HOWTO: How do I add commands to Excel's right-mouse menu?

How do I add commands to Excel's right-mouse menu?

Issue

I want my commands to appear when the user right-clicks in a spreadsheet. How do I do it?

Summary

1. Call the Excel API directly, using xlfAddCommand, to create the menu item.
2. Call the Excel API directly, using xlfDeleteCommand, to delete the menu item.

Example

The code below adds a command "My Context Menu Item" to the right-click menu when the add-in is opened, and removes it when the add-in is closed.

BOOL CContextMenuApp::OnXllOpenEx()
{
    // Add an item to the context menu, just before "Paste"
    static int xlfAddCommand = 153;
    CXlOper xloItem;
    xloItem.AllocArray(1, 2);
    xloItem[0] = "&My Context Menu Item";   // Text of menu item
    xloItem[1] = "MyAddinFunction";         // Name of macro function
    CXllApp::Excel(xlfAddCommand, 4, 
        &CXlOper(7, 0),
        &CXlOper(4, 0),
        &xloItem,
        &CXlOper("Paste")); // Menu item before which the new item will appear

    return TRUE;
}

void CContextMenuApp::OnXllClose()
{
    // Remove the item from the context menu
    static int xlfDeleteCommand = 159;
    CXllApp::Excel(xlfDeleteCommand, 3, 
        &CXlOper(7, 0),
        &CXlOper(4, 0),
        &CXlOper("&My Context Menu Item"));
}