Use the CallVSTOAssembly property to access public members that you added to the host item class. For example, the following VBA macro calls a method named MyVSTOMethod that is defined in the Sheet1 class in an Excel workbook project.

Sub MyMacro()
    Sheet1.CallVSTOAssembly.MyVSTOMethod()
End Sub

This property is a more convenient way to call into the customization assembly than using the GetManagedClass method directly. CallVSTOAssembly returns an object that represents the host item class that you exposed to VBA. The members and method parameters of the returned object appear in IntelliSense.

The CallVSTOAssembly property has a declaration that is similar to the following code. This code assumes that you have exposed the Sheet1 host item class in an Excel workbook project named ExcelWorkbook1 to VBA.

Property Get CallVSTOAssembly() As ExcelWorkbook1.Sheet1
    Set CallVSTOAssembly = GetManagedClass(Me)
End Property

To use the global GetManagedClass method, pass in the VBA object that corresponds to the host item class that contains your override of the GetAutomationObject method. Then, use the returned object to access the class that you exposed to VBA.

For example, the following VBA macro calls a method named MyVSTOMethod that is defined in the Sheet1 host item class in an Excel workbook project named ExcelWorkbook1.

Sub CallVSTOMethod
    Dim VSTOSheet1 As ExcelWorkbook1.Sheet1
    Set VSTOSheet1 = GetManagedClass(Sheet1)
    VSTOSheet1.MyVSTOMethod
End Sub

The GetManagedClass method has the following declaration.

GetManagedClass(pdispInteropObject Object) As Object

This method returns an object that represents the class that you exposed to VBA. The members and method parameters of the returned object appear in IntelliSense.

This location is convenient if you have complete control over both the VBA code in the document and the Visual Studio Tools for Office customization code. Because the document is on the development computer, you can easily modify the VBA code if you change the customization code. VBA code that you add to this copy of the document remains in the document when you build, debug, and publish your solution.

You cannot add the VBA code to the document while it is open in the designer. You must first close the document in the designer, and then open the document directly in Word or Excel.

Caution:
If you add VBA code that runs when the document is opened, in rare cases this code might corrupt the document or prevent it from opening in the designer.

In some cases, it might be suitable to add the VBA code to the document in the publish or installation folder. For example, you might choose this option if the VBA code is written and tested by a different developer on a computer that does not have Visual Studio Tools for Office installed.

If users install the solution directly from the publish folder, you must add the VBA code to the document every time you publish the solution. Visual Studio overwrites the document in the publish location when you publish the solution.

If users install the solution from an installation folder that is different from the publish folder, you can avoid adding the VBA code in the document every time you publish the solution. When a publish update is ready to be moved from the publish folder to the installation folder, copy all of the files to the installation folder except for the document.

If the end users are VBA developers who are calling into services that you provide in the Visual Studio Tools for Office customization, you can tell them how to call your code by using the CallVSTOAssembly property or the GetManagedClass method in their copies of the document. When you publish updates to the solution, VBA code in the document on the end user computer will not be overwritten, because the document is not modified by publish updates.

When you set the EnableVbaCallers property of a host item to True in a Visual Basic project, Visual Studio Tools for Office performs the following tasks:

1. It adds the ComClassAttribute and ComVisibleAttribute attributes to the host item class.

2. It overrides the GetAutomationObject method of the host item class.

3. It sets the ReferenceAssemblyFromVbaProject property of the host item to True.

When you set the EnableVbaCallers property back to False, Visual Studio Tools for Office performs the following tasks:

1. It removes the ComClassAttribute and ComVisibleAttribute attributes from the ThisDocument class.

2. It removes the GetAutomationObject method from the host item class.

   Note:
   Visual Studio Tools for Office does not automatically set the ReferenceAssemblyFromVbaProject property back to False. You can set this property to False manually by using the Properties window.

When the ReferenceAssemblyFromVbaProject property of any host item in a Visual Basic or Visual C# project is set to True, Visual Studio Tools for Office performs the following tasks:

1. It generates a type library for the customization assembly and embeds the type library in the assembly.

2. It adds a reference to the following type libraries in the VBA project in the document:

   • The type library for your customization assembly.

   • The Microsoft Visual Studio Tools for Office Execution Engine 9.0 Type Library. This type library is included in the Visual Studio Tools for Office runtime.

When the ReferenceAssemblyFromVbaProject property is set back to False, Visual Studio Tools for Office performs the following tasks:

1. It removes the type library references from the VBA project in the document.

2. It removes the embedded type library from the assembly.