我测试了以下代码，它可以生成文件sas令牌并将文件复制到blob。

static async System.Threading.Tasks.Task Main(string[] args)
        {
            var accountName = "accountname";
            var accountKey = "your account key";
            var account = new CloudStorageAccount(new StorageCredentials(accountName,accountKey),true);
            var fileClient = account.CreateCloudFileClient();
            var share = fileClient.GetShareReference("windows");
            CloudFileDirectory rootDir = share.GetRootDirectoryReference();
            var file = rootDir.GetFileReference("test.json");

            var sasToken = file.GetSharedAccessSignature(new Microsoft.WindowsAzure.Storage.File.SharedAccessFilePolicy()
            {
                Permissions = SharedAccessFilePermissions.Read | SharedAccessFilePermissions.Write,SharedAccessExpiryTime = new DateTimeOffset(DateTime.UtcNow.AddDays(1))
            });

            var uri = file.StorageUri.PrimaryUri + sasToken;
            Uri fileuri = new Uri(uri);
            Console.WriteLine(uri);
            var blobclient = account.CreateCloudBlobClient();
            var  containerClient =blobclient.GetContainerReference("test");
            var blob=containerClient.GetBlockBlobReference("test.json");
            await blob.StartCopyAsync(fileuri);

        }

希望这可以为您提供帮助，如果仍然有其他问题，请随时告诉我。