In this article we can explore how to protect a list from being deleted by the user. In real-world scenarios there are chances that the user can use the List Settings > Delete list option.
We have to ensure that the preceding option is hidden for the user through SharePoint user interface.
There are multiple ways to do this:
- Use Visual Studio to make the list property AllowDeletion to false
- Use PowerShell to make the list property AllowDeletion to false
- Create a new Permission with Delete Restriction on List and assign to the user
Here we are using the Visual Studio and PowerShell approach to disable the Delete option.
Visual Studio Approach
Create a new list in your SharePoint site and name the list as New List. Ensure that through the List Settings page you can see the Delete this list link.
Now create a new console application inside Visual Studio and name it as AllowDeletionFalse.
Inside the code modify the Main as follows:
The method is as shown below:
static void Main(string args)
SPSite site = new SPSite("http://localhost");
SPWeb web = site.OpenWeb();
SPList list = web.Lists["New List"];
list.AllowDeletion = false;
The code above connects to the URL specified, gets the instance of the list named New List and modifies the property AllowDeletion to false.
Build and execute the application. If it executed without errors the list now has the Delete link hidden. You can verify this by going back to the List Settings page inside SharePoint.
From the Permissions and Management group you will see that the Delete this list link is missing. This makes our list protected from unwanted delete activity by a user.
Now we can try to reverse the AllowDeletion property using PowerShell script. Please note that for these types of scenarios on client locations PowerShell would be more handy. (Visual Studio might not be installed in the customer premises.)
You can start the PowerShell Editor aka ISE (Integrated Script Editor) from Start > Programs > Accessories > Windows Power Shell menu group.
The editor is shown below. Save the default file as AllowDeletionFalse.ps1. (ps1 is the extension for PowerShell scripts.)
The following is the same as shown above in the .ps1 file:
If ((Get-PSSnapIn -Name Microsoft.SharePoint.PowerShell -ErrorAction SilentlyContinue) -eq $null )
Add-PSSnapIn -Name Microsoft.SharePoint.PowerShell
$web = Get-SPWeb -Identity "http://localhost" -AssignmentCollection $assignment
$list = $web.lists["New List"]
$list.AllowDeletion = $true
The first If block make sure that the Microsoft.SharePoint.PowerShell snap-in is loaded in to memory. (It is similar to add reference in Visual Studio.)
The Get-SPWeb cmdlet retrieves the reference to specified web application. The web.lists returns the reference to our New List. After setting the AllowDeletion to true the list is updated. You can use the Run command of the PowerShell editor to execute the code.
Once the code has executed successfully our New List should have the Delete this list link visible in the List Settings. You can refresh the List Settings page to ensure that it is restored.
In this article we have seen how to protect a list by disabling the Delete list option using Visual Studio and PowerShell. The source code is contained in the attachment.