Visual Basic

16-Jul-07 2:03

That's because the code is written for strings. I tested it using drag and drop of multiple files from Explorer.

You'll have to modify your code to put the appropriate item types into the Data object and pull those same item types out of the Data object. If you're posting and array of Object items to the drag, you have to pull the same array of Object item types off, not an array of Strings.

Post the code you're using to populate the drag.

A guide to posting questions on CodeProject[^]

Dave Kreskowiak
Microsoft MVP
Visual Developer - Visual Basic
2006, 2007

Here is the code...

sudhakar7916-Jul-07 2:54

sudhakar79

16-Jul-07 2:54

Many many thanks for your interest.
Here is the code where I am passing a string to dodragdrop() function.Please make the needfull changes to this code.

Private Sub ListBox1_MouseDown(ByVal sender As Object, ByVal e As System.Windows.Forms.MouseEventArgs) Handles ListBox1.MouseDown

If ListBox1.Items.Count = 0 Then
Return
End If

Dim lsstring As String = ListBox1.Items(ListBox1.IndexFromPoint(e.X, e.Y)).ToString()

Dim lodde1 As DragDropEffects =DoDragDrop(lsstring,DragDropEffects.All)
If lodde1 = DragDropEffects.All Then
ListBox1.Items.RemoveAt(ListBox1.IndexFromPoint(e.X, e.Y))
End If
End Sub

/************** here is the entire code of sample project************///

Public Class Form1

Private Sub ListBox1_DragDrop(ByVal sender As Object, ByVal e As System.Windows.Forms.DragEventArgs) Handles ListBox1.DragDrop
If e.Data.GetDataPresent(DataFormats.StringFormat) Then
Dim Lsstr1 As String = DirectCast(e.Data.GetData(DataFormats.StringFormat), String)
ListBox1.Items.Add(Lsstr1)
End If
End Sub

Private Sub ListBox1_DragOver(ByVal sender As Object, ByVal e As System.Windows.Forms.DragEventArgs) Handles ListBox1.DragOver
e.Effect = DragDropEffects.All
End Sub

Private Sub ListBox1_MouseDown(ByVal sender As Object, ByVal e As System.Windows.Forms.MouseEventArgs) Handles ListBox1.MouseDown
If ListBox1.Items.Count = 0 Then
Return
End If

Dim lsstring As String = ListBox1.Items(ListBox1.IndexFromPoint(e.X, e.Y)).ToString()
Dim lodde1 As DragDropEffects = DoDragDrop(lsstring, DragDropEffects.All)

If lodde1 = DragDropEffects.All Then
ListBox1.Items.RemoveAt(ListBox1.IndexFromPoint(e.X, e.Y))
End If
End Sub

Private Sub ListBox2_DragDrop(ByVal sender As Object, ByVal e As System.Windows.Forms.DragEventArgs) Handles ListBox2.DragDrop
If e.Data.GetDataPresent(DataFormats.StringFormat) Then
Dim Lsstr1 As String = DirectCast(e.Data.GetData(DataFormats.StringFormat), String)
ListBox2.Items.Add(Lsstr1)
End If
End Sub

Private Sub ListBox2_DragOver(ByVal sender As Object, ByVal e As System.Windows.Forms.DragEventArgs) Handles ListBox2.DragOver
e.Effect = DragDropEffects.All
End Sub

Private Sub ListBox2_MouseDown(ByVal sender As Object, ByVal e As System.Windows.Forms.MouseEventArgs) Handles ListBox2.MouseDown
If ListBox2.Items.Count = 0 Then
Return
End If
Dim ls As String = ListBox2.Items(ListBox2.IndexFromPoint(e.X, e.Y)).ToString()
Dim lodde1 As DragDropEffects = DoDragDrop(ls, DragDropEffects.All)
If lodde1 = DragDropEffects.All Then
ListBox2.Items.RemoveAt(ListBox2.IndexFromPoint(e.X, e.Y))
End If
End Sub
End Class

Thanks and Regards,
sudhakar venati,
Mob: 0 984 55 989 71.

Re: Here is the code...

Dave Kreskowiak16-Jul-07 13:25

what is the problem with this code

16-Jul-07 13:25

Ummm...Your're not populating the DragDrop with the strings at all. You're just removing the items from the source list box! There's nothing in the Drop because you didn't put anything into it!

You have to start a Drag and Drop operation by populating the data being transerfered with the ListBox's DoDragDrop[^] method.

