Access 2003 - How to display an image from url? - vba

I'm working on a Access 2003 Form Report project.
I couldn't find a solution to create a QR CODE in Access 2003 Form Report.
So, I add an image/picture object to form but it does work only with local path images.
Is there any way to use it as getting pictures from a web link?
Basicly, i want to display a dynamic image from web link at Access Report Form.
Here is an example link for image: https://chart.googleapis.com/chart?cht=qr&choe=UTF-8&chs=200x200&chl=https://www.google.com

You can use the method used in my project VBA.PictureUrl using this function:
' Download (picture) file from a URL of a hyperlink field to a
' (temporary) folder, and return the full path to the downloaded file.
'
' This can be used as the control source for a bound picture control.
' If no Folder is specified, the user's IE cache folder is used.
'
' Typical usage in the RecordSource for a form or report where Id is
' the unique ID and Url is the hyperlink field holding the URL to
' the picture file to be displayed:
'
' - to a cached file where parameter Id is not used:
'
' Select *, UrlContent(0, [Url]) As Path From SomeTable;
'
' - or, where Id is used to create the local file name:
'
' Select *, UrlContent([Id], [Url], "d:\somefolder") As Path From SomeTable;
'
' Then, set ControlSource of the bound picture control to: Path
'
' 2017-05-28. Gustav Brock, Cactus Data ApS, CPH.
'
Public Function UrlContent( _
ByVal Id As Long, _
ByVal Url As String, _
Optional ByVal Folder As String) _
As Variant
Const NoError As Long = 0
Const Dot As String = "."
Const BackSlash As String = "\"
Dim Address As String
Dim Ext As String
Dim Path As String
Dim Result As String
' Strip leading and trailing octothorpes from URL string.
Address = HyperlinkPart(Url, acAddress)
' If Address is a zero-length string, Url was not wrapped in octothorpes.
If Address = "" Then
' Use Url as is.
Address = Url
End If
If Folder = "" Then
' Import to IE cache.
Result = DownloadCacheFile(Address)
Else
If Right(Folder, 1) <> BackSlash Then
' Append a backslash.
Folder = Folder & BackSlash
End If
' Retrieve extension of file name.
Ext = StrReverse(Split(StrReverse(Address), Dot)(0))
' Build full path for downloaded file.
Path = Folder & CStr(Id) & Dot & Ext
If DownloadFile(Address, Path) = NoError Then
Result = Path
End If
End If
UrlContent = Result
End Function
Your example:

