CertificateCloudCredentials credential = new CertificateCloudCredentials("{subscriptionId}","{managementCertificate}");
var sqlManagement = new SqlManagementClient(credential);
var result = sqlManagement.Dac.Export("{serverName}", new DacExportParameters()
{
    BlobCredentials = new DacExportParameters.BlobCredentialsParameter()
    {
        StorageAccessKey = "{storage-account-accesskey}",
        Uri = new Uri("https://{storage-accountname}.blob.core.windows.net/{container-name}")
    },
    ConnectionInfo = new DacExportParameters.ConnectionInfoParameter()
    {
        DatabaseName = "{dbname}",
        ServerName = "{serverName}.database.windows.net",
        UserName = "{username}",
        Password = "{password}"
    }
});