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I have a java function, and am trying to mimic the same functionality in VB.NET.

The Java function:

String text = “ABCDEFG”
int length = text.length();
int l1 = length >> 8;
int l2 = length % 256;
swriter.write(new byte[] {(byte)l1, (byte)l2});

My VB.NET Converted function: 

Dim text As String = "ABCDEFG"
Dim length As Integer = text.Length
Dim l1 As Integer = length >> 8
Dim l2 As Integer = length Mod 256
Dim tempArr(2) As Byte
tempArr(0) = Convert.ToByte(l1)
tempArr(1) = Convert.ToByte(l2)
swriter.Write(tempArr)

swriter is a StreamWriter

What is is that everytime when I see the values written through streamwriter on the server shows as "System.byte[]". I tried using BitConverter.GetBytes() function also, but it gives the same results.

What is that I am missing? And how to write the numbers as Byte format. In the above example the length of the text is 7("ABCDEFG"), however in my application it will be more than 1000.

RBarryYoung
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Bhaskar
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    How is it not working? What's wrong with it now? – RBarryYoung Apr 29 '13 at 19:51
  • its writing as "System.byte[]" not the actual byte value, the Write function takes an object (tempArr) as parameter and its writing as Object.ToString() ..i.e tempArr.ToString() = "System.byte[]" – Bhaskar Apr 29 '13 at 20:00
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    Aside: `Convert.ToByte` => `CByte`. Avoid the `Convert` class, it’s overly verbose and generally offers no benefit over the simple cast functions. – Konrad Rudolph Apr 29 '13 at 20:11

1 Answers1

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Take a look at the documentation on the StreamWriter.Write() method. If you browse through those overloads, none of them accepts a byte array. The best match is a string, and so this compiles down to IL that will try to convert your array to a string by calling the array's .ToString() method. Since arrays do not overload the .ToString() method, you get the default implementation of the base Object type, and that just returns the type name... hence your System.byte[] result.

That makes one wonder why a StreamWriter doesn't know what to do with byte arrays. Let's check the documentation on the StreamWriter type, from which I quote:

Implements a TextWriter for writing characters to a stream in a particular encoding.

Aha! The reason there is no byte array overload is that you're using a type specifically designed for working with Text.

To fix this, you need to use a base Stream type or a BinaryWriter type, instead of StreamWriter. Either of those types are perfectly happy to work with byte arrays.

Finally, while I'm at it I need to point out that you declared your array wrong. In VB.Net, the subscript on the array declaration is the index of the last element in the array. Dim tempArr(2) As Byte declares an array with three elements, not two, with indices at 0,1, and 2.

Joel Coehoorn
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  • Thanks Joel, however I typed wrong in my code above, I used tempArr(1) for the declaration. Anyhow thanks..I will use BinaryWriter and let you know the results – Bhaskar Apr 29 '13 at 20:09
  • No worries: just about everyone gets array indexes wrong their first time in vb.net coming from other languages. – Joel Coehoorn Apr 29 '13 at 20:10