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Hi Guys,
I have a quick and hopefully not to difficult question to the commmunity. I have a program that reads an excel spreadsheet, adds the data to a datatable inside a dataset and displays it in a wpf datagrid using databinding.
Here is the code for it, it works fine just like I imagined it  . I also have a funciton that returns all the sheets in a excel spreadsheet.
Private Sub Button_Click_1(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
Dim m_sConn1 As String = "Provider=Microsoft.ACE.OLEDB.12.0;" & _
"Data Source=C:\Temp\Test.xlsx;" & _
"Extended Properties=""Excel 12.0 Xml;HDR=No;IMEX=1"""
Dim conn1 As New System.Data.OleDb.OleDbConnection(m_sConn1)
conn1.Open()
Dim da As OleDbDataAdapter
Dim ds As New System.Data.DataSet
Dim test As String
test = "[Sheet1b$]"
Dim teststring As String
teststring = "Select * FROM" & test & """"
da = New OleDbDataAdapter(teststring, conn1)
da.Fill(ds, "TestTable")
da.Dispose()
Dim bindingSource As New BindingSource(ds, "TestTable")
excelDataGrid.ItemsSource = bindingSource
conn1.Close()
End Sub
Private Sub getList_Click(sender As Object, e As RoutedEventArgs) Handles getList.Click
Dim m_sConn1 As String = "Provider=Microsoft.ACE.OLEDB.12.0;" & _
"Data Source=C:\Temp\Test.xlsx;" & _
"Extended Properties=""Excel 12.0 Xml;HDR=No;IMEX=1"""
Dim conn1 As New System.Data.OleDb.OleDbConnection(m_sConn1)
conn1.Open()
Dim test As New System.Data.DataTable
test = conn1.GetOleDbSchemaTable(OleDbSchemaGuid.Tables, Nothing)
If test Is Nothing OrElse test.Rows.Count < 1 Then
Throw New Exception("Error: Could not determine the name of the first worksheet.")
End If
Dim firstSheetName As String
Dim i As Integer
For i = 0 To test.Rows.Count - 1
firstSheetName = test.Rows(i)("TABLE_NAME").ToString()
List1.Items.Add(firstSheetName)
Next
End Sub
My question now is this. I'd like to have the program iterate through the first column of the data and match the entries with known parameters. For example. the user has a cell that says EmpID, I want the program to recognize it and change it to Employee ID. Upon recognizing all of these, I want the program to display the data with the new cell values in a different datagrid.
My thought was this: Load data from excel -> fill datatable in dataset -> bind data to datagrid for visual confirmation that data was imprted correctly -> in different sub obtain the databinding for the wpf datagrid and fill a new datatable in a new dataset -> go through the recognizing function -> and spit out the data in a new datatable
I tried looking for a way to do it but am having trouble with getting the data. All I could find online was how to get data into a datagrid and not the other way around.
initially I thought it would be as simple as
Dim TestDataTabe As System.Data.DataTable
TestDataTabe = DirectCast(excelDataGrid.ItemsSource, System.Data.DataView).ToTable
but that didn't seem to work and it told me an error: Unable to cast object of type 'System.Windows.Forms.BindingSource' to type 'System.Data.DataView'.
so now I am stuck and can't find anything on Dr. Google about getting the datatable that is used to fill the datagrid. Would someone be able to help me out, it would be greatly appreciated. Is it possible to have a databinding for a datatable? As in Datatable.bindingsource = datagrid.bindingsource?
Update:
so it seems that I always sorta solve my problems when I post on a forum lol. So here is what I did and hope that you guys can give me input to see if it is a viable way to do this sort of thing.
Instead of creating a dataset I created a datatable and instead of using binding source I used datagrid.itemssource = datatable.defaultview
then i direct casted it totable here is the code
Private Sub Button_Click_1(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
Dim m_sConn1 As String = "Provider=Microsoft.ACE.OLEDB.12.0;" & _
"Data Source=C:\Temp\Test.xlsx;" & _
"Extended Properties=""Excel 12.0 Xml;HDR=No;IMEX=1"""
Dim conn1 As New System.Data.OleDb.OleDbConnection(m_sConn1)
conn1.Open()
Dim da As OleDbDataAdapter
Dim ds As New System.Data.DataTable
Dim test As String
test = "[Sheet1b$]"
Dim teststring As String
teststring = "Select * FROM" & test & """"
da = New OleDbDataAdapter(teststring, conn1)
da.Fill(ds)
da.Dispose()
excelDataGrid.ItemsSource = ds.DefaultView
conn1.Close()
End Sub
Private Sub Button_Click_2(sender As Object, e As RoutedEventArgs)
Dim TestDataTabe As System.Data.DataTable
TestDataTabe = DirectCast(excelDataGrid.ItemsSource, System.Data.DataView).ToTable
End Sub
Now I got more questions lol How would you set the itemssource of the datagrid to a table inside a dataset? Sorry for the long post but maybe it helps someone out.
