A multivalued property is a property that can contain more than one value. For example, the BlockedRecipients property on the RecipientFilterConfig object can accept multiple recipient addresses as in the following examples:

• john@contoso.com
  
  
• kim@northwindtraders.com
  
  
• david@adatum.com
  
  

Because the BlockedRecipients property can accept more than one value, it's called a multivalued property.

For more information about objects, see Structured Data.

How you modify a multivalued property is slightly different from how you modify a property that accepts only one value. When you modify a property that accepts only a single value, you can assign a value directly to it, as in the following command:

When you use this command to provide a new value to the MaxSendSize property, the stored value is overwritten. This isn't a problem with properties that accept only one value. However, it becomes a problem with multivalued properties. For example, assume that the BlockedRecipients property on the RecipientFilterConfig property is configured to have the three values that are listed in the previous section. When you run the command Get-RecipientFilterConfig | Format-List BlockedRecipients, the following is displayed:

Now assume that you've received a request to add a new Simple Mail Transfer Protocol (SMTP) address to the blocked recipients list. You run the following command to add the new SMTP address:

When you run the Get-RecipientFilterConfig | Format-List BlockedRecipients command again, you will see the following:

This isn't what you expected. You wanted to add the new SMTP address to the existing list of blocked recipients, but instead the existing list of blocked recipients was overwritten by the new SMTP address. This is how modifying a multivalued property differs from modifying a property that accepts only a single value. When you modify a multivalued property, you must make sure that you append or remove values instead of overwriting the whole list of values. The following sections show you how to do exactly that.

To modify multivalued properties, you must understand the following concepts:

• User-Defined Variables
  
  
• Pipelining
  
  
• Syntax
  
  
• Working with Command Output
  
  

Appending a value to a multivalued property is very simple. It just takes a few extra steps. Again, assume that the BlockedRecipients property contains the values that are listed in the first section.

First, you have to retrieve the object that you want to modify and assign it to a variable. For example, use the following command to assign the RecipientFilterConfig object to the variable $Example:

If you run the command $Example | Format-List BlockedRecipients, the following is returned:

Next, you have to add the value that you want to append to the BlockedRecipients property on the object that is stored in the variable $Example. Be aware that this step only adds the value to the object that is stored in the variable. To add chris@contoso.com to the BlockedRecipients property on the object that is stored in the variable $Example, run the following command:

If you run the command $Example | Format-List BlockedRecipients again, the following is returned:

As you can see, the SMTP address chris@contoso.com has been added to the list of values that are stored in the BlockedRecipients property.

Finally, you have to save the object that is stored in $Example by using the following command:

Now, when you run the Get-RecipientFilterConfig | Format-List BlockedRecipients command, you will see that the SMTP address chris@contoso.com has been added to the server.

Appending Multiple Values to a Multivalued Property

Chances are that you may want to remove only one value from a multivalued property instead of removing all the values at the same time. Removing a value from a multivalued property is like appending a value. However, unlike appending values, you must remove values one at a time. Again, assume that the BlockedRecipients property contains the values that are listed in the first section.

First, you must assign the object that you want to modify to a variable, as in the following example:

Then, run the following command, which specifies the exact value that you want to remove:

Finally, save the object that is stored in the variable as follows:

The following Exchange Management Shell procedures are examples of how to append values to some of the multivalued properties that are available on various objects in Microsoft Exchange Server 2007.

To append an SMTP address to a mailbox

1. Run the following commands:

   	Copy Code
   $Mailbox = Get-Mailbox "Kim Akers" $Mailbox.EmailAddresses += "kim@contoso.com" Set-Mailbox "Kim Akers" -EmailAddresses $Mailbox.EmailAddresses

2. Run the following command to view the updated mailbox:

   	Copy Code
   Get-Mailbox "Kim Akers" | Format-List Name, EmailAddresses

To append additional delivery status notification (DSN) codes on the GenerateCopyOfDSNFor property

1. Run the following commands:

   	Copy Code
   $DsnList = Get-TransportConfig $DsnList.GenerateCopyOfDSNFor += "5.4.7", "5.7.1", "5.7.2" Set-TransportConfig -GenerateCopyOfDSNFor $DsnList.GenerateCopyOfDSNFor

2. Run the following command to view the updated DSN codes:

   	Copy Code
   Get-TransportConfig | Format-List GenerateCopyOfDSNFor

The following procedures are examples of how to remove values from some of the multivalued properties that are available on various objects in Exchange 2007.

To remove the device ID of an enabled Exchange ActiveSync device from a Client Access server (CAS) mailbox

1. Run the following commands

   	Copy Code
   $CasDevice = Get-CasMailbox "David Simpson" $CasDevice.ActiveSyncAllowedDeviceIDs -= "4B9207650054767AD0AEE83A414BCD7F" Set-CasMailbox "David Simpson" -ActiveSyncAllowedDeviceIDs $CasDevice.ActiveSyncAllowedDeviceIDs

2. Run the following command to view the updated CAS mailbox:

   	Copy Code
   Get-CasMailbox "David Simpson" | Format-List Name, ActiveSyncAllowedDeviceIDs

To remove a mailbox from the list of mailboxes that are granted "send on behalf of" permissions on a distribution group

1. Run the following command:

   	Copy Code
   $DistributionGroup = Get-DistributionGroup "Sales Group" $DistributionGroup.GrantSendOnBehalfTo -= (Get-Maibox "Christine Hughes").Identity Set-DistributionGroup "Sales Group" -GrantSendOnBehalfTo $DistributionGroup.GrantSendOnBehalfTo

2. Run the following command to view the updated distribution group

   	Copy Code
   Get-DistributionGroup "Sales Group" | Format-List Name, GrantSendOnBehalfTo

For more information about the features discussed in this topic, see the following topics:

• Configuring Recipient Filtering
  
  
• Managing User Mailboxes
  
  
• How to Copy NDRs to a Mailbox
  
  
• Managing Exchange ActiveSync Devices
  
  
• Managing Distribution Groups
  
  
• Managing Message Size Limits
  
  
• Managing Transport Rules
  
  
• Get-TransportConfig
  
  
• Set-TransportConfig
  
  
• Get-RecipientFilterConfig
  
  
• Set-RecipientFilterConfig
  
  
• Get-Mailbox
  
  
• Set-Mailbox
  
  
• Get-CASMailbox
  
  
• Set-CASMailbox
  
  
• Get-DistributionGroup
  
  
• Set-DistributionGroup