How to: Display Custom Task Panes with E-Mail Messages in Outlook

The following code displays a unique custom task pane in the Inspector window of every e-mail message that is opened. For more information, including instructions for using the code examples in this topic, see Walkthrough: Displaying Custom Task Panes with E-Mail Messages in Outlook.

The following code examples provide the complete contents of the following add-in project files:

• The Ribbon.xml file.

• The Ribbon.cs or Ribbon.vb file.

• The ThisAddIn.cs or ThisAddIn.vb file.

• Replace the contents of the Ribbon.xml file in your add-in with the following XML.

  <customUI xmlns="https://schemas.microsoft.com/office/2006/01/customui" onLoad="OnLoad">
    <ribbon>
      <tabs>
        <tab idMso="TabAddIns">
          <group id="MyGroup"
                 label="Task Pane">
            <toggleButton id="toggleTaskPane"
                          size="large"
                          label="Show/Hide Task Pane"
                          screentip="Show/Hide Task Pane"
                          onAction="OnToggleTaskPane"
                          getPressed="GetPressedState"
                          imageMso="HappyFace" />
          </group>
        </tab>
      </tabs>
    </ribbon>
  </customUI>
  

• Replace the contents of the Ribbon.cs or Ribbon.vb file in your add-in with the following code.

  Imports System
  Imports System.Collections.Generic
  Imports System.Diagnostics
  Imports System.IO
  Imports System.Text
  Imports System.Reflection
  Imports System.Runtime.InteropServices
  Imports System.Windows.Forms
  Imports Office = Microsoft.Office.Core
  Imports Outlook = Microsoft.Office.Interop.Outlook
  Imports Microsoft.Office.Tools
  
  Partial Public Class ThisAddIn
  
      Public ribbon As Ribbon
  
      Protected Overrides Function RequestService(ByVal serviceGuid As Guid) As Object
          If serviceGuid = GetType(Office.IRibbonExtensibility).GUID Then
              If ribbon Is Nothing Then
                  ribbon = New Ribbon()
              End If
              Return ribbon
          End If
  
          Return MyBase.RequestService(serviceGuid)
      End Function
  
  End Class
  
  <ComVisible(True)> _
      Public Class Ribbon
      Implements Office.IRibbonExtensibility
  
      Private ribbon As Office.IRibbonUI
  
      Public Sub New()
      End Sub
  
  #Region "IRibbonExtensibility Members"
  
      Public Function GetCustomUI(ByVal ribbonID As String) As String Implements Office.IRibbonExtensibility.GetCustomUI
          Select Case ribbonID
              Case "Microsoft.Outlook.Mail.Read", "Microsoft.Outlook.Mail.Compose"
                  Return GetResourceText("OutlookMailItemTaskPane.Ribbon.xml")
              Case Else
                  Return String.Empty
          End Select
      End Function
  #End Region
  
  #Region "Ribbon Callbacks"
  
      Public Sub OnLoad(ByVal ribbonUI As Office.IRibbonUI)
          Me.ribbon = ribbonUI
      End Sub
  
      Public Sub OnToggleTaskPane(ByVal control As Office.IRibbonControl, ByVal isPressed As Boolean)
          Dim inspector As Outlook.Inspector = control.Context
          Dim inspectorWrapper As InspectorWrapper = Globals.ThisAddIn.inspectorWrappers(inspector)
          Dim taskPane As CustomTaskPane = inspectorWrapper.CustomTaskPane
          If Not (taskPane Is Nothing) Then
              taskPane.Visible = isPressed
          End If
      End Sub
  
      Public Function GetPressedState(ByVal control As Office.IRibbonControl) As Boolean
          Dim inspector As Outlook.Inspector = control.Context
          If Globals.ThisAddIn.inspectorWrappers.ContainsKey(inspector) Then
              Dim inspectorWrapper As InspectorWrapper = Globals.ThisAddIn.inspectorWrappers(inspector)
              Dim taskPane As CustomTaskPane = inspectorWrapper.CustomTaskPane
  
              If taskPane IsNot Nothing Then
                  Return taskPane.Visible
              Else
                  Return False
              End If
          Else
              Return False
          End If
      End Function
  
