How To: Get Outlook e-mail item’s custom properties – C# and VB.NET samples

In my previous article How To: Add a custom property to the UserProperties collection I showed you the way to add a custom property to the UserProperties collection of an e-mail item in Outlook. Now I want to demonstrate you how to iterate over all user properties of an e-mail item. The UserProperties class provides the Item method which returns a single UserProperty entry from the collection. As a parameter, the Item method expects to see either the index number or the name of the property. Please pay special attention to the fact that indexing in Office applications starts from one (not zero).

The code below iterates over all defined user properties and then shows a summary message box to the user. To get the code running, you just need to pass an instance of the MailItem class to the ShowUserProperties method.

C# and Add-in Express:

using System.Text; 
// ... 
private void ShowUserProperties(Outlook.MailItem mail) 
{ 
    Outlook.UserProperties mailUserProperties = null; 
    Outlook.UserProperty mailUserProperty = null; 
    StringBuilder builder = new StringBuilder(); 
    mailUserProperties = mail.UserProperties; 
    try 
    { 
       for (int i = 1; i < = mailUserProperties.Count; i++)
       { 
           mailUserProperty = mailUserProperties.Item(i);
           if (mailUserProperty != null)
           {
              builder.AppendFormat("Name: {0} \tValue: {1} \n\r", 
                  mailUserProperty.Name, mailUserProperty.Value); 
              Marshal.ReleaseComObject(mailUserProperty); 
              mailUserProperty = null; 
           } 
       } 
       if (builder.Length > 0) 
       { 
           System.Windows.Forms.MessageBox.Show(builder.ToString(),
               "The UserProperties collection"); 
       } 
    } 
    catch (Exception ex) 
    { 
        System.Windows.Forms.MessageBox.Show(ex.Message); 
    } 
    finally 
    { 
        if (mailUserProperties != null) 
            Marshal.ReleaseComObject(mailUserProperties); 
    } 
}

VB.NET and Add-in Express:

Imports System.Text 
' ... 
Private Sub ShowUserProperties(mail As Outlook.MailItem) 
    Dim mailUserProperties As Outlook.UserProperties = Nothing 
    Dim mailUserProperty As Outlook.UserProperty = Nothing 
    Dim builder As StringBuilder = New StringBuilder() 
    mailUserProperties = mail.UserProperties 
    Try 
        For i As Integer = 1 To mailUserProperties.Count 
            mailUserProperty = mailUserProperties.Item(i) 
            If Not IsNothing(mailUserProperty) Then 
                builder.AppendFormat("Name: {0} \tValue: {1} \n\r", _
                    mailUserProperty.Name, mailUserProperty.Value) 
                Marshal.ReleaseComObject(mailUserProperty) 
                mailUserProperty = Nothing 
             End If 
         Next 
         If (builder.Length > 0) Then 
             System.Windows.Forms.MessageBox.Show(builder.ToString(), _ 
                 "The UserProperties collection") 
         End If 
    Catch ex As Exception 
        System.Windows.Forms.MessageBox.Show(ex.Message) 
    Finally 
        If Not IsNothing(mailUserProperties) Then 
            Marshal.ReleaseComObject(mailUserProperties) 
        End If 
    End Try 
End Sub

C# and VSTO:

using System.Runtime.InteropServices; 
// ... 
private void ShowUserProperties(Outlook.MailItem mail) 
{
    Outlook.UserProperties mailUserProperties = null; 
    Outlook.UserProperty mailUserProperty = null; 
    StringBuilder builder = new StringBuilder(); 
    mailUserProperties = mail.UserProperties; 
    try 
    { 
        for (int i = 1; i < = mailUserProperties.Count; i++) 
        { 
            mailUserProperty = mailUserProperties[i]; 
            if (mailUserProperty != null) 
            { 
                builder.AppendFormat("Name: {0} \tValue: {1} \n\r", 
                    mailUserProperty.Name, mailUserProperty.Value); 
                Marshal.ReleaseComObject(mailUserProperty); 
                mailUserProperty = null; 
            } 
        } 
        if (builder.Length > 0) 
        { 
            System.Windows.Forms.MessageBox.Show(builder.ToString(), 
                 "The UserProperties collection"); 
        } 
    } 
    catch (Exception ex) 
    { 
        System.Windows.Forms.MessageBox.Show(ex.Message); 
    } 
    finally 
    { 
        if (mailUserProperties != null) 
            Marshal.ReleaseComObject(mailUserProperties); 
    } 
}

VB.NET and VSTO:

Imports System.Text 
Imports System.Runtime.InteropServices 
' ... 
Private Sub ShowUserProperties(mail As Outlook.MailItem)
    Dim mailUserProperties As Outlook.UserProperties = Nothing 
    Dim mailUserProperty As Outlook.UserProperty = Nothing 
    Dim builder As StringBuilder = New StringBuilder() 
    mailUserProperties = mail.UserProperties 
    Try 
        For i As Integer = 1 To mailUserProperties.Count 
            mailUserProperty = mailUserProperties.Item(i) 
            If Not IsNothing(mailUserProperty) Then 
                builder.AppendFormat("Name: {0} \tValue: {1} \n\r", _ 
                    mailUserProperty.Name, mailUserProperty.Value) 
                Marshal.ReleaseComObject(mailUserProperty) 
                mailUserProperty = Nothing 
            End If 
        Next 
        If (builder.Length > 0) Then 
            System.Windows.Forms.MessageBox.Show(builder.ToString(), _ 
                "The UserProperties collection") 
        End If 
    Catch ex As Exception 
        System.Windows.Forms.MessageBox.Show(ex.Message) 
    Finally 
        If Not IsNothing(mailUserProperties) Then 
            Marshal.ReleaseComObject(mailUserProperties) 
        End If 
    End Try 
End Sub

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