Read existing messages from a Subscription/Topic in Azure ServiceBus - .net-core

Question

I am trying to read all existing messages on an Azure ServiceBus Subscription, using the Microsoft.Azure.ServiceBus.dll (in .Net Core 2.1) but am struggling.
I've found many examples that the following should work, but it doesn't:
var client = new SubscriptionClient(ServiceBusConnectionString, topicName, subscription, ReceiveMode.PeekLock, null);
var totalRetrieved = 0;
while (totalRetrieved < count)
{
var messageEnumerable = subscriptionClient.PeekBatch(count);
//// ... code removed from this example as not relevant
}
My issue is that the .PeekBatch method isn't available, and I'm confused as to how I need to approach this.
I've downloaded the source for the ServiceBusExplorer from GitHub (https://github.com/paolosalvatori/ServiceBusExplorer) and the above code example is pretty much as it's doing it. But not in .Net Core / Microsoft.Azure.ServiceBus namespace.
For clarity though, I'm trying to read messages that are already on the queue - I've worked through other examples that create listeners that respond to new messages, but I need to work in this disconnected manner, after the message has already been placed on the queue.

Answer 1

ServiceBusExplorer uses WindowsAzure.ServiceBus Library, which is a .Net Framework Library and you cannot use it in .Net Core applications. You should use Microsoft.Azure.ServiceBus (.Net Standard Library) in .Net Core applications.
Check here for samples of Microsoft.Azure.ServiceBus

Answer 2

var client = new SubscriptionClient(ServiceBusConnectionString, topicName, subscription, ReceiveMode.PeekLock, null);
client .RegisterMessageHandler(
async (message, token) =>
{
await subscriptionClient.CompleteAsync(message.SystemProperties.LockToken);
}
);
Try using RegisterMessageHandler. It will
receive messages continuously from the entity. It registers a message handler and
begins a new thread to receive messages. This handler is awaited
on every time a new message is received by the receiver.