[BUG] Can not set PrefixMatch on ManagementPolicyFilter

Describe the bug Can not set PrefixMatch on ManagementPolicyFilter

Expected behavior Able to set PrefixMatch on ManagementPolicyFilter, either via construction or public property

Actual behavior (include Exception or Stack Trace) What is the actual behavior? Not able to set PrefixMatch on ManagementPolicyFilter, either via construction or public property. Please refer to following source code

public class ManagementPolicyFilter : IUtf8JsonSerializable
{
 public ManagementPolicyFilter(IEnumerable<string> blobTypes);
 public IList<string> PrefixMatch { get; }
}

To Reproduce Steps to reproduce the behavior (include a code snippet, screenshot, or any additional information that might help us reproduce the issue)

Use following code to create ManagementPolicyRule instance, failed can not set PrefixMatch

    var rules = new List<ManagementPolicyRule>();
    var rule1 = new ManagementPolicyRule("DeleteLongerThan24Hours", RuleType.Lifecycle, 
        new ManagementPolicyDefinition(new ManagementPolicyAction {BaseBlob = new ManagementPolicyBaseBlob(){ Delete =new DateAfterModification(1)},})
        {
            Filters = new ManagementPolicyFilter(new List<string> { "blockBlob" })
            {
                PrefixMatch = new List<string> { "upload" }
            }
        });
    rules.Add(rule1);

Environment:

• Name and version of the Library package used: [e.g. Azure.Storage.Blobs 12.2.0] azure.resourcemanager.storage 1.0.0-preview.2
• Hosting platform or OS and .NET runtime version (dotnet --info output for .NET Core projects): [e.g. Azure AppService or Windows 10 .NET Framework 4.8] Windows 10, DotNet Core
• IDE and version : [e.g. Visual Studio 16.3] VS version does not matter

[ArcturusZhang]

Hi @blrchen please try this:

    var rules = new List<ManagementPolicyRule>();
    var rule1 = new ManagementPolicyRule("DeleteLongerThan24Hours", RuleType.Lifecycle, 
        new ManagementPolicyDefinition(new ManagementPolicyAction {BaseBlob = new ManagementPolicyBaseBlob(){ Delete =new DateAfterModification(1)},})
        {
            Filters = new ManagementPolicyFilter(new List<string> { "blockBlob" })
            {
                PrefixMatch = { "upload" }
            }
        });
    rules.Add(rule1);

Please note since the property PrefixMatch is unassignable, you cannot construct a new list and assign to that property. The SDK will initialize this property with a built-in List type, and the fact of no-setter could ensure you cannot change the list to another instance. The usage above is a C# grammar sugar of the collection initialization, check out more information here: https://docs.microsoft.com/en-us/dotnet/csharp/programming-guide/classes-and-structs/object-and-collection-initializers#object-initializers-with-collection-read-only-property-initialization

[blrchen]

This works, thanks man.