C# Discussion Boards - CodeProject

Re: Starting to read a file from an origin with Binaryreader

15-Jul-09 4:04

I think you have been trying to do this for a couple of days, yes?

I also think you have the wrong idea what a BinaryReader is and what BinaryReader.Read(byte[], int, int) actually does.

A BinaryReader is not intended to read a stream of binary data from a file. It is intended to read primitive types (such as int32, int64 etc) from a file. What you appear to be trying to do needs a straight FileStream or similar.

The BinaryReader.Read(byte[] buffer, int start, int length) reads length bytes into the buffer, starting to fill at buffer[start] - not reads bytes into buffer starting to fill from stream[start].

Search MSDN for BinaryReader; it is all there in English. Or Microsofts' version of English, at least.

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SimpleData15-Jul-09 4:13

Re: Starting to read a file from an origin with Binaryreader

15-Jul-09 4:13

Thank you for your answer. Yes, I've been working on this for couple of days.

I've tried using FileStream too but again got the same result.

Maybe the problem is the method for looking the location of the string in file. Any suggestions on how the find the location of string in file

OriginalGriff15-Jul-09 4:33

Re: Starting to read a file from an origin with Binaryreader

15-Jul-09 4:33

Try this:

using (FileStream fs = new FileStream(@"C:\XXTemp\Test.bin", FileMode.Open))
    {
    if (fs.CanSeek)
        {
        fs.Seek(0x53, 0);
        byte[] buffer = new byte[8];
        fs.Read(buffer, 0, 8);
        StringBuilder sb = new StringBuilder();
        foreach (byte b in buffer)
            {
            sb.Append((char) b);
            }
        MessageBox.Show(sb.ToString());
        }
    }

The StringBuilder stuff is just to display the buffer and show it works byte by byte.

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SimpleData15-Jul-09 4:44

Re: Starting to read a file from an origin with Binaryreader

15-Jul-09 4:44

I just tried your solution too, while debugging at watches it shows that fs's position is the position that I want but it doesn't work that way. It has lots of \0 when converted to string.

Luc Pattyn15-Jul-09 4:54

Luc Pattyn

15-Jul-09 4:54

so your string probably uses Unicode, meaning the ASCII character set gets represented by 16-bit numbers with their high byte equal to zero. There are many ways a string can be hidden in an EXE, ASCII and Unicode are the top two.

Smile | :)

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Re: Starting to read a file from an origin with Binaryreader

OriginalGriff15-Jul-09 4:59

Re: Starting to read a file from an origin with Binaryreader

15-Jul-09 4:59

Try it with a known file: Save this page to a temporary file, and replace the c:\XXTemp\Test.bin with that file. Then, change as shown below:

using (FileStream fs = new FileStream(@"C:\XXTemp\CodeProject Reply to Message_ Free source code and programming help.mht", FileMode.Open))
    {
    if (fs.CanSeek)
        {
        fs.Seek(0x44, 0);
        byte[] buffer = new byte[100];
        fs.Read(buffer, 0, 100);
        StringBuilder sb = new StringBuilder();
        foreach (byte b in buffer)
            {
            sb.Append((char)b);
            }
        MessageBox.Show(sb.ToString());
        }
    }

Note changes in Seek, buffer size and amount read.
When I run this, I get

Reply to Message. Free source code and programming help
Date: Wed, 15 Jul 2009 15:50:47 +0100
MIME

Open your file in Notepad (not by double clicking) and see if what you get in the MessageBox matches the file.

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SimpleData15-Jul-09 4:52

Re: Starting to read a file from an origin with Binaryreader

15-Jul-09 4:52

I write the data to the end of file with this code:

public bool AppendToBinary(string File, string strToAppend)
        {
            FileStream fs = null;
            BinaryWriter bw = null;

            try { fs = new FileStream(File, FileMode.Open, FileAccess.ReadWrite); }
            catch { throw new Exception("Dosya akışı oluşturulurken hata oluştu."); }

            try { bw = new BinaryWriter(fs); }
            catch { throw new Exception("Binary okuyucu oluşturulurken hata oluştu."); }

            try
            {
                bw.Seek(0, SeekOrigin.End);
                bw.Write(strToAppend);
            }
            catch { throw new Exception("Dosyaya yazılırken hata oluştu."); }
            finally { bw.Close(); fs.Close(); fs.Dispose(); }

            return true;
        }

I get the location of the desired string in file with this code:

public long DigBinary(string File, string strToDig)
{
    FileStream fs = null;

    try { fs = new FileStream(File, FileMode.Open, FileAccess.Read); }
    catch { throw new Exception("Dosya akışı oluşturulamadı."); }

    try
    {
        byte[] icerik = new byte[fs.Length];
        fs.Read(icerik, 0, (int)fs.Length);

        string asText = Encoding.UTF8.GetString(icerik);
        int index = asText.IndexOf(strToDig);

        if (index == -1)
            return -1;

        if (strToDig != asText.Substring(index, strToDig.Length))
            return -2;

        return index;
    }
    catch { throw new Exception("Dosya okunurken hata oluştu."); }
    finally { fs.Close(); fs.Dispose(); }
}

