File Sharing on File.ReadAllText

[Jerry Spence1]

I'm doing:

Dim Contents() As String = System.IO.File. ReadAllLines("C :\MyFile.txt") with
upwards of 100,000 lines.
This is a brilliantly simple and fast way of creating an array from a text
file. However, it seems to be restricted as there are no overloads for
FileSharing (I have another application which might add to the file whilst
it is being read). The only alternative I have found is using a large amount
of looping with StreamReader which takes forever.

Is there another way?

-Jerry

[kimiraikkonen]

Re: File Sharing on File.ReadAllTex t

On Sep 22, 10:02 am, "Jerry Spence1" <1...@dfgh.comw rote:

I'm doing:
>
Dim Contents() As String = System.IO.File. ReadAllLines("C :\MyFile.txt")w ith
upwards of 100,000 lines.
This is a brilliantly simple and fast way of creating an array from a text
file. However, it seems to be restricted as there are no overloads for
FileSharing (I have another application which might add to the file whilst
it is being read). The only alternative I have found is using a large amount
of looping with StreamReader which takes forever.
>
Is there another way?
>
-Jerry

Look at this thread to consider shared access explicty:

http://groups.google.com/group/microsoft.public.dotnet.languages.vb/browse_thread/thread/1d0162123bfd6893/f6190e9b741688bb?hl=en&lnk=gst&q=stream+shared+access#f6190e9b741688bb

HTH,

Onur Güzel

[Chris Dunaway]

Re: File Sharing on File.ReadAllTex t

On Sep 22, 2:02 am, "Jerry Spence1" <1...@dfgh.comw rote:

I'm doing:
>
Dim Contents() As String = System.IO.File. ReadAllLines("C :\MyFile.txt") with
upwards of 100,000 lines.
This is a brilliantly simple and fast way of creating an array from a text
file. However, it seems to be restricted as there are no overloads for
FileSharing (I have another application which might add to the file whilst
it is being read). The only alternative I have found is using a large amount
of looping with StreamReader which takes forever.
>
Is there another way?
>
-Jerry

I'm not sure why you think a StreamReader would any slower than
calling ReadAllLines. Here is the code for the ReadAllLines method:

Public Shared Function ReadAllLines(By Val path As String, ByVal
encoding As Encoding) As String()
Dim list As New ArrayList
Using reader As StreamReader = New StreamReader(pa th, encoding)
Dim str As String
Do While (Not str = reader.ReadLine Is Nothing)
list.Add(str)
Loop
End Using
Return DirectCast(list .ToArray(GetTyp e(String)), String())
End Function

As you can see, it is using a StreamReader.

Chris

[Jerry Spence1]

Re: File Sharing on File.ReadAllTex t


"Chris Dunaway" <dunawayc@gmail .comwrote in message
news:6037dcba-5f72-4d58-9062-50ac837168c5@m7 3g2000hsh.googl egroups.com...

On Sep 22, 2:02 am, "Jerry Spence1" <1...@dfgh.comw rote:

>I'm doing:
>>
>Dim Contents() As String = System.IO.File. ReadAllLines("C :\MyFile.txt")
>with
>upwards of 100,000 lines.
>This is a brilliantly simple and fast way of creating an array from a
>text
>file. However, it seems to be restricted as there are no overloads for
>FileSharing (I have another application which might add to the file
>whilst
>it is being read). The only alternative I have found is using a large
>amount
>of looping with StreamReader which takes forever.
>>
>Is there another way?
>>
>-Jerry

>
I'm not sure why you think a StreamReader would any slower than
calling ReadAllLines. Here is the code for the ReadAllLines method:
>
Public Shared Function ReadAllLines(By Val path As String, ByVal
encoding As Encoding) As String()
Dim list As New ArrayList
Using reader As StreamReader = New StreamReader(pa th, encoding)
Dim str As String
Do While (Not str = reader.ReadLine Is Nothing)
list.Add(str)
Loop
End Using
Return DirectCast(list .ToArray(GetTyp e(String)), String())
End Function
>
As you can see, it is using a StreamReader.
>
Chris

Thanks Chris. I believed it would be slower because you are looping round
the Do While loop, and the System.File.Rea dAllLines happens in one line - no
looping. However, I've just experimented with 1million lines and there
doesn't seem to be that much difference, so I guess this is what
System.File.Rea dAllLines does behind the scenes. However, I can't find a way
of setting the FileShare using StreamReader which is what I need.

-Jerry

[Chris Dunaway]

Re: File Sharing on File.ReadAllTex t

On Sep 22, 5:27 pm, "Jerry Spence1" <1...@dfgh.comw rote:

System.File.Rea dAllLines does behind the scenes. However, I can't find a way
of setting the FileShare using StreamReader which is what I need.

Just use a FileStream to open the file and use a streamreader to read
it:

Using fs As New FileStream("fil ename.txt", FileMode.Append ,
FileAccess.Read Write, FileShare.ReadW rite)
Using rdr As New StreamReader(fs )
'User streamreader here...
End Using
End Using

Chris