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I want to convert VB6 project to VB.Net. I an facing some problems.
I have separated huge VB6 project into separate dlls based in functionality. All business logic is in dll and UI is in exe program.
Out of all dlls, one dll only caontains UDT(User Defined Types) and it's used by Main exe program and all other dlls. Now I want to Convert all dlls and main program in VB.Net STEP BY STEP. I have decided to convert all dlls first and then main program.
If I convert other dll to .Net I ran into Case1 error
If I convert UDT dll to .Net using Structure, I got case 2 error
I am giving my dummy code for both the cases and problem/error description below.
Case 1:
UDT dll is in VB6 -->Name: Dll_EmployeeType
Type Employee_Properties
Employee_Id as integer
Employee_Name as String
Employee_Address as string
End Type
.Net Dll -->Name: Dll_Employee_Methods --> this refers vb6 dll Dll_EmployeeType
Class Cls_Employee
Function Display_NoOf_Employees(byval arr_employee as Dll_EmployeeType. Employee_Properties)
Msgbox ubound(arr_employee)
End Class
VB6 Exe: main program --> this refers vb6 dll Dll_EmployeeType and Dll_Employee_Methods
This program has form and button on it.
On Button_Click
Dim arr_employee() as Dll_EmployeeType. Employee_Properties
Redim arr_employee(1 to 2)
arr_employee(1). Employee_Id = 1
arr_employee(1). Employee_Name = ?name1?
arr_employee(1). Employee_Address = ?address1?
arr_employee(2). Employee_Id = 2
arr_employee(2). Employee_Name = ?name2?
arr_employee(2). Employee_Address = ?address2?
dim obj as new Dll_Employee_Methods. Cls_Employee
call obj. Display_NoOf_Employees(arr_employee)
error occurs at above line is ?Class does not support an automation or does not support expected interface?
Note: If .Net dll code is in normal class ? no intellicense is displayed in main program
If .Net dll code is in COM class ? intellicense is displayed in main program
But the error is same as above
Case 2:
Vb6 UDT dll is converted to .Net having structure
?Build tlb using COM checkbox as checked
?Add reference of it to Main exe program
?Run program
Throws an error ?Variable uses an automation type not supported in Visual basic? at first line(dim arr_employre() as?..)
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dim obj as new Dll_Employee_Methods. Cls_Employee
This refers to another class or dll which would need to be converted as well.
Else you need to use this dll as unmanaged code in your program.
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Please any one help me. How to send a mail from application (VB Coding) to E-mail such as Gmail, yahoo.
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Hello everyone. I'm writing an application to use a smart card to fill a process.info username and password. I get the credentials using CredUIPromptForWindowsCredentials and then pass (username,password,domain stringbuilder variables) to CredUnPackAuthenticationBuffer to get a networkcredential username, securepassword and domain. If I use my AD credentials, it works just fine. When I step through the code, I can see the username the is acquired from the smartcard is encrypted possibly??? I'm not really sure how to take the username that the CredUnPackAuthenticationBuffer gives me to use as the username in my process.info. When I run the code now using my smart card, i get an exception "A specified logon session does not exist. It may already have been terminated." How do I get use the username I get from the smart card in my process.info username? I hope this wasn't too confusing because I've been trying to figure this out for a week now... 
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Howdie.
I am researching how to use the Unicode version of FindFirstFileEx() in vb.Net and am having a heck of a time getting this to work. I had downloaded an example and it used the standard version, FindFirstFile(). I then modified the code to work with FindFirstFileEx(), instead, and got that to work, too, but only for ANSI characters (Alias "FindFirstFileExA"). But when I attempted to use the Unicode version (Alias "FindFirstFileExW"), it fails miserably. The best I have been able to do is get a non-zero return value from the function (which means it found the folder), but all the returned WFD structure contains are null strings for the folder name and alternate folder name.
