to notify a user that an imported data element does not validate, a VSPackage calls the ReportError method.
Apply settings information.
The implementation of the ImportSettings method must respect the value of the third argument that the IDE passed to it. The supported values are members of the __UserSettingsFlags enumeration. For more information, see __UserSettingsFlags.
In the example below, the implementation for importing command bar settings (ImportSettings_Commandbar) uses the value of this argument to determine whether to apply settings to overwrite existing values or to additively update them.
You must implement a write-through cache methodology when applying imported settings.
State information in the registry or the file system must be updated at the same time as settings are applied to the IDE. This guarantees configuration coherence and supports multi-instance IDE scenarios.
Alert IDE how to handle settings import.
Use the returned pfRestartRequired argument of the ImportSettings method to advise the IDE if a restart is required to apply the imported settings.
If the VSPackage's implementation of the ImportSettings method returns true, the user is prompted to restart the IDE.
Example
This example demonstrates how to import and export settings data.
static const WCHAR c_szFirstSettingName[] = L"FirstSettingName";
static const WCHAR c_szRandomTrashBytes[] = L"RandomTrashBytes";
static const WCHAR c_szRandomTrashLength[] = L"RandomTrashLength";
static const WCHAR c_szBreakPointWindow[] = L"Breakpoints Window";
// --------------------------------------------------------------------------
// IVsUserSettings methods used for configuration export and import
// Delegate to the right shell object based on the category GUID
// --------------------------------------------------------------------------
static const WCHAR c_szFirstSettingName[] = L"FirstSettingName";
static const WCHAR c_szRandomTrashBytes[] = L"RandomTrashBytes";
static const WCHAR c_szRandomTrashLength[] = L"RandomTrashLength";
static const WCHAR c_szBreakPointWindow[] = L"Breakpoints Window";
// Export Settings.
STDMETHOD(NeedExport)(WCHAR* pszCategoryGUID, BOOL *pfNeedExport)
{
if (!pfNeedExport)
return E_INVALIDARG;
CLSID clsidCategory;
HRESULT hr= S_OK;
hr = CLSIDFromString(pszCategoryGUID, &clsidCategory);
IfFailGo(hr);
if (GUID_Profiles_CommandBars == clsidCategory) {
*pfNeedExport = TRUE; //Always export Command Bar Configuration
}else if (GUID_Profiles_KeyBindings == clsidCategory) {
*pfNeedExport = FALSE; //By Default don't export key bindings
if (m_fMake_Permanent)
*pfNeedExport = TRUE; //Export if user wants current configuration saved.
}else{
hr = E_UNEXPECTED;
}
Error:
return hr;
}
STDMETHOD(ExportSettings)(WCHAR *pszCategoryGUID, IVsSettingsWriter *pSettings)
{
CLSID clsidCategory;
HRESULT hr;
hr = CLSIDFromString(pszCategoryGUID, &clsidCategory);
IfFailGo(hr);
// Delegate to the right internal implementation based on the requested category.
if (GUID_Profiles_CommandBars == clsidCategory) {
hr = ExportSettings_CommandBars(pSettings);
}else if (GUID_Profiles_KeyBindings == clsidCategory) {
hr = ExportSettings_KeyBindings(pSettings);
}else{
hr = E_UNEXPECTED;
}
Error:
return hr;
};
HRESULT ExportSettings_CommandBars(IVsSettingsWriter *pSettings)
{
if (!pSettings)
return E_INVALIDARG;
hr = pSettings->WriteSettingString(c_szFirstSettingName, L"Value1");
IfFailGo(hr);
int cRandomTrash = 12345;
BYTE *pRandomTrash = (BYTE *)VSAlloc(cRandomTrash);
if (pRandomTrash){
hr = pSettings->WriteSettingBytes(c_szRandomTrashBytes, pRandomTrash, cRandomTrash);
IfFailGo(hr);
hr = pSettings->WriteSettingLong(c_szRandomTrashLength, cRandomTrash);
IfFailGo(hr);
}
Error:
return hr;
};
HRESULT ExportSettings_KeyBindings(IVsSettingsWriter *pSettings)
{
if (!pSettings)
return E_INVALIDARG;
hr = pSettings->WriteSettingString(c_szBreakPointWindow, L"Ctrl + Alt + B");
IfFailGo(hr);
Error:
return hr;
};
STDMETHOD(ImportSettings)(WCHAR *pszCategoryGUID, IVsSettingsReader *pSettings, UserSettingsFlags flags, BOOL *pfRestartRequired)
{
CLSID clsidCategory;
HRESULT hr;
hr = CLSIDFromString(pszCategoryGUID, &clsidCategory);
IfFailGo(hr);
// Delegate to the right internal implementation based on the requested category.
