Walkthrough: Calling Code from VBA in a Visual Basic Project

This walkthrough demonstrates how to call a method in a document-level customization for Microsoft Office Word from Visual Basic for Applications (VBA) code in the document. The procedure involves three basic steps: add a method to the ThisDocument host item class, expose the method to VBA code, and then call the method from VBA code in the document.

Applies to: The information in this topic applies to document-level projects for the following applications: Excel 2007 and Excel 2010; Word 2007 and Word 2010. For more information, see Features Available by Office Application and Project Type.

Although this walkthrough uses Word specifically, the concepts demonstrated by the walkthrough also apply to document-level projects for Excel.

This walkthrough illustrates the following tasks:

  • Creating a document that contains VBA code.

  • Trusting the location of the document by using the Trust Center in Word.

  • Adding a method to the ThisDocument host item class.

  • Exposing the method to VBA code.

  • Calling the method from VBA code.


Your computer might show different names or locations for some of the Visual Studio user interface elements in the following instructions. The Visual Studio edition that you have and the settings that you use determine these elements. For more information, see Working with Settings.

link to video For a related video demonstration, see How Do I: Call VSTO Code from VBA?.

You need the following components to complete this walkthrough:

The first step is to create a macro-enabled document that contains a simple VBA macro. The document must contain a VBA project before you create a Visual Studio project that is based on that document. Otherwise, Visual Studio cannot modify the VBA project to enable VBA code to call into the customization assembly.

If you already have a document that contains VBA code that you want to use, you can skip this step.

To create a document that contains VBA code

  1. Start Word.

  2. Save the active document as a Word Macro-Enabled Document (*.docm) with the name DocumentWithVBA. Save it in a convenient location, such as the desktop.

  3. On the Ribbon, click the Developer tab.


    If the Developer tab is not visible, you must first show it. For more information, see How to: Show the Developer Tab on the Ribbon.

  4. In the Code group, click Visual Basic.

    The Visual Basic Editor opens.

  5. In the Project window, double-click ThisDocument.

    The code file for the ThisDocument object opens.

  6. Add the following VBA code to the code file. This code defines a simple function that does nothing. The only purpose of this function is to ensure that a VBA project exists in the document. This is required for later steps in this walkthrough.

    Sub EmptySub()
    End Sub
  7. Save the document and exit Word.

Now you can create a document-level project for Word that uses the macro-enabled document you created earlier.

To create a new project

  1. Start Visual Studio.

  2. On the File menu, point to New, and then click Project. If your IDE is set to use Visual Basic development settings, on the File menu, click New Project.

  3. In the templates pane, expand Visual Basic, and then expand Office.

  4. Select the 2010 or 2007 node.

  5. In the list of project templates, select the Word Document project.

  6. In the Name box, type CallingCodeFromVBA.

  7. Click OK.

    The Visual Studio Tools for Office Project Wizard opens.

  8. Select Copy an existing document, and, in the Full path of the existing document box, specify the location of the DocumentWithVBA document that you created earlier. If you are using your own macro-enabled document, specify the location of this document instead.

  9. Click Finish.

    Visual Studio opens the DocumentWithVBA document in the designer and adds the CallingCodeFromVBA project to Solution Explorer.

Before you can expose code in your solution to VBA code in the document, you must trust VBA in the document to run. There are several ways to do this. For this walkthrough, trust the location of the document in the Trust Center in Word.

To trust the location of the document

  1. Start Word.

  2. Click the File tab (for Word 2010) or the Microsoft Office Button (for Word 2007).

  3. Click the Word Options button.

  4. In the categories pane, click Trust Center.

  5. In the details pane, click Trust Center Settings.

  6. In the categories pane, click Trusted Locations.

  7. In the details pane, click Add new location.

  8. In the Microsoft Office Trusted Location dialog box, browse to the folder that contains the CallingCodeFromVBA project.

  9. Select Subfolders of this location are also trusted.

  10. In the Microsoft Office Trusted Location dialog box, click OK.

  11. In the Trust Center dialog box, click OK.

  12. In the Word Options dialog box, click OK.

  13. Exit Word.

Now that the VBA project is set up, add a method to the ThisDocument host item class that you can call from VBA code.

To add a method to the ThisDocument class

  1. In Solution Explorer, right-click ThisDocument.vb, and then click View Code.

    The ThisDocument.vb file opens in the Code Editor.

  2. Add the following method to the ThisDocument class. This method creates a table with two rows and two columns at the beginning of the document. The parameters specify the text that is displayed in the first row. Later in this walkthrough, you will call this method from VBA code in the document.

    Public Sub CreateTable(ByVal firstColumnHeader As String, _
        ByVal secondColumnHeader As String)
        Dim table1 As Word.Table = Me.Tables.Add(Me.Paragraphs(1).Range, 2, 2)
        With table1
            .Style = "Table Professional"
            .Cell(1, 1).Range.Text = firstColumnHeader
            .Cell(1, 2).Range.Text = secondColumnHeader
        End With
    End Sub
  3. Build the project.

To expose the CreateTable method to VBA code in the document, set the EnableVbaCallers property for the ThisDocument host item to True.

To expose the method to VBA code

  1. In Solution Explorer, double-click ThisDocument.vb.

    The DocumentWithVBA file opens in the designer.

  2. In the Properties window, select the EnableVbaCallers property, and change the value to True.

  3. Click OK in the message that is displayed.

  4. Build the project.

You can now call the CreateTable method from VBA code in the document.


In this walkthrough, you will add VBA code to the document while debugging the project. The VBA code you add to this document will be overwritten the next time that you build the project, because Visual Studio replaces the document in the build output folder with a copy of the document from the main project folder. If you want to save the VBA code, you can copy it into the document in the project folder. For more information, see Calling Code in Document-Level Customizations from VBA.

To call the method from VBA code

  1. Press F5 to run your project.

  2. On the Developer tab, in the Code group, click Visual Basic.

    The Visual Basic Editor opens.

  3. On the Insert menu, click Module.

  4. Add the following code to the new module.

    This code calls the CreateTable method in the customization assembly. The macro accesses this method by using the CallVSTOAssembly property of the ThisDocument object. This property was automatically generated when you set the EnableVbaCallers property earlier in this walkthrough.

    Sub CreateTable()
        Call ThisDocument.CallVSTOAssembly.CreateTable("Employee Name", "Start Date")
    End Sub
  5. Press F5.

  6. Verify that a new table was added to the document.

  7. Exit Word without saving your changes.

You can learn more about calling code in Office solutions from VBA in these topics:

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