I have googled the problem (MSDN is of no help in this regard) and did find one reference on how to alter the function parameters to provide pointers instead of a string and the WFD structure, themselves.
At any rate, here is my code for just the top half that looks for folders. The bottom half deals with searching for files, but it is just a repeat of this example, essentially. If I can get this top half to work with your help, I can certainly get the bottom half to work.
I would have liked to attach a zip containing the project and the test folder I used, but it does not look like attachments are possible, here.
Thanks for any help!
Option Strict Off
Option Explicit On
Imports VB = Microsoft.VisualBasic
Imports System.Runtime.InteropServices
Friend Class Form1
Inherits System.Windows.Forms.Form
Private Declare Function FindFirstFileExW Lib "kernel32.dll" Alias "FindFirstFileExW" (ByVal lpFileName_IntPtr As IntPtr, ByVal fInfoLevelId As FINDEX_INFO_LEVELS, ByRef lpFindFileData_IntPtr As IntPtr, ByVal fSearchOp As FINDEX_SEARCH_OPS, ByRef lpSearchFilter As Int32, ByVal dwAdditionalFlags As Integer) As Long
Private Declare Function FindNextFileW Lib "kernel32" Alias "FindNextFileW" (ByVal hFindFile As Long, ByRef lpFindFileData As WIN32_FIND_DATA) As Integer
Private Declare Function GetFileAttributesW Lib "kernel32" Alias "GetFileAttributesW" (ByVal lpFileName As String) As Integer
Private Declare Function FindClose Lib "kernel32" (ByVal hFindFile As Long) As Integer
Private Declare Function GetLastError Lib "kernel32" Alias "GetLastError" () As Integer
Const MAX_PATH As UInt16 = 260
Const MAXDWORD As UInt64 = 4294967295
Const INVALID_HANDLE_VALUE As Int16 = -1
Const FILE_ATTRIBUTE_ARCHIVE As UInt16 = &H20
Const FILE_ATTRIBUTE_DIRECTORY As UInt16 = &H10
Const FILE_ATTRIBUTE_HIDDEN As UInt16 = &H2
Const FILE_ATTRIBUTE_NORMAL As UInt16 = &H80
Const FILE_ATTRIBUTE_READONLY As UInt16 = &H1
Const FILE_ATTRIBUTE_SYSTEM As UInt16 = &H4
Const FILE_ATTRIBUTE_TEMPORARY As UInt16 = &H100
Public Enum FINDEX_INFO_LEVELS
FindExInfoStandard = 0
FindExInfoBasic = 1
FindExInfoMaxInfoLevel = 2
End Enum
Enum FINDEX_SEARCH_OPS
FindExSearchNameMatch = 0
FindExSearchLimitToDirectories = 1
FindExSearchLimitToDevices = 2
End Enum
Private Structure FILETIME
Dim dwLowDateTime As UInt32
Dim dwHighDateTime As UInt32
End Structure
Private Structure WIN32_FIND_DATA
Dim dwFileAttributes As UInt32
Dim ftCreationTime As FILETIME
Dim ftLastAccessTime As FILETIME
Dim ftLastWriteTime As FILETIME
Dim nFileSizeHigh As UInt32
Dim nFileSizeLow As UInt32
Dim dwReserved0 As UInt32
Dim dwReserved1 As UInt32
<VBFixedString(MAX_PATH), MarshalAs(UnmanagedType.ByValTStr, SizeConst:=MAX_PATH)> Public cFileName As String
<VBFixedString(14), MarshalAs(UnmanagedType.ByValTStr, SizeConst:=14)> Public cAlternate As String
End Structure
Function StripNulls(ByRef OriginalStr As String) As String
If (InStr(OriginalStr, Chr(0)) > 0) Then
OriginalStr = VB.Left(OriginalStr, InStr(OriginalStr, Chr(0)) - 1)
End If
StripNulls = OriginalStr
End Function
Function FindFilesAPI(ByRef path As String, ByRef SearchStr As String, ByRef FileCount As Integer, ByRef DirCount As Integer) As Long
Dim FileName As String
Dim DirName As String
Dim dirNames() As String
Dim nDir As Integer = 0
Dim i As Long
Dim hSearchEx As Long
Dim WFD As WIN32_FIND_DATA = Nothing
Static Cont As Boolean
FindFilesAPI = 0
If VB.Right(path, 1) = "\" Then path = VB.Left(path, Len(path) - 1)