I try to read data from the desired location of file to the end with this method: But it doesn't work...

public string ReadBinary(string File, long origin)
        {
            FileStream fs = null;

            try { fs = new FileStream(File, FileMode.Open, FileAccess.Read); }
            catch { throw new Exception("Dosya akışı oluşturulamadı."); }
            StringBuilder sb = new StringBuilder();
            try
            {
                if (fs.CanSeek)
                {
                    fs.Seek(origin, 0);
                    byte[] buffer = new byte[fs.Length];
                    fs.Read(buffer, 0, (int)fs.Length);

                    foreach (byte b in buffer)
                    {
                        try
                        {
                            sb.Append((char)b);
                        }
                        catch { };
                    }
                    MessageBox.Show(sb.ToString());
                }

                return sb.ToString();
            }
            catch { throw new Exception("Dosya okunurken hata oluştu."); }
            finally { fs.Close(); fs.Dispose(); }
        }

OriginalGriff15-Jul-09 5:03

Re: Starting to read a file from an origin with Binaryreader

15-Jul-09 5:03

The bits I mentioned about BinaryReader working with primitives also applies to BinaryWriter.
Replace that with a fileStream, and it should work. If in doubt, look at your file content with a hex editor / viewer - I use PSPad which is freeware and available from PSPad[^] This will confirm you have the correct data written at the correct address.

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SimpleData15-Jul-09 5:08

delete rows in listView using KeyPressed event and Delete Key

15-Jul-09 5:08

I am using HexWorkshop as my hex editor and I could see the string that I wrote to the end of file but I wasn't checked that if my application find the correct location and apparently it wasn't finding the correct location so I should be working on my DigBinary method.

al3xutzu0015-Jul-09 3:14

al3xutzu00

15-Jul-09 3:14

Hi Guys,
I have been trying to implement the KeyPress event on a listView so that when i use the DELETE key, i will delete the selected rows (MultiSelect=true)

The code works fine when i use a button to call it from :

private void btnDeleteRow_Click(object sender, EventArgs e)
{
    while (listView1.SelectedIndices.Count > 0)
    {
        listView1.Items.RemoveAt(listView1.SelectedIndices[0]);
    }
}

However in MSDN documentation it is explicitly said that e.KeyChar can't be used for DELETE and several other special function keys like F1-F12 , PageUp etc...

http://msdn.microsoft.com/en-us/library/system.windows.forms.keypresseventargs.keychar.aspx[^]

How can i use the DELETE KEY to delete items in listViews?

Kind regards,
Alex Confused | :confused:

“Be the change you want to see in the world.”

Re: delete rows in listView using KeyPressed event and Delete Key

Christian Graus15-Jul-09 3:14

Christian Graus

15-Jul-09 3:14

Perhaps the key up or key down event gets more eventargs ?

Christian Graus

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Read my blog to find out how I've worked around bugs in Microsoft tools and frameworks.

Re: delete rows in listView using KeyPressed event and Delete Key

al3xutzu0015-Jul-09 3:20

al3xutzu00

15-Jul-09 3:20

Thank you Christian, it works perfect with KeyDown and e.KeyCode.
Here is the implementation :

private void listView1_KeyDown(object sender, KeyEventArgs e)
{
    if (listView1.SelectedItems.Count != 0 && e.KeyCode == Keys.Delete)
    {

        while (listView1.SelectedIndices.Count > 0)
        {
            listView1.Items.RemoveAt(listView1.SelectedIndices[0]);
        }
    }
}

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Re: delete rows in listView using KeyPressed event and Delete Key

Christian Graus15-Jul-09 3:45

Christian Graus

15-Jul-09 3:45

I don't know why keypressed doesn't get the same eventargs, but I had a feeling that was the case. There may be a systemkeypress event or similar, but I find keydown or keyup easier to deal with.

Christian Graus

Driven to the arms of OSX by Vista.

Read my blog to find out how I've worked around bugs in Microsoft tools and frameworks.

Re: delete rows in listView using KeyPressed event and Delete Key

Nagy Vilmos15-Jul-09 3:52

Nagy Vilmos

15-Jul-09 3:52

For some reason[1], the normal control and navigation keys[2] are not exposed except in key down/up events. It's been this way as long as I can remember[3] and I can't see it changing soon. That would be sensible[4].