if (GUID_Profiles_CommandBars == clsidCategory)
{
hr = ImportSettings_CommandBars(, pSettings, flags, pfRestartRequired);
}
else if (GUID_Profiles_KeyBindings == clsidCategory)
{
hr = ImportSettings_KeyBindings( pSettings, flags, pfRestartRequired);
}
else
{
hr = E_UNEXPECTED;
}
Error:
return hr;
};
// Import Settings.
HRESULT ImportSettings_CommandBars(IVsSettingsReader *pSettings, UserSettingsFlags flags, BOOL *pfRestartRequired)
{
if (!pSettings)
return E_INVALIDARG;
if (pfRestartRequired)
{
*pfRestartRequired = FALSE; //Nobody should require a restart!!
}
CComBSTR bstrFirstSettingName;
long lTrashLength = 0;
BYTE *pTrashBytes = NULL;
// Determines whether to import as an additive operation, or a reset all settings operation.
BOOL fResetCompletely = FALSE;
if (flags & USF_ResetOnImport)
fResetCompletely = TRUE;
hr = pSettings->ReadSettingString(c_szFirstSettingName, &bstrFirstSettingName);
IfFailGo(hr);
hr = pSettings->ReadSettingLong(c_szRandomTrashLength, &lTrashLength);
IfFailGo(hr);
if (lTrashLength > 0)
{
pTrashBytes = (BYTE*)VSAlloc(lTrashLength);
IfNullMemGo(pTrashBytes);
long lDataRead = 0;
hr = pSettings->ReadSettingBytes(c_szRandomTrashLength, pTrashBytes, &lDataRead, lTrashLength);
IfFailGo(hr);
if (lDataRead != lTrashLength)
{
hr = E_UNEXPECTED;
goto Error;
}
}
// Note: before returning these settings should immediately be applied to your personal
// settings store, whether in the registry or the file system.
// This write-thru cache methodology is essential to work in multi-instance IDE scenarios.
hr = UpdateState_CommandBar(bstrFirstSettingName,lTrashLength,pTrashBytes,lDataRead);
Error:
return hr;
};
HRESULT ImportSettings_KeyBindings(IVsSettingsReader *pSettings, UserSettingsFlags flags, BOOL *pfRestartRequired)
{
if (!pSettings)
return E_INVALIDARG;
if (pfRestartRequired)
{
*pfRestartRequired = FALSE; //Nobody should require a restart!!
}
CComBSTR bstrBreakPointWindow;
// Determines whether to import as an additive operation or a reset all settings operation.
BOOL fResetCompletely = FALSE;
if (flags & USF_ResetOnImport)
fResetCompletely = TRUE;
hr = pSettings->ReadSettingString(c_szBreakPointWindow, &bstrBreakPointWindow);
IfFailGo(hr);
// Note: before returning these settings should immediately be applied to your personal
// settings store, whether in the registry or the file system.
// This write-thru cache methodology is essential to work in multi-instance IDE scenarios.
hr = UpdateState_KeyBindings(bstrBreakPointWindow);
Error:
return hr;
}
See Also
Tasks
How to: Export Settings By Using Interop Assemblies