Related

How to get the FolderID from Google Drive folders using Chilkat DLL

Im using the ChilKat to develop a tool using VB.NET, that performs a single file upload to my google drive account.
Im able to get the folderID within a root folder, but im struggling to get the folderID if there is a path of folders.
At this moment the argument FolderPath is not being used (i will, when i uncover how to properly get the FolderID). For now, i can get the "Nova" folder id, but none of the other folders within the following tree:
Is there an easier way to get the folderID from GoogleDrive?
I would also like to create the path of folders on Google Drive, in case they dont exist.
I never worked with JSON or HTTP requests, so im kind of lost here.
Any help would be mostly appreciated!
Thanks in advance!
Private Function FolderID(ByVal FolderPath As String) As String
Dim rest As New Chilkat.Rest
' Connect using TLS.
Dim success As Boolean = rest.Connect("www.googleapis.com", 443, True, True)
' Provide the authentication credentials (i.e. the access token)
Dim gAuth As New Chilkat.AuthGoogle
gAuth.AccessToken = M_AccessToken
rest.SetAuthGoogle(gAuth)
Dim json As New Chilkat.JsonObject
json.EmitCompact = False
' Get the folder Testes folder that is in the Google Drive root.
rest.AddQueryParam("q", "'root' in parents and name='Testes'")
Dim jsonResponse As String = rest.FullRequestNoBody("GET", "/drive/v3/files")
If Not rest.LastMethodSuccess Then
Return rest.LastErrorText
Exit Function
End If
json.Load(jsonResponse)
rest.ClearAllQueryParams()
' Now that we know the ID for the Testes directory, get the id for the folder Nova having Testes as the parent.
Dim sbQuery As New Chilkat.StringBuilder
sbQuery.Append("name = 'nova' and '")
sbQuery.Append(json.StringOf("files[0].id"))
sbQuery.Append("' in parents")
rest.AddQueryParamSb("q", sbQuery)
jsonResponse = rest.FullRequestNoBody("GET", "/drive/v3/files")
If Not rest.LastMethodSuccess Then
Return (rest.LastErrorText)
Exit Function
End If
json.Load(jsonResponse)
Return json.StringOf("files[0].id")
End Function
I managed a way by performing iterative requests.
Don't know if this is the correct way, but it works...
Here's the code, now using the FolderPath with format /folder1/folder2/folderN
Private Function GetFolderID(ByVal FolderPath As String) As String
Dim Rest As New Chilkat.Rest
' Connect to Google APIs server
Dim Connected As Boolean = Rest.Connect("www.googleapis.com", 443, True, True)
If Not Connected Then
Return "Error attempting to connect: " & Rest.ConnectFailReason
Exit Function
End If
' Provide the Access token
Dim GAuth As New Chilkat.AuthGoogle
GAuth.AccessToken = M_AccessToken
Rest.SetAuthGoogle(GAuth)
' Instance to JSON object
Dim JSON As New Chilkat.JsonObject
JSON.EmitCompact = False
' Parse the provided path and split to array
Dim ParseFolder As String = Strings.Right(FolderPath, Len(FolderPath) - 1)
Dim Folders As String() = Split(ParseFolder, "/")
' Get the root folder that is in the Google Drive folders structure
Rest.AddQueryParam("q", "'root' in parents and name='" & Folders(0) & "'")
Dim Response As String = Rest.FullRequestNoBody("GET", "/drive/v3/files")
If Not Rest.LastMethodSuccess Then
Return Rest.LastErrorText
Exit Function
End If
JSON.Load(Response)
'Iterate on the folders to get the last folder's id
Rest.ClearAllQueryParams()
For i = 1 To Folders.Length - 1
Dim sbQuery As New Chilkat.StringBuilder
sbQuery.Append("name = '" & Folders(i) & "' and '")
sbQuery.Append(JSON.StringOf("files[0].id"))
sbQuery.Append("' in parents")
Rest.AddQueryParamSb("q", sbQuery)
Response = Rest.FullRequestNoBody("GET", "/drive/v3/files")
If Not Rest.LastMethodSuccess Then
Return Rest.LastErrorText
Exit Function
End If
JSON.Load(Response)
Next
' Get the folder id
Return JSON.StringOf("files[0].id")
End Function

Uploading File To Website

I am still a beginner with VBA, so if you need further explanation or I am not describing my problem correctly please let me know.
I am trying to achieve the following:
Upload a file from my computer to a website (You can only try to upload if you login, so sadly I cannot share a link)
In order to achieve this I need to do three things:
1) Click the "Upload" Button
2) Insert the Filepath into the search field of the PopUp Window
3) Click the "Open" Button
The website looks like this:
The PopUp Window looks like this:
The HTML code of the upload field is the following:
<div class="button-wrapper">
<input class="design-file-input" type="file">
<a class=" button prio1" href="javascript:void(0);">Design hochladen</a>
</div>
I guess there might be two solutions two my problem, however, I am not able to realize my plans.
IDEA 1
Somehow get the filepath into the input field and the page to download it
Therefore I tried the vba following VBA codes:
objIE.document.getElementsByClassName("design-file-input")(0).Value
objIE.document.getElementsByClassName("design-file-input")(0).innerText
And then try to somehow make the website submit my entry.
IDEA 2
Click the "Design Hochladen" Button.
objIE.document.getElementsByClassName("button-wrapper")(0).Click
But then the PopUp window comes up and I don't know how to control it with VBA
I am happy to hear and try your suggestions!! If you need any further details, just let me know! Thank you so much if you can give me any advice
Directly assigning the file path to the value of that specific HTML element does not work. A while ago, I had the same issue (automatically passing a file to an upload file dialog). After a long googling session, I found following solution. Unfortunately, I could not find the link from where I took this answer. In case I come accross the website, I will share the link with you:
Dim FilePath As String
Dim FileName As String
FilePath = Environ$("temp") & "\"
FileName = "test_file_for_upload" & ".xlsx"
UploadFile DestURL, FilePath & FileName, "file" 'Usage
'******************* upload - begin
'Upload file using input type=file
Public Sub UploadFile(DestURL As String, FileName As String, _
Optional ByVal FieldName As String = "File")
Dim sFormData As String, d As String
'Boundary of fields.
'Be sure this string is Not In the source file
Const Boundary As String = "---------------------------0123456789012"
'Get source file As a string.
sFormData = GetFile(FileName)
'Build source form with file contents
d = "--" + Boundary + vbCrLf
d = d + "Content-Disposition: form-data; name=""" + FieldName + """;"
d = d + " filename=""" + FileName + """" + vbCrLf
d = d + "Content-Type: application/upload" + vbCrLf + vbCrLf
