asked on

Copy A File Using Async

How do you copy a file Async using the following code? It appears to only work with Non-Binary files (.txt, etc.). I'd like to be able to copy any kind of file.

Shared Async Function CopyFile(inSourceFile As String,
inTargetFolder As String,
Optional inRetainDateTime As Boolean = True) As Task
ExceptionThrown = False
ExceptionDefinition = ""

Dim TargetFile As String = inTargetFolder + "\" + GSFileInfo.ParseFileName(inSourceFile, False)
Dim SourceDateTime As Date = File.GetLastWriteTime(inSourceFile)

Try
Using SourceStream As FileStream = File.Open(inSourceFile, FileMode.Open)
Using DestinationStream As FileStream = File.Create(TargetFile)
Await SourceStream.CopyToAsync(DestinationStream)
End Using
End Using

If inRetainDateTime Then
File.SetLastWriteTime(TargetFile, SourceDateTime)
End If

Catch ex As Exception
ExceptionThrown = True
ExceptionDefinition = ex.Message
End Try
End Function

ASKER CERTIFIED SOLUTION

Michael Pfister

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See answer

RayT

ASKER

It looks like BinaryReader/BinaryWriter is what I need. Can you show me an example copy FileA To FileB?

Michael Pfister

Using filestream should be better:

https://stackoverflow.com/questions/39591579/how-to-use-filestream-for-copying-files-in-c-sharp

RayT

ASKER

Thanks

louisfr

File.Open is used for text files

That is not true. Were you thinking about File.OpenText ?

RayT

ASKER

I simply want to async copy a file from FolderA to FolderB. And can this be done without throwing File Administrator Permission errors?

Michael Pfister

File Administrator Permission errors are not caused by the function used.
Its a permission issue you'll have as well when you copy the file via Windows explorer

louisfr

You might need to have the program ask for administrator privilege by adding this line to your manifest:

<requestedExecutionLevel  level="requireAdministrator" uiAccess="false" />

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RayT

ASKER

Where exactly should this code appear?

louisfr

If you don't have an app.manifest file in your project, create it (right-click on the project, add > new item, and select Application Manifest File).
The file should already include a line like this:

<requestedExecutionLevel level="asInvoker" uiAccess="false" />

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Replace "asInvoker" with "requireAdministrator".

it_saige

It would appear in an application manifest. You can add one to your project by right clicking and choosing Add -> New Item, then select Application Manifest File from the list of addable files.

HTH,

-saige-

RayT

ASKER

It still does not work. It appears that I need to set the permissions on the target drive to administrator. How do i do that?

louisfr

If you try copying a file in the explorer, does it work?

RayT

ASKER

I found out what the problem was. The rights on the target drive was set for read only. The program started working fine once i changed the rights to read/write. I also switched the code to something more robust Robocopy.