AzureEventHubsSASTokenAndPublisher.cs

var serviceNamespace = "<SERVICE_NAMESPACE>";
var eventHubsName = "<EVENTHUBs_NAME>";
var deviceName = "myDevice";    // 認証ユーザーのIdとかをセット

// 管理ポータルで設定した共有アクセスポリシーの情報
var sharedAccessPolicyName = "<NAME>";
var sharedAccessPolicyKey = "<KEY>";

// <EVENTHUBS_NAME>/publishers/<PUBLISHER_NAME>
var resourcePath = String.Format("{0}/publishers/{1}", eventHubsName, deviceName);

// sb://<SERVICE_NAMESPACE>.servicebus.windows.net/<EVENTHUBS_NAME>/publishers/<PUBLISHER_NAME>
Uri publisherUrl = ServiceBusEnvironment.CreateServiceUri("sb", serviceNamespace, resourcePath);

// SASTokenの生成
string sas = SharedAccessSignatureTokenProvider.GetSharedAccessSignature(
    sharedAccessPolicyName, 
    sharedAccessPolicyKey,
    publisherUrl.AbsoluteUri,
    TimeSpan.FromSeconds(60));