.NET Framework 4.7.2 WinForms读取Azure Blob时PerTypeValues`1初始化异常求助

问题详情 #

基于.NET Framework 4.7.2的WinForms应用，上传Blob到Azure存储账户功能正常，但调用OpenRead()方法流式读取Blob时，抛出错误：'PerTypeValues`1'的类型初始值设定项引发异常。

流式读取实现代码 #

Public Function StreamFileFromAzureStorageAcct(ByVal clientLocalFilePath As String, ByVal containerDestName As String, ByRef strReturn As String) As StreamReader

    Dim strReturn As String = String.Empty
    Dim textInStream As Stream = Nothing
    Dim textIn As StreamReader = Nothing
    Dim connectionString As String = Nothing

    Try

        connectionString = String.Format("DefaultEndpointsProtocol=https;AccountName={0};AccountKey={1};EndpointSuffix={2}", modConfigSettings.AzureStorageAcctName, modConfigSettings.AzureStorageAcctKey, modConfigSettings.AzureStorageAcctURL)
        Dim Container As BlobContainerClient = New BlobContainerClient(connectionString, containerDestName)

        Dim BlobClient As BlobClient = Container.GetBlobClient(Path.GetFileName(clientLocalFilePath))

        Dim readOptions As BlobOpenReadOptions = New BlobOpenReadOptions(False)
        readOptions.Position = 0

        ''Azure Storage Acct Read call returns a Stream
        textInStream = BlobClient.OpenRead(readOptions)

        '' Pass the Stream to a StreamReader to stay inline with existing code.
        textIn = New StreamReader(textInStream)

        strReturn = "Success"

        Return textIn

    Catch er As Exception
        strReturn = String.Format("Failed to Stream from Storage Account: {0}-File:{1}-connectionString: {2}-{3}", er.Message, Path.GetFileName(clientLocalFilePath), connectionString, er.StackTrace)
    End Try

    Return Nothing
End Function

捕获到的错误栈 #

从存储账户流式读取失败：'PerTypeValues`1'的类型初始值设定项引发异常。- at System.SpanHelpers.IsReferenceOrContainsReferencesT at Azure.Storage.Blobs.BlobRestClient.get_ResponseClassifier200() at Azure.Storage.Blobs.BlobRestClient.CreateGetPropertiesRequest(String snapshot, String versionId, Nullable1 timeout, String leaseId, String encryptionKey, String encryptionKeySha256, StringencryptionAlgorithm,String ifTags, RequestConditions requestConditions, RequestContext context) at Azure.Storage.Blobs.BlobRestClient.GetProperties(String snapshot, String versionId, Nullable1 timeout, String leaseId, String encryptionKey, String encryptionKeySha256, String encryptionAlgorithm, String ifTags, RequestConditions requestConditions, RequestContext context) at Azure.Storage.Blobs.Specialized.BlobBaseClient.d__124.MoveNext() --- End of stack trace from previous location where exception was throw --- at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task) atSystem.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task) atAzure.Storage.Blobs.Specialized.BlobBaseClient.d__98.MoveNext() --- End of stack trace from previous location where exception was thrown --- atSystem.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task) at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Tasktask) atAzure.Storage.Blobs.Specialized.BlobBaseClient.OpenRead(BlobOpenReadOptions options, CancellationToken cancellationToken) at DBAccessObjects.RemFredDataAdmin.StreamFileFromAzureStorageAcct(StringclientLocalFilePath, String containerDestName, String& strReturn) in C:\Users\csale\source\Workspaces\Application Server\FredServer\DBAccessObjects\RemFredDataAdmin.vb:line 15904

解决方案 #

1. 适配Azure存储SDK版本 #

.NET Framework 4.7.2对较新的Azure.Storage.Blobs SDK兼容性有限，建议降级到12.17.0及以下版本，该版本对.NET Framework支持更完善，避免SDK内部使用.NET Core专属API导致的初始化异常。

2. 补充System.Memory组件 #

错误中的SpanHelpers属于System.Memory模块，.NET Framework 4.7.2原生未完整支持，需安装System.Memory NuGet包（推荐版本4.5.4+），补充缺失的类型和方法。

3. 改用异步读取方法 #

尝试使用异步版本OpenReadAsync()替代同步调用，规避线程或初始化逻辑冲突，修改后的示例代码：

Public Async Function StreamFileFromAzureStorageAcctAsync(ByVal clientLocalFilePath As String, ByVal containerDestName As String, ByRef strReturn As String) As Task(Of StreamReader)
    Dim textInStream As Stream = Nothing
    Dim textIn As StreamReader = Nothing
    Dim connectionString As String = Nothing

    Try
        connectionString = String.Format("DefaultEndpointsProtocol=https;AccountName={0};AccountKey={1};EndpointSuffix={2}", modConfigSettings.AzureStorageAcctName, modConfigSettings.AzureStorageAcctKey, modConfigSettings.AzureStorageAcctURL)
        Dim Container As BlobContainerClient = New BlobContainerClient(connectionString, containerDestName)
        Dim BlobClient As BlobClient = Container.GetBlobClient(Path.GetFileName(clientLocalFilePath))

        ' 先检查Blob是否存在
        If Not BlobClient.Exists() Then
            strReturn = "目标Blob不存在"
            Return Nothing
        End If

        Dim readOptions As BlobOpenReadOptions = New BlobOpenReadOptions(False)
        readOptions.Position = 0

        textInStream = Await BlobClient.OpenReadAsync(readOptions)
        textIn = New StreamReader(textInStream)
        strReturn = "Success"

        Return textIn
    Catch er As Exception
        strReturn = String.Format("Failed to Stream from Storage Account: {0}-File:{1}-{2}", er.Message, Path.GetFileName(clientLocalFilePath), er.StackTrace)
        Return Nothing
    End Try
End Function

4. 前置检查Blob存在性 #

在调用读取方法前，通过BlobClient.Exists()验证目标Blob是否存在，避免因Blob不存在触发的间接初始化异常。

内容的提问来源于stack exchange，提问作者user2413934