nDir = 0
ReDim dirNames(nDir)
Cont = True
Dim fInfoLevelId As FINDEX_INFO_LEVELS = 0
Dim lpFindFileData As WIN32_FIND_DATA = Nothing
Dim fSearchOp As FINDEX_SEARCH_OPS = 0
Dim lpSearchFilter As Int32 = Nothing
Dim dwAdditionalFlags As Integer = 0
Dim lpFileName_str As String = "\\?\UNC\" & path & "\*"
Dim lpFileName_IntPtr As IntPtr = Marshal.StringToHGlobalAuto(lpFileName_str)
Dim lpFindFileData_Original As WIN32_FIND_DATA = Nothing
Dim lpFindFileData_IntPtr As IntPtr = Marshal.AllocHGlobal(Marshal.SizeOf(lpFindFileData_Original))
Try
Marshal.StructureToPtr(lpFindFileData_Original, lpFindFileData_IntPtr, False)
hSearchEx = FindFirstFileExW(lpFileName_IntPtr, fInfoLevelId, lpFindFileData_IntPtr, fSearchOp, lpSearchFilter, dwAdditionalFlags)
WFD = CType(Marshal.PtrToStructure(lpFindFileData_IntPtr, GetType(WIN32_FIND_DATA)), WIN32_FIND_DATA)
Finally
Marshal.FreeHGlobal(lpFileName_IntPtr)
Marshal.FreeHGlobal(lpFindFileData_IntPtr)
End Try
If hSearchEx <> INVALID_HANDLE_VALUE Then
Do While Cont
System.Windows.Forms.Application.DoEvents()
DirName = StripNulls(WFD.cFileName)
If (DirName <> ".") And (DirName <> "..") And (DirName <> "") Then
Dim FileAttributes As Integer = GetFileAttributesW("\\?\UNC\" & path & "\" & DirName)
If FileAttributes And FILE_ATTRIBUTE_DIRECTORY Then
dirNames(nDir) = DirName
DirCount = DirCount + 1
nDir = nDir + 1
ReDim Preserve dirNames(nDir)
List1.Items.Add(path & "\" & DirName)
End If
End If
Cont = FindNextFileW(hSearchEx, WFD)
Loop
Cont = FindClose(hSearchEx)
If Cont = False Then
MsgBox("Error: " + Str(GetLastError))
End If
End If
End Function
Private Sub Go_cmd_Click(ByVal eventSender As System.Object, ByVal eventArgs As System.EventArgs) Handles Go_cmd.Click
Dim SearchPath, FindStr As String
Dim FileSize As Long
Dim NumFiles, NumDirs As Long
System.Windows.Forms.Cursor.Current = System.Windows.Forms.Cursors.WaitCursor
List1.Items.Clear()
SearchPath = Text1.Text
FindStr = Text2.Text
FileSize = FindFilesAPI(SearchPath, FindStr, NumFiles, NumDirs)
System.Windows.Forms.Cursor.Current = System.Windows.Forms.Cursors.Default
End Sub
Private Sub Quit_cmd_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Quit_cmd.Click
End
End Sub
End Class
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May I ask to what end are you doing this? Why go through all of this trouble when the functionality of it is wrapper in the System.Io.FileInfo class?
Your return type for the Declare is wrong. You've got it as Long when it returns an Int32.
You may want to look at this[^] before proceeding. You don't need to specifically say your using the W version. The declare on the linked page will selected the W version if its available.
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Dave Kreskowiak wrote: May I ask to what end are you doing this? Why go through all of this trouble when the functionality of it is wrapper in the System.Io.FileInfo class?
System.Io.FileInfo is limited to the MAX_PATH =260 barrier, as far as I can tell.
Dave Kreskowiak wrote: Your return type for the Declare is wrong. You've got it as Long when it returns an Int32.
I tried Int32, but the function returns -1 in that case. However, using Long seems completely wrong too, because the function is inside a 32bit set of libraries...win32. So it can't deal with a 64bit Long.
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treddie wrote: System.Io.FileInfo is limited to the MAX_PATH =260 barrier, as far as I can
tell.
