Re: Why BinaryReader don't have the EOF property - C# Discussion Boards

5-Oct-05 16:04

Why if XmlReader has an EOF property, the BinaryReader doesn't have it?

I don't like this, you can read why in my blog:
The EOF Issue[^]

How do you solve this issue?

Confused | :confused:

Eduardo Diaz

site | english blog | spanish blog

Guffa5-Oct-05 19:23

Guffa

5-Oct-05 19:23

Use the ReadBytes method.

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b { font-weight: normal; }

ediazc6-Oct-05 5:14

6-Oct-05 5:14

Yes, we can use ReadBytes, then why bother to use BinaryReader!?
I like to BinaryReadar because you read primitive types.

using ReadBytes you have to write code like this:

byte[] data = f.ReadBytes(sizeof(double));
double value = BitConverter.ToDouble(data, 0);

The problem is that accroding to documentation:

==== Microsoft Documentation ====
Return Value
A byte array containing data read from the underlying stream. This might be
less than the number of bytes requested if the end of the stream is reached.
======

What happen when EOF is reached? data is null?
Also this could generate an exception to be thrown when I call BitConverter.ToDouble().

BinaryReader is bad designed. Dead | X|

Eduardo Diaz

site | english blog | spanish blog

Guffa6-Oct-05 6:12

Guffa

6-Oct-05 6:12

ediazc wrote:
What happen when EOF is reached? data is null?

No. You simply get an array that contains less bytes that you requested.

The way to detect end of stream is to examine the length of the array. If the length is shorter than the number of bytes requested, you have reached the end of the stream. The array will contain the last remaining bytes of the stream. If you already read all data up to the end, the length of the array will be zero.

You have to check the length of the array before you try to convert the bytes to a double. If there aren't bytes enough for a double, you have reached the end of the stream.

ediazc wrote:
BinaryReader is bad designed.

I don't think so. Perhaps it's not designed the way you are used to, or maybe not designed the way you try to use it. I believe it's rather well designed for it's purpose, though.

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S. Senthil Kumar5-Oct-05 19:42

S. Senthil Kumar

5-Oct-05 19:42

From your blog, your first snippet of code does work, with a few modifications.

void Open() 
{
	FileStream stream = File.Open(@"C:\myfile.txt", FileMode.Open);
	byte b;
	// ReadByte returns -1 at EOF.
	while ((b = (byte)stream.ReadByte()) != 255) 
	{
        	Console.WriteLine(b.ToString());
	}
}

Regards
Senthil
_____________________________
My Blog | My Articles | WinMacro

Guffa5-Oct-05 19:50

Guffa

5-Oct-05 19:50

Then it can't be used to read a file thas has the byte value 255 in it, as that also will be interpreted as end of file.

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S. Senthil Kumar5-Oct-05 20:38

S. Senthil Kumar

5-Oct-05 20:38

Oops. b must have been declared int and I shouldn't have casted ReadByte. This will work

void Open() 
{
	FileStream stream = File.Open(@"C:\myfile.txt", FileMode.Open);
	int x;
	// ReadByte returns -1 at EOF.
	while ((x = stream.ReadByte()) != -1) 
	{
		byte b = (byte)x;
		Console.WriteLine(b.ToString());
	}
}

Regards
Senthil
_____________________________
My Blog | My Articles | WinMacro

ediazc6-Oct-05 5:04

6-Oct-05 5:04

Send the correction to the guy who wrote the original code on MSDN[^]

Eduardo Diaz

site | english blog | spanish blog

ediazc6-Oct-05 5:01

6-Oct-05 5:01

That particular code is not mine, is taken from microsoft documentation.
The error is from the documenter, who obviusly doesn't know how to read a stream Dead | X|

.

Eduardo Diaz

site | english blog | spanish blog

WebClient and HTTPWebRequest dealing with redireciton?

Moshe B16-Apr-10 5:18

Moshe B

16-Apr-10 5:18

well.. why don't you just check if the stream position property equals to the length?
that should solve the problem.

void Open()
{
FileStream stream = File.Open(@"C:\myfile.txt", FileMode.Open);
	byte b;
	// ReadByte returns -1 at EOF.
	while (stream.Position < stream.Length) 
	{
        	(b = (byte)stream.ReadByte()) != 255
        	Console.WriteLine(b.ToString());
	}
}

It will also work if you are using a BinaryReader.

Red_Wizard_Shot_The_Food5-Oct-05 15:00

Red_Wizard_Shot_The_Food

5-Oct-05 15:00

I want my program downloads an HTML file from a site using a simple address that normaly causes my browser to redirect to a LONG complicated address showing the site im after.
But when i try to access the same page from my program using the same shortened address i download an HTML file but its just basicly a blank html file (head and body) with an error message in the body.

Rather than the page my browser redirects to.
I have tried feeding my program the LONG(actual) address and it reads the file just fine form there. But i cant depend on my program recieving the long direct address when its up and running.
So is there a way to get it to read the page it should be redirected to?

Thanks.

-- modified at 21:30 Wednesday 5th October, 2005
/EDIT: I meant to add im using request.AllowAutoRedirect=true;

Re: WebClient and HTTPWebRequest dealing with redireciton?

Red_Wizard_Shot_The_Food5-Oct-05 16:05

Red_Wizard_Shot_The_Food

5-Oct-05 16:05

Hmm it seems the redirection does work when used on other pages.... is it possible that some form of spider/bot blocking could be inplace to stop the redireciton or is it somthing as simple as me needing to learn how to enable cookies, etc?

newbee ques on structs

ter815-Oct-05 14:12

ter81

5-Oct-05 14:12

Hi,
I am doing a project using forms. I want to create a global struct common to all forms. I want to create an array of that struct and to set the values in one form and retrieve in other forms.
How do I do it. I have created the struct but each time when I create an object for the struct the values are lost.
pls help.

enjoycrack5-Oct-05 14:19

enjoycrack

5-Oct-05 14:19

hi there,

Sure everytime u create an obj for the struct, actually it's a new obj so no old values are stored in this obj.

ter81 wrote:
I want to create a global struct common to all fo

just create this in the top parent form's scope so that u can access this later in another forms. And this will be freed from memory when the top form is closed.

Hope this answers

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ter815-Oct-05 14:24

ter81

5-Oct-05 14:24

I dont have a parent-child form hierarchy, but individual form that have links to each other.
I have created the structure iinside the namespace. but I was wondering how do I create a global object for this structure.

enjoycrack6-Oct-05 10:31

enjoycrack

6-Oct-05 10:31

You can do whatever u want in ur app. But whenever ur app is still alive, the pointer to the struct should be persistent too.

U can achieve this by using static variable.

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