[1] I think Bill was drunk that day.
[2] The ones you are most likely to want to override.
[3] Ten years even after lunch.
[4] Should you actually want to write code.

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Re: delete rows in listView using KeyPressed event and Delete Key

Nagy Vilmos15-Jul-09 3:59

Nagy Vilmos

15-Jul-09 3:59

You should take care with this, it's not a good idea to make the change on the key down. I would recommend setting a flag when the button is pressed and checking for the flag when it's released, that is closer to the key pess event.

Panic, Chaos, Destruction.
My work here is done.

Re: delete rows in listView using KeyPressed event and Delete Key

MatheusMK35-Aug-09 10:40

MatheusMK3

5-Aug-09 10:40

I had the same problem and i used this code:

private void listView1_KeyDown(object sender, KeyEventArgs e)
{
    if (e.KeyCode == Keys.Delete)
    {
        listView1.Items.RemoveAt(listView1.SelectedIndices[0]);
    }
}

I hope this help you...

public void showSignature(object sender, MyForumSignatureEventArgs e)
{
signatureLabel.Text = e.Signature("MatheusMK3", "codeproject.com", "Forum");
}

Recreate OracleDataReader?

Mark McArthey15-Jul-09 3:10

Mark McArthey

15-Jul-09 3:10

I'm writing an Active Directory class in which I'd like to recreate the implementation of the OracleDataReader. For those of you not familiar, you can create an object in the typical fashion:

OracleDataReader reader = cmd.ExecuteReader(blah, blah);

The implementation is similar to the following:

while (reader.Read())
{
   Add(reader["name"].ToString());
}

What's important to note is the fact that the Read() method returns a boolean. My ExecuteReader() method (I named mine something else) generates a DataView. I can envision the equivalent Read() method stepping through the DataView and returning this boolean value whether or not more records exist.

The item I'm stuck on is the implementation of access an object like a HashTable. I'm relatively new to the OOP world but I haven't seen this sort of access method before and am not sure how to implement it. Is this somehow overriding the array method?

I'd appreciate any tips on how to get started!

Thanks!

Re: Recreate OracleDataReader?

Ennis Ray Lynch, Jr.15-Jul-09 3:24

Ennis Ray Lynch, Jr.

15-Jul-09 3:24

If you are trying to generate your own DataReader it must implement and adhere to System.Data.IDataReader, otherwise you are just creating a different entity with a confusing name. I would rethink your approach and make sure you are not reinventing the wheel.

The indexor on the datareader (reader["name"] in your code) calls dr.GetValue(dr.GetOrdinal("name")) and is really just a handy set of convenience methods. Also, note, that the type returned from reader["name"] is an object. ToString is only used to provide a string representation of an object not to cast objects. You should use the appropriate cast instead, ie: (string)reader["name"].

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"Sir I exist!"
"However," replied the universe,
"The fact has not created in me
A sense of obligation."
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Enum outlook folder

john563215-Jul-09 2:59

15-Jul-09 2:59

Hi,

I am getting problem to enum outlook folder using PIA.
I have namespace object, but how to enumerate outlook folder, Its confusing.

Microsoft.Office.Interop.Outlook.MAPIFolder Fldr=NspObj.Folders.GetFirst();

I am not able to find any interface to traverse the folder of outlook.
Please guide me.

benjymous15-Jul-09 3:22

benjymous

15-Jul-09 3:22

Here's an example that recurses your outlook folder structure, looking for a named folder

using Microsoft.Office.Interop.Outlook;

...

        Microsoft.Office.Interop.Outlook.Application outlook = new Microsoft.Office.Interop.Outlook.Application();



        private Folder FindFolderRecursive(Folders start, string name)
        {
            foreach (Folder folder in start)
            {               
                if (folder.Name == name)
                {
                    return folder;
                }
                Folder found = FindFolderRecursive(folder.Folders, name);
                if (found != null)
                {
                    return found;
                }
            }
            return null;

        }

        private void Form1_Shown(object sender, EventArgs e)
        {
            Folder stuff = FindFolderRecursive(outlook.Session.Folders, "Stuff")

            foreach(Mailitem item in stuff.Items)
            {
               // do stuff to your mail items!
            }

        }

Help me! I'm turning into a grapefruit!
Buzzwords!

john563215-Jul-09 21:29

15-Jul-09 21:29

Thank you,

Please give me any link that fetch the email from a folder.
Or tell me how to do?

benjymous15-Jul-09 22:25

benjymous

15-Jul-09 22:25

Erm - that's exactly what the snippet I posted does - it searches for a named folder then loops through all the mails in it.

Help me! I'm turning into a grapefruit!
Buzzwords!

john563215-Jul-09 22:40

15-Jul-09 22:40

ya thank you

john563215-Jul-09 23:05