Yeah, that's because it's the limit in Windows, not .NET. The current path limit is 248 characters and the filename limit is 260.
treddie wrote: I tried Int32, but the function returns -1 in that case. However, using Long
seems completely wrong too, because the function is inside a 32bit set of
libraries...win32. So it can't deal with a 64bit Long.
The return value is either going to be a valid file handle, or INVALID_HANDLE_VALUE if the search fails for any reaons. IIRC, INVALID_HANDLE_VALUE is 0xFFFFFFFF, -1 decimal. It's been telling that that the call to FindFirstFileEx has been failing this entire time.
Check the return value before you try to use it. If it's -1, call GetLastError for the error code and it'll give you a clue as to why it failed.
But, I think you're wasting your time doing it the really hard way.
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Dave Kreskowiak wrote: that's because it's the limit in Windows, not .NET. The current path limit is 248 characters and the filename limit is 260.
But there are easy ways to accidentally create pathnames much much longer than that. When I try the FileInfo class, I run into that barrier. FindFirstFileEx() allows me to get around that problem. I have that working fine. But the Unicode part of it is what is biting me.
Incidentally, I also found through tests that the TRUE limit for Windows, is 240 characters max. When you subtract the 8.3name from the 260 and get 248, you still have to remove another 3 for the root folder...That leaves you with 245, but then you cannot use another 5 characters. This may be a bug in Windows, but in some cases, if you try to go beyond 240, you can open/save a file OK, even move it or change its name, but you may not be able to right-click it without crashing Windows and forcing it to restart. Fortunately, you do not lose any of your running apps, but all the desktop windows you had open, get closed.
UPDATE: Error code is 2, file not found. Which repeats what the returned value (-1)of the function says. So no help from GetLastError, there. 
modified 4-Jun-13 17:57pm.
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I found at least part of the problem. A string variable cannot contain Unicode characters. So Dim lpFileName_str As String = "\\?\UNC\" & path & "\*" will not work and comes back with, for example, "\\?\UNC\d:\?????????\*". Now I think I see why the string parameter needs to be changed to a pointer to the path, rather than a string representing the path.
Also, when I put the path into memory, and then retrieve it, everything is correct except the "\*" at the end...It gets interpreted as "[foreign character]*". So I think I'm finally on to at least part of the solution. I'll take a look at how to handle backslashes in Unicode strings and see what happens. That also explains why the return value from the function was "-1", file not found.
modified 4-Jun-13 18:28pm.
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Bummer...It's in some form of C. I'm not a C guy. I can struggle through it and eventually figure it out, but the hardest part is converting to vb and getting the function declarations correct. One oddity in his code, is I did not see any references to FindFirstFileEx()...Only FindFirstFile() which cannot deal with wide path names.
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treddie wrote: string variable cannot contain Unicode characters
Considering every single string in .NET is stored as Unicode, that statement is not true. The encoding is UTF-16.
treddie wrote: for example, "\\?\UNC\d:\?????????\*
The problem with what your looking at is that not every font has glyphs for every Unicode character, so you get boxes for those. In addition, if the string is being displayed by a control or other rendering device that doesn't support the encoding, characters that are not recognized are replaced with question marks. Read this[^].
treddie wrote: Now I think I see why the string parameter needs to be changed to a pointer to
the path, rather than a string representing the path
Hehe. You never pass a "string". Strings are always passed by pointer. You can only put one value, per parameter, on the stack when function call is made. In the case of strings, or other object that is not an intrinsic type, it's always a pointer.
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Dave Kreskowiak wrote: string variable cannot contain Unicode characters
Yah, that was sloppy reasoning on my part. Although, I also can't explain why I was getting inconsistent behavior in what was being reported in the string. Sometimes, when I would pass the pathname to the string, it would come back with ?'s. So without having a stable situation that I can depend on, I can't come to any conclusion on what that was all about. Especially since I can't duplicate the problem.
But now, what I have found is that the string holds the foreign characters just fine, but something odd happens when I send the string to an RTB and a plain TextBox. The RTB displays "\*" as "<foreign char="">*", but the TextBox had no problem at all and correctly shows, "\*". But if I hover my mouse over the "rtb1.text =" statement in the code, it reads fine! Weird.
Dave Kreskowiak wrote: You never pass a "string".
