# AzureServiceBusTopicResource Properties

- Package: [Aspire.Hosting.Azure.ServiceBus](/reference/api/csharp/aspire.hosting.azure.servicebus.md)
- Type: [AzureServiceBusTopicResource](/reference/api/csharp/aspire.hosting.azure.servicebus/azureservicebustopicresource.md)
- Kind: `Properties`
- Members: `6`

Represents a Service Bus Topic. Initializes a new instance of the [AzureServiceBusTopicResource](/reference/api/csharp/aspire.hosting.azure.servicebus/azureservicebustopicresource.md) class.

## ConnectionStringExpression

- Name: `ConnectionStringExpression`
- Modifiers: `get`
- Returns: `ReferenceExpression`
- Source: [GitHub](https://github.com/microsoft/aspire/blob/cbc352350f1a9bafbaff10d14a2c8de4ac186a48/src/Aspire.Hosting.Azure.ServiceBus/AzureServiceBusTopicResource.cs#L47)

Gets the connection string expression for the Azure Service Bus Topic.

```csharp
public ReferenceExpression ConnectionStringExpression { get; }
```

## DefaultMessageTimeToLive

- Name: `DefaultMessageTimeToLive`
- Modifiers: `nullable` `get; set`
- Returns: `TimeSpan?`
- Source: [GitHub](https://github.com/microsoft/aspire/blob/cbc352350f1a9bafbaff10d14a2c8de4ac186a48/src/Aspire.Hosting.Azure.ServiceBus/AzureServiceBusTopicResource.cs)

ISO 8601 default message timespan to live value. This is the duration after which the message expires, starting from when the message is sent to Service Bus. This is the default value used when TimeToLive is not set on a message itself.

```csharp
public TimeSpan? DefaultMessageTimeToLive { get; set; }
```

## DuplicateDetectionHistoryTimeWindow

- Name: `DuplicateDetectionHistoryTimeWindow`
- Modifiers: `nullable` `get; set`
- Returns: `TimeSpan?`
- Source: [GitHub](https://github.com/microsoft/aspire/blob/cbc352350f1a9bafbaff10d14a2c8de4ac186a48/src/Aspire.Hosting.Azure.ServiceBus/AzureServiceBusTopicResource.cs)

ISO 8601 timeSpan structure that defines the duration of the duplicate detection history. The default value is 10 minutes.

```csharp
public TimeSpan? DuplicateDetectionHistoryTimeWindow { get; set; }
```

## Parent

- Name: `Parent`
- Modifiers: `get`
- Returns: [AzureServiceBusResource](/reference/api/csharp/aspire.hosting.azure.servicebus/azureservicebusresource.md)
- Source: [GitHub](https://github.com/microsoft/aspire/blob/cbc352350f1a9bafbaff10d14a2c8de4ac186a48/src/Aspire.Hosting.Azure.ServiceBus/AzureServiceBusTopicResource.cs#L42)

Gets the parent Azure Service Bus resource.

```csharp
public AzureServiceBusResource Parent { get; }
```

## RequiresDuplicateDetection

- Name: `RequiresDuplicateDetection`
- Modifiers: `nullable` `get; set`
- Returns: `bool?`
- Source: [GitHub](https://github.com/microsoft/aspire/blob/cbc352350f1a9bafbaff10d14a2c8de4ac186a48/src/Aspire.Hosting.Azure.ServiceBus/AzureServiceBusTopicResource.cs)

A value indicating if this topic requires duplicate detection.

```csharp
public bool? RequiresDuplicateDetection { get; set; }
```

## TopicName

- Name: `TopicName`
- Modifiers: `get; set`
- Returns: `string`
- Source: [GitHub](https://github.com/microsoft/aspire/blob/cbc352350f1a9bafbaff10d14a2c8de4ac186a48/src/Aspire.Hosting.Azure.ServiceBus/AzureServiceBusTopicResource.cs)

The topic name.

```csharp
public string TopicName { get; set; }
```