  #End Region
  
      Public Sub RefreshControl(ByVal controlID As String)
          ribbon.InvalidateControl(controlID)
      End Sub
  
      Public ReadOnly Property RibbonUI() As Office.IRibbonUI
          Get
              Return ribbon
          End Get
      End Property
  
  #Region "Helpers"
  
      Private Shared Function GetResourceText(ByVal resourceName As String) As String
          Dim asm As Assembly = Assembly.GetExecutingAssembly()
          Dim resourceNames() As String = asm.GetManifestResourceNames()
          For i As Integer = 0 To resourceNames.Length - 1
              If String.Compare(resourceName, resourceNames(i), StringComparison.OrdinalIgnoreCase) = 0 Then
                  Using resourceReader As StreamReader = New StreamReader(asm.GetManifestResourceStream(resourceNames(i)))
                      If resourceReader IsNot Nothing Then
                          Return resourceReader.ReadToEnd()
                      End If
                  End Using
              End If
          Next
          Return Nothing
      End Function
  
  #End Region
  
  End Class
  

• Replace the contents of the ThisAddIn.cs or ThisAddIn.vb file in your add-in with the following code.

  Imports System.Collections.Generic
  Imports Microsoft.Office.Tools
  
  Public Class InspectorWrapper
      Private WithEvents inspector As Outlook.Inspector
      Private WithEvents taskPane As CustomTaskPane
  
      Public Sub New(ByVal Inspector As Outlook.Inspector)
          Inspector = Inspector
          taskPane = Globals.ThisAddIn.CustomTaskPanes.Add(New TaskPaneControl(), "My task pane", Inspector)
          taskPane.Visible = True
      End Sub
  
      Sub TaskPane_VisibleChanged(ByVal sender As Object, ByVal e As EventArgs) Handles taskPane.VisibleChanged
          Globals.ThisAddIn.ribbon.RefreshControl("toggleTaskPane")
      End Sub
  
      Sub InspectorWrapper_Close() Handles inspector.Close
          If Not (taskPane Is Nothing) Then
              Globals.ThisAddIn.CustomTaskPanes.Remove(taskPane)
          End If
  
          taskPane = Nothing
          Globals.ThisAddIn.inspectorWrappers.Remove(inspector)
          RemoveHandler inspector.Close, AddressOf InspectorWrapper_Close
          inspector = Nothing
      End Sub
  
      Public ReadOnly Property CustomTaskPane() As CustomTaskPane
          Get
              Return taskPane
          End Get
      End Property
  End Class
  
  public class ThisAddIn
  
      Public inspectorWrappers As New Dictionary(Of Outlook.Inspector, InspectorWrapper)
      Private WithEvents inspectors As Outlook.Inspectors
  
      Private Sub ThisAddIn_Startup(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Startup
          inspectors = Me.Application.Inspectors
  
          Dim inspector As Outlook.Inspector
          For Each inspector In inspectors
              Inspectors_NewInspector(inspector)
          Next inspector
      End Sub
  
      Private Sub ThisAddIn_Shutdown(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Shutdown
          RemoveHandler inspectors.NewInspector, AddressOf Inspectors_NewInspector
          inspectors = Nothing
          inspectorWrappers = Nothing
      End Sub
  
      Sub Inspectors_NewInspector(ByVal Inspector As Outlook.Inspector) _
          Handles inspectors.NewInspector
  
          If TypeOf Inspector.CurrentItem Is Outlook.MailItem Then
              inspectorWrappers.Add(Inspector, New InspectorWrapper(Inspector))
  
              If ribbon IsNot Nothing AndAlso ribbon.RibbonUI IsNot Nothing Then
                  ribbon.RefreshControl("toggleTaskPane")
              End If
          End If
      End Sub
  End class
  

Walkthrough: Displaying Custom Task Panes with E-Mail Messages in Outlook
How to: Add a Custom Task Pane to an Application
How to: Customize the Ribbon

Custom Task Panes Overview
Ribbon Extensibility Overview
Outlook Object Model Overview