IUIApplication::OnViewChanged method (uiribbon.h)

Article
02/22/2024

Called when the state of a View changes.

Syntax

HRESULT OnViewChanged(
  [in] UINT32      viewId,
  [in] UI_VIEWTYPE typeID,
  [in] IUnknown    *view,
  [in] UI_VIEWVERB verb,
  [in] INT32       uReasonCode
);

Parameters

[in] viewId

Type: UINT32

The ID for the View. Only a value of 0 is valid.

[in] typeID

Type: UI_VIEWTYPE

The UI_VIEWTYPE hosted by the application.

[in] view

Type: IUnknown*

A pointer to the View interface.

[in] verb

Type: UI_VIEWVERB

The UI_VIEWVERB (or action) performed by the View.

[in] uReasonCode

Type: INT32

Not defined.

Return value

Type: HRESULT

If this method succeeds, it returns S_OK. Otherwise, it returns an HRESULT error code.

Remarks

This callback notification is sent by the framework to the host application on each View state change.

Important This callback only occurs for the Ribbon View with a viewId of 0.

IUIApplication::OnViewChanged is useful for initializing Ribbon properties when the host application starts, modifying Ribbon properties based on user actions, such as resizing the application window, and querying Ribbon properties when the application closes.

Examples

The following example demonstrates a basic implementation of the IUIApplication::OnViewChanged method.

//
//  FUNCTION: OnViewChanged(UINT, UI_VIEWTYPE, IUnknown*, UI_VIEWVERB, INT)
//
//  PURPOSE: Called when the state of a View (Ribbon is a view) changes - like created/destroyed/resized.
//
//  PARAMETERS:    
//                viewId - The View identifier. 
//                typeID - The View type. 
//                pView - Pointer to the View interface. 
//                verb - The action performed by the View. 
//                uReasonCode - Not defined. 
//
//  COMMENTS:
//
//    For this sample, return the same command handler for all commands
//    specified in the .xml file.
//    
//
STDMETHODIMP CApplication::OnViewChanged(
    UINT viewId,
    UI_VIEWTYPE typeId,
    IUnknown* pView,
    UI_VIEWVERB verb,
    INT uReasonCode)
{
    HRESULT hr = E_NOTIMPL;
    
    // Checks to see if the view that was changed was a Ribbon view.
    if (UI_VIEWTYPE_RIBBON == typeId)
    {
        switch (verb)
        {            
            // The view was newly created.
            case UI_VIEWVERB_CREATE:
                _cwprintf(L"IUIApplication::OnViewChanged called with verb=CREATE\r\n");

                if (NULL == g_pRibbon)
                {
                    // Retrieve and store the IUIRibbon
                    hr = pView->QueryInterface(&g_pRibbon);
                }
                break;

            // The view was resized.  
            // In the case of the Ribbon view, the application should call 
            // GetHeight() to determine the height of the Ribbon.
            case UI_VIEWVERB_SIZE:
                _cwprintf(L"IUIApplication::OnViewChanged called with verb=SIZE\r\n");
                // Call to the framework to determine the height of the Ribbon.
                if (NULL != g_pRibbon)
                {
                    UINT uRibbonHeight;
                    hr = g_pRibbon->GetHeight(&uRibbonHeight);
                }
                if (!SUCCEEDED(hr))
                {
                    //_cwprintf(L"IUIRibbon::GetHeight() failed with hr=0x%X\r\n", hr);
                }
                break;
                
            // The view was destroyed.
            case UI_VIEWVERB_DESTROY:
                //_cwprintf(L"IUIApplication::OnViewChanged called with verb=DESTROY\r\n");
                g_pRibbon = NULL;
                hr = S_OK;
                break;
        }
    }
    return hr;
}

Requirements

Requirement	Value
Minimum supported client	Windows 7 [desktop apps only]
Minimum supported server	Windows Server 2008 R2 [desktop apps only]
Target Platform	Windows
Header	uiribbon.h
DLL	Mshtml.dll

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