But why do they declare strings in any function that accepts them? I've used ANSI strings before with no problem, just as MSDN suggests. The headaches happen when I get to Unicode strings.
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treddie wrote: But why do they declare strings in any function that accepts them?
Because you're definfing the TYPE of the pointer. What kind of object does it point to? What are the rules for incrementing that pointer if needed??
If you go back to C, a "string" in it's most basic form is just a pointer to an array of type char (character). Under Windows, you can have ASCII strings and wide-character strings. Incrementing the pointer for an ASCII character just adding 1 to the pointer, but, for multi-byte characters, such as Unicode, you increment the pointer by 2 or more.
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treddie wrote: I also found through tests that the TRUE limit for Windows, is 240 characters
max.
Not quite. A fully qualifed filePATH to a file (including filename) is 248 characters max. A fileNAME (with no path information at all) is 260 characters max. Think of setting the "current directory" first before trying to access a file with a name like that. That's one way to get a filepath longer than the 248 character limit.
treddie wrote: This may be a bug in Windows
Considering that code has been around for, literally, decades, its not a bug. These are hardcoded limits in NTFS.
modified 4-Jun-13 18:58pm.
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Dave Kreskowiak wrote: I also found through tests that the TRUE limit for Windows, is 240 characters
max.
I'm not so sure about that, Dave. I ran some extensive tests many months ago when working on this program and found that there are 4 Windows limits. Their numbers are as follows, according to MS:
Folder name = 260 characters
File name (w/ extension) = 260 characters
Folder path w/o file name = 260 characters
Full path w/ filename = 260 characters
Obviously you can't have 260 in all categories so it's a matter of whatever the actual amounts are for each category, that they don't exceed any of the 4 limits.
At any rate, I tested all 4 cases and found that when you subtract out the twelve 8.3-filename chars, the 3 root characters, and the null character at the end of any path (all the characters the user has no control over), you are left with at that point only 244 characters, including backslashes, that you can play with. But, you have to actually limit yourself to 240 maximum, user-controlled characters to prevent the Windows crash on folder/file name right-click -> properties. I think that last case classifies as a bug in that your Windows session gets trashed if you go over 240 characters when getting a file's properties.
This was true in my tests for both WinXP (latest SP), and Win7 (6.1.7600 Build 7600), although the manner of the crash was different for each system. The WinXP crash was really bad and would hang the computer.
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Actually, NTFS is not at all that limited. It's just that the kernel32.dll API interface is limited to those path limits.
From MSDN, CreateFile page:
In the ANSI version of this function, the name is limited to MAX_PATH characters. To extend this limit to 32,767 wide characters, call the Unicode version of the function and prepend "\\?\" to the path. For more information, see Naming Files, Paths, and Namespaces.
By adding \\?\ you tell the kernel32 API to NOT do any parsing or processing on the path, and instead pass it directly on to the filesystem driver. From MSDN page on Naming Files, Paths, and Namespaces (Windows):
For file I/O, the "\\?\" prefix to a path string tells the Windows APIs to disable all string parsing and to send the string that follows it straight to the file system.
But not all functions can work with the extended paths, because some functions inherently need to do processing on the path.
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Yeah, I knew that. Slip of the brain when I typed it.
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OK, I'm finally getting this to work. I took the suggestion more seriously that GetLastError() might provide some insight into the problem. It wasn't anything that explicitly told me what was wrong, but it did cause me to take a much closer look at all of my declarations, and realizing that using "\\?\UNC\" was not correct...It needs to be just "\\?\".
But also took to heart your comments on strings and pointers. In that regard, I found some typing problems here and there, and missed some lines that were still not rewritten for pointers.
I'll post the resulting code here, shortly, after I copy my test code over to my final demo program and fix some remaining issues.
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One hickup...I need to deal with a C type, LPWSTR. When I research how to get this in vb.Net, I do not find any consistent explanation of how to deal with marshaling unmanaged types. There are no real-world examples and what MSDN offers is cryptic at best. Here is my best guess that does not show any syntax errors:
Dim LPWSTR As UnmanagedType
Dim MyUnicodePointer As New MarshalAsAttribute(LPWSTR)
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An LPWSTR is just a Long Pointer to a Wide character String. You're just marshalling a normal string from .NET to the function your calling. Usually, you don't have to do anything special in your function Declaration other than tell it that the paramter is a String.
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