Q: I need to change a property bag value that appears at the SharePoint list level. I understand that the SharePoint list doesn’t contain a Properties collection. How could this have happened, and how can I change the value for an existing list?

Problem: The SPList object doesn’t contain a property bag. However, a property was assigned indirectly to a list through the RootFolder object through an Elements.xml file in a list instance.

Specifically, the elements XML of a list named List01 could contain the following property named property01 with a value of value01 inside of the Elements element:

<PropertyBag Url="List01" ParentType="Folder" RootWebOnly="FALSE"

xmlns="http://schemas.microsoft.com/sharepoint/">

<Property Name="property01" Value="value01" Type="string" />

</PropertyBag>

You need to assign a different value to value01 using Windows PowerShell.

Solution: From the SharePoint 2010 Management Shell, get the RootFolder of the list and update the property:

# get the web01 web containing list01 in the example contoso web

application

$web = get-spweb -site "http://www.contoso.com/sites/web01"

# get the list, list01

$list = $web.Lists["List01"]

# get the RootFolder of the list

$root = $list.RootFolder

# set the value of property property01 to value02

$root.Properties.property01 = "value02"

# save the rootfolder change

$root.Update()

# dispose of the web

$web.Dispose() 

Here’s a related problem and solution:

Problem: You need to add a property key and value to a list, but a list doesn't contain a property bag.

Solution: Assign a new key value pair to the rootfolder of the list:

# get the web01 web containing list01 in the example contoso web

application

$web = get-spweb -site "http://www.contoso.com/sites/web01"

# get the list, list01

$list = $web.Lists["List01"]

# get the RootFolder of the list

$root = $list.RootFolder

# create a new key value pair and assign it to the root folder

$root.Properties.Add("property04", "value04")

# save the change

$root.Update()

# dispose of the web

$web.Dispose()