Associate a form region with an Outlook message class

Applies to: Visual Studio Visual Studio for Mac

You can specify which Microsoft Office Outlook items display a form region by associating the form region with the message class of each item. For example, if you want to append a form region to the bottom of a mail item, you can associate the form region with the IPM.Note message class.

To associate a form region with a message class, specify the message class name in the New Outlook Form Region wizard or apply an attribute to the form region factory class.

Applies to: The information in this topic applies to VSTO Add-in projects for Outlook. For more information, see Features available by Office application and project type.

Understand Outlook message classes

An Outlook message class identifies a type of Outlook item. The following table lists these eight standard types of items and their message class names.

You can also specify the names of custom message classes. Custom message classes identify custom forms that you define in Outlook.

Associate a form region with an Outlook message class

There are two ways to associate a form region with a message class:

• Use the New Outlook Form Region wizard.

• Apply class attributes.

Use the New Outlook Form Region wizard

On the final page of the New Outlook Form Region wizard, you can select standard message classes and type the names of custom message classes that you want to associate with the form region.

The standard message classes are not available if the form region is designed to replace the whole form or the default page of a form. You can specify standard message class names only for forms that add a new page to a form or that are appended to the bottom of a form. For more information, see How to: Add a form region to an Outlook Add-in project.

To include one or more custom message classes, type their names in the Which custom message classes will display this form region? box.

The names that you type must comply with the following guidelines:

• Use the fully qualified message class name (for example: "IPM.Note.Contoso").

• Use semicolons to separate multiple message class names.

• Do not include standard Outlook message classes, such as "IPM.Note" or "IPM.Contact". Only include custom message classes, such as "IPM.Note.Contoso".

• Do not specify the base message class by itself (for example: "IPM").

• Do not exceed 256 characters for each message class name.

  The New Outlook Form Region wizard validates the format of your input when you click Finish.

When you complete the wizard, the New Outlook Form Region wizard applies attributes to the form region class that contain the specified message class names. You can also apply these attributes manually.

Apply class attributes

You can associate a form region with an Outlook message class after you complete the New Outlook Form Region wizard. To do this, apply attributes to the form region factory class.

The following example shows two FormRegionMessageClassAttribute attributes that have been applied to a form region factory class named myFormRegion. The first attribute associates the form region with a standard message class for a mail message form. The second attribute associates the form region with a custom message class named IPM.Task.Contoso.

<Microsoft.Office.Tools.Outlook.FormRegionMessageClass(Microsoft.Office.Tools.Outlook.FormRegionMessageClassAttribute.Note)> _
<Microsoft.Office.Tools.Outlook.FormRegionMessageClass("IPM.Task.Contoso")> _
<Microsoft.Office.Tools.Outlook.FormRegionName("Trin_Outlook_FR_Attributes.FormRegion1")> _
Partial Public Class FormRegion1Factory

' Occurs before the form region is initialized.
' To prevent the form region from appearing, set e.Cancel to true.
' Use e.OutlookItem to get a reference to the current Outlook item.
    Private Sub FormRegion1Factory_FormRegionInitializing(ByVal sender As Object, ByVal e As Microsoft.Office.Tools.Outlook.FormRegionInitializingEventArgs) Handles Me.FormRegionInitializing

End Sub

[Microsoft.Office.Tools.Outlook.FormRegionMessageClass
    (Microsoft.Office.Tools.Outlook.FormRegionMessageClassAttribute.Note)]
[Microsoft.Office.Tools.Outlook.FormRegionMessageClass
    ("IPM.Task.Contoso")]
[Microsoft.Office.Tools.Outlook.FormRegionName
    ("Trin_Outlook_FR_Attributes.FormRegion1")]
public partial class FormRegion1Factory
{
    // Occurs before the form region is initialized.
    // To prevent the form region from appearing, set e.Cancel to true.
    // Use e.OutlookItem to get a reference to the current Outlook item.
    private void FormRegion1Factory_FormRegionInitializing(object sender, 
        Microsoft.Office.Tools.Outlook.FormRegionInitializingEventArgs e)
    {
    }
}

Attributes must comply with the following guidelines:

• For custom message classes, use the fully qualified message class name (for example: "IPM.Note.Contoso").

• Do not specify the base message class by itself (for example: "IPM").

• Do not exceed 256 characters for each message class name.

• Do not include the names of standard message classes if the form region replaces the whole form or the default page of a form. You can specify standard message class names only for forms that add a new page to a form or that are appended to the bottom of a form. For more information, see How to: Add a form region to an Outlook Add-in project.

  Visual Studio validates the format of the message class names when you build the project.

See also

• Access a form region at run time
• Create Outlook form regions
• Walkthrough: Design an Outlook form region
• Guidelines to create Outlook form regions
• Form name and message class overview
• How Outlook forms and items work together