Returns a reference to a blob with the specified address, and with the specified snapshot timestamp, if the blob is a snapshot. Namespace: Microsoft.WindowsAzure.StorageClient
Assembly: Microsoft.WindowsAzure.StorageClient (in Microsoft.WindowsAzure.StorageClient.dll)
Usage
| Visual Basic |
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Dim instance As CloudBlobClient Dim blobAddress As String Dim snapshotTime As Nullable(Of DateTime) Dim returnValue As CloudBlob returnValue = instance.GetBlobReference(blobAddress, snapshotTime) |
Syntax
| Visual Basic |
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Public Function GetBlobReference ( _ blobAddress As String, _ snapshotTime As Nullable(Of DateTime) _ ) As CloudBlob |
| C# |
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public CloudBlob GetBlobReference ( string blobAddress, Nullable<DateTime> snapshotTime ) |
| C++ |
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public: CloudBlob^ GetBlobReference ( String^ blobAddress, Nullable<DateTime> snapshotTime ) |
| J# |
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| JScript |
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Parameters
- blobAddress
Type: System.String
The absolute URI to the blob, or a relative URI beginning with the container name.
- snapshotTime
Type: System.Nullable
The snapshot timestamp, if the blob is a snapshot.
Return Value
Type: Microsoft.WindowsAzure.StorageClient.CloudBlobA reference to a blob.Example
The following code example demonstrates how to get a blob snapshot using the GetBlobReference(String,Generic Nullable)method to revert changes to a blob.
| C# | Copy Code |
|---|---|
static void SnapshotExample(Uri blobEndpoint, string accountName, string accountKey)
{
//Create service client for credentialed access to the Blob service.
CloudBlobClient blobClient = new CloudBlobClient(blobEndpoint,
new StorageCredentialsAccountAndKey(accountName, accountKey));
//Get a reference to a blob and populate it with example data.
CloudBlob myBlob = blobClient.GetBlobReference("mycontainer/myblob.txt");
myBlob.UploadText("Example data.");
// Create a snapshot of the blob.
CloudBlob blobSnapshot1 = myBlob.CreateSnapshot();
// Modify the example blob with a change to be reverted.
myBlob.UploadText("Example change to be discarded.");
// Revert the change by copying the contents of the snapshot blob back into the original.
myBlob.CopyFromBlob(blobClient.GetBlobReference(blobSnapshot1.Uri.ToString(),blobSnapshot1.Attributes.Snapshot));
}
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Remarks
The GetBlobReference method returns a reference to the named blob, but it does not indicate whether the blob exists, as it does not make a round-trip to the service. If you need to ascertain the blob's existence, call a method such as FetchAttributes, and handle the resulting StorageClientException in the event the blob does not exist. The FetchAttributes method executes a HEAD request to populate the blob's properties and metadata and as such is a lightweight option for determining whether the blob exists.