StreamReader Help

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TechieMom

I have the following code:

Dim oFile As Stream

Dim oReader As StreamReader

Dim strCarName

oFile =
[Assembly].GetExecutingAssembly.GetManifestResourceStream("Assignment3.Vehicles.txt")

oReader = New StreamReader(oFile)



For Each strCarName In oReader.ReadLine

lstCarSpecs.Items.Add(strCarName)

Next



When it reads the text file it reads only the 1st line and displays it
as follows:

B
o
n
n
e
v
i
l
l
e

I thought the readline would read until a carriage return.

Help??

Melanie
 
Hi TechieMom,
I thought the readline would read until a carriage return.
Click to expand...
Yes, that is right. And you iterate through that line and print each
character on screen. The result is what expected.

If you want to read all lines and print each line on screen, use
something like following:
strCarName = oReader.ReadLine()
Do Until strCarName Is Nothing
Console.WriteLine(strCarName)
strCarName = oReader.ReadLine()
Loop

Regards,
Thi
 
Melanie,

And what is wrong with this?

The program has now probably assumed that "strCarName" is from the Type
Char, what would be the most normal in this instruction.
For Each strCarName In oReader.ReadLine
lstCarSpecs.Items.Add(strCarName)
Next
Click to expand...

To prevent this, set option Strict On in top of your program,

I hope this helps,

Cor
 
TechieMom said:
Dim oFile As Stream

Dim oReader As StreamReader

Dim strCarName

oFile =
[Assembly].GetExecutingAssembly.GetManifestResourceStream("Assignment3.Vehicles.txt")

oReader = New StreamReader(oFile)



For Each strCarName In oReader.ReadLine

lstCarSpecs.Items.Add(strCarName)

Next
Click to expand...

The problem with your code is that you are looping through the first line's
characters instead of looping through the lines:

Reading a text file line-by-line or blockwise with a progress indicator
<URL:http://dotnet.mvps.org/dotnet/faqs/?id=readfile&lang=en>
 
Melanie,

What you wanted to do was probably
oReader = New StreamReader(oFile)
Click to expand...
dim myfile as string = oReader.ReadToEnd
For Each strCarName as String In myFile
lstCarSpecs.Items.Add(strCarName)
Next
Click to expand...

I hope this helps,

Cor
 
TechieMom said:
I have the following code:

Dim oFile As Stream
Dim oReader As StreamReader
Dim strCarName
oFile = [Assembly].GetExecutingAssembly.GetManifestResourceStream("Assignment3.Vehicles.txt")
oReader = New StreamReader(oFile)
For Each strCarName In oReader.ReadLine
lstCarSpecs.Items.Add(strCarName)
Next

When it reads the text file it reads only the 1st line and displays it
as follows:

B
o
n
n
e
v
i
l
l
e

I thought the readline would read until a carriage return.
Click to expand...

It does, but you're treating ReadLine as if it returns a
collection of strings. It doesn't, it returns just one string.
And because you haven't specified the type of strCarName
it's being treating as a Char type since a string is collection
of Chars--so you're effectively looping through each
character of the one string.

Also, remember to initialise all variables before using
them. Normally you'd initialise them to Nothing.

Finally, file processing should employ structured
error-trapping (Try..Catch...Finally).

Amend your code as follows:

' Initialise variables
Dim oFile As Stream = Nothing
Dim oReader As StreamReader = Nothing
Dim strCarName As String = Nothing

Try
' Open streams -- may cause exception
oFile = [Assembly].GetExecutingAssembly.GetManifestResourceStream("Assignment3.Vehicles.txt")
oReader = New StreamReader(oFile)

' If you get this far, the streams are open
' and can be processed.

' Peek the next character in the file (don't
' process it). If it's (-1) you've reached the
' end of the file, otherwise keep reading
' strings.
While oReader.Peak > (-1)
strCarName = oReader.ReadLine
lstCarSpecs.Items.Add(strCarName)
End While
Catch Ex as System.Exception
' Handle errors
' E.g, display a friendly message.
Finally
strCarName = Nothing
End Try

Try
' oReader may not be open
oReader.Close()
Catch Ex As System.Exception
' Ignore error
Finally
oReader = Nothing
End Try

Try
' oFile may not be open
oFile.Close()
Catch Ex As System.Exception
' Ignore error
Finally
oFile = Nothing
End Try

' Note: The Finally clauses are optional.
' Garbage collection will take care of
' tidying up for you, but it's best to do
' your own cleanup. It's simply good
' programming etiquette.
 
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