A guide to posting questions on CodeProject[^]

Dave Kreskowiak
Microsoft MVP
Visual Developer - Visual Basic
2006, 2007

chiyankrishna12-Jul-07 23:32

chiyankrishna

12-Jul-07 23:32

Dim str1 As String
str1 = " "
Dim i As Integer
i = 0
Dim intag As Boolean
intag = False
Dim thetag As String
thetag = " "
Dim htmlinput As String
htmlinput = TextBox1.Text
Dim tempchar As String
Const a As String = "ControlChars.Tab"
For i = 0 To htmlinput.Length() - 1

tempchar = htmlinput.Chars(i)
If (tempchar.Equals("<")) Then
intag = True
thetag = ""
tempchar = ""
ElseIf (tempchar.Equals(">")) Then

intag = False
tempchar = ""
ElseIf (tempchar.Equals(" ")) Then
tempchar = ""
End If
If (intag) Then
thetag += tempchar
ElseIf (thetag.Equals("td")) Then
str1 += tempchar + " "
thetag = ""
ElseIf (thetag.Equals("tr")) Then
str1 += tempchar + " "
thetag = ""
ElseIf (thetag.Equals("\n")) Then
str1 += tempchar
thetag = ""
Else
str1 += tempchar
End If
Next
TextBox2.Text = str1

i have a file txt file with following text

row1	col1
row2	col2

now i want to display the txt file code in another textbox as this is displayed in a html file.

my code at the top has a certain mistake. which i am not able to rectify.

could any one help

there is no such thing as good or bad.

Guffa12-Jul-07 23:42

12-Jul-07 23:42

Why do you think that there is a problem with the code?

What is it supposed to do?

---
single minded; short sighted; long gone;

Vasudevan Deepak Kumar13-Jul-07 0:05

Vasudevan Deepak Kumar

13-Jul-07 0:05

Missing Indentation. Big Grin | :-D

Vasudevan Deepak Kumar
Personal Homepage
Tech Gossips

chiyankrishna13-Jul-07 0:31

chiyankrishna

13-Jul-07 0:31

my code is not helping me to display as it would be displayed in a html page. but it is displaying as it is from the text file

ie i want my code to display the text file as

row one col one

row two col two

but my code is displaying like this

row one
col one

row two
col two

there is no such thing as good or bad.

Dave Kreskowiak13-Jul-07 2:53

13-Jul-07 2:53

"\n" doesn't have any meaning in VB.NET. Replace it with Environment.NewLine and it might work, or ControlChars.Cr, or ControlChars.Lf, or ControlChars.CrLf, just to make sure you get all the possible carriage returns and line feeds.

A guide to posting questions on CodeProject[^]

Dave Kreskowiak
Microsoft MVP
Visual Developer - Visual Basic
2006, 2007

Guffa13-Jul-07 3:18

13-Jul-07 3:18

Dave is on the right track, however Environment.NewLine or ControlChars.CrLf won't work as you are looking at a single character at a time.

A line break consists of a carriage return and a line feed. You have to compare against both ControlChars.Cr and ControlChars.Lf to handle both of the characters.

---
single minded; short sighted; long gone;

Dave Kreskowiak13-Jul-07 3:31

13-Jul-07 3:31

Whoops! I haven't had my Coke yet this morning. Big Grin | :-D

A guide to posting questions on CodeProject[^]

Dave Kreskowiak
Microsoft MVP
Visual Developer - Visual Basic
2006, 2007

Why can't i catch parameter

Paul Conrad13-Jul-07 4:32

Paul Conrad

13-Jul-07 4:32

Putting comments in your code would be helpful. Helps give some idea of what is going on Big Grin | :-D

"Any sort of work in VB6 is bound to provide several WTF moments." - Christian Graus

boyindie12-Jul-07 23:10

12-Jul-07 23:10

Hi
I have the following function for returning a user specific salt using a stored procedure in mySQL

But my code doesn't seem to be returning a value from my OUTput parameter, can anyone see a problem

Cheers

code is

Sub getSalt(ByVal sender As Object, ByVal e As EventArgs)
'Create connection string to pass database, string holds login information to mySQL,
Dim connectionString As String
connectionString = "Server=localhost; uid=;database=ftp1;"

'Builds .net mysql connection and passes connection string into method
Dim connection As New MySqlConnection(connectionString)
'Create mySql command string for passing query or SPROC(Stored Procedure)
Dim cmdString As New MySqlCommand
'Set Command to equal mySql connection,t so can pass SQL query
cmdString.Connection = connection

'Set command string to equal SPROC
cmdString.CommandText = "sp_getSalt"
'ONLY PLACE THIS IF SPROC, sets the command to a SPROC
cmdString.CommandType = CommandType.StoredProcedure
Dim literr As New LiteralControl

Dim param As MySqlParameter
Try

param = cmdString.Parameters.Add("?p_salt", MySqlDbType.VarChar)
cmdString.Parameters("?p_salt").Direction = ParameterDirection.Output

Dim salt As String = cmdString.Parameters("?p_salt").Value
sendData(sender, e, salt)

Catch ex As Exception
literr.Text = ex.Message
MsgBox(ex.Message)

End Try

Procedure is
CREATE DEFINER=`jshort`@`localhost` PROCEDURE `sp_getSalt`(IN p_userName VARCHAR(20), OUT p_salt varchar(500))
BEGIN
SELECT salt INTO p_salt FROM Users WHERE UserName = p_UserName;
END

Guffa12-Jul-07 23:40

12-Jul-07 23:40

Perhaps if you tried to actually execute the procedure... Wink | ;)

---
single minded; short sighted; long gone;

boyindie12-Jul-07 23:47

12-Jul-07 23:47

i know i jus realised how retarded i was, it is also helpful if I passed the username into it as well...

But it still doesn't work Frown | :(

Correct me if my reasonin is wrong here

when i create a user i provide them with a random salt

Then when i encrpyt the password, i also add the salt into that encryption, so providing a unique password (yes/no?)

When i log in

I get the application to grab the users salt based on the username entered
I then need to do the same process as before of taking the username entered and using the salt i retrieved, and encrpyting them again

and this should *in theory* be the same password as stored

but it doesn't seem to work like this, so i am takin my reasoning is fatally flawed somewhere

Dave Kreskowiak13-Jul-07 2:45

13-Jul-07 2:45

No, that's correct. The problem could be in how you stored the salt. What you created your salt and added it to the password, are you getting back the EXACT same salt out of the database just before you add it to the entered password attempt?

A guide to posting questions on CodeProject[^]

Dave Kreskowiak
Microsoft MVP
Visual Developer - Visual Basic
2006, 2007

boyindie13-Jul-07 2:56

13-Jul-07 2:56

I have checked that by gettin it display the value in messagebox's and it returns the same salt value which is commited to the database each time

boyindie13-Jul-07 3:05

13-Jul-07 3:05

this is the code that i use to create the salt

Dim shaHash As New System.Security.Cryptography.SHA384Managed()

Dim hashedBytes As Byte()

Dim encoder As New UTF8Encoding()

Dim data() As Byte
data = New Byte(6) {}
Dim rng As New RNGCryptoServiceProvider
rng.GetBytes(data)

Dim PSalt As String = encoder.GetString(data)
MsgBox(PSalt)

i then do the following to encrypt my password and i just pass the psalt variable into my salt field in database

hashedBytes = shaHash.ComputeHash(encoder.GetBytes(txtPassword.Text & PSalt))
Dim PWhash As String = encoder.GetString(hashedBytes)

param = cmdString.Parameters.Add("?p_Password", MySqlDbType.VarChar)
param.Direction = ParameterDirection.Input
param.Value = PWhash
MsgBox(PWhash)

to log in I have the following function which gets my salt

cmdStringS.CommandText = "sp_getSalt"
cmdStringS.CommandType = CommandType.StoredProcedure

Dim literr As New LiteralControl

Dim param As MySqlParameter
Try

param = cmdStringS.Parameters.Add("?p_username", MySqlDbType.VarChar)
param.Direction = ParameterDirection.Input
param.Value = txtUserName.Text

param = cmdStringS.Parameters.Add("?p_salt", MySqlDbType.VarChar)
cmdStringS.Parameters("?p_salt").Direction = ParameterDirection.Output

connection.Open()
cmdStringS.ExecuteScalar()
connection.Close()

Catch ex As Exception
literr.Text = ex.Message
MsgBox(ex.Message)

End Try
Dim salted As String = cmdStringS.Parameters("?p_salt").Value
sendData(sender, e, cmdStringS, salted)

I then pass salted variable to my data submit method, where i do the followin wit the password and hash

hashedBytes = shaHash.ComputeHash(encoder.GetBytes(txtPassword.Text & salted))
Dim PWhash As String = encoder.GetString(hashedBytes)
param = cmdString.Parameters.Add("?p_Password", MySqlDbType.VarChar)
param.Direction = ParameterDirection.Input
param.Value = PWhash

Dave Kreskowiak13-Jul-07 5:51

13-Jul-07 5:51

Hmmm...I can't really see anything wrong with it. I've done similar stuff in the past, but instead of using UTF8 encoding to convert the salt to a string, I converted it to a Base64 string and added that you the password.

I've always generated the salt in a seperate function, generated the salted password hash in another...

Private Function GenerateSalt(ByVal size As Integer) As String
    ' The drop dead minumum useful salt size is 5 bytes, and
    ' a max of 12 would generate a string of 8 to 20 Base64 characters.
    size = Math.Min(Math.Max(5, size), 12)
 
    Dim rng As New RNGCryptoServiceProvider()
    Dim buffer(size) As Byte
    rng.GetBytes(buffer)
 
    Return Convert.ToBase64String(buffer)
End Function
 
Private Function GenerateSaltedPasswordHash(ByVal password As String, ByVal salt As String) As String
    ' This section is GREATLY simplified.  I normally do something MUCH more
    ' wicked to combine the password and salt, and hash it.  Of course, I'm not saying what...
    Dim saltedPassword As String = password & salt
    Dim SHA As New SHA512Managed
    Dim buffer() As Byte = Encoding.UTF8.GetBytes(saltedPassword)
 
    Return Convert.ToBase64String(SHA.ComputeHash(buffer))
End Function

Why do I use Base64 so much?? Easy. The return values are suitable for storage on/in ANY medium. XML files, any database, any file, ...

This version of the function would generate a password hash string about 80 to 100 characters long. Your milage may vary. This length of password may or may NOT be acceptable to you. Consider the situation where you may have 60,000,000 users. That's a password column containing 6GB of data, not counting the salt storage, or any other user data.

A guide to posting questions on CodeProject[^]

Dave Kreskowiak
Microsoft MVP
Visual Developer - Visual Basic
2006, 2007

Guffa13-Jul-07 6:03

13-Jul-07 6:03

boyindie wrote:
Dim data() As Byte
data = New Byte(6) {}
Dim rng As New RNGCryptoServiceProvider
rng.GetBytes(data)

Dim PSalt As String = encoder.GetString(data)

That's not a good way to create a random string. The random bytes that you create might not correspond to actual characters in that encoding. Also, as some characters are encoded into more than one byte, you might create a byte patten that ends in a half character.

Just start with a non-random string like "asdf" until you have got the rest of the code working.

param = cmdString.Parameters.Add("?p_Password", MySqlDbType.VarChar)
param.Direction = ParameterDirection.Input
param.Value = PWhash

Unless you have set up your database to use unicode, it will not be able to store any unicode characters.

There is no code to actually store anything in the database. Is it missing, or did you just omit it?

cmdStringS.ExecuteScalar()

Why are you using ExecuteScalar, when you don't read anything from the result? Use ExecuteNonQuery instead.

---
single minded; short sighted; long gone;

boyindie16-Jul-07 4:33

16-Jul-07 4:33

There is actually code for commiting to the database, I just missed it out

'encrypt(password)
hashedBytes = shaHash.ComputeHash(encoder.GetBytes(txtPassword.Text & PSalt))
Dim PWhash As String = encoder.GetString(hashedBytes)
param = cmdString.Parameters.Add("?p_Password", MySqlDbType.VarChar)
param.Direction = ParameterDirection.Input
param.Value = PWhash

I have the thing working when i don't use the salt, but as soon as I add the salt it will never match the value stored in the table

Guffa16-Jul-07 12:15

16-Jul-07 12:15

boyindie wrote:
hashedBytes = shaHash.ComputeHash(encoder.GetBytes(txtPassword.Text & PSalt))
Dim PWhash As String = encoder.GetString(hashedBytes)

You can't just take any byte sequence and decode it as UTF-8. Only a byte sequence that is created by encoding a string as UTF-8 can be safely decoded that way.

If you want to create a string representation of a byte sequence, use something like base64.

boyindie wrote:
I have the thing working when i don't use the salt

Then you were just lucky to get byte sequences that happened to be possible to decode using the UTF-8 encoding without losing data.

---
single minded; short sighted; long gone;

boyindie16-Jul-07 12:18

16-Jul-07 12:18

I have now sorted this issue out I have the login now workin along with the salt Big Grin | :-D

I am usin the method suggested by dave further back in the saga of this string

Just need to learn how to get sessions workin or a cookie, and i am sorted

My own equalizer

bala_kathir12-Jul-07 21:20

bala_kathir

12-Jul-07 21:20

Hi guys i want to built my own equalizer(sound control) using vb.net.so can anyone give me the codings to develop it.Thanks in advance..

Bala

Re: My own equalizer

Dave Kreskowiak13-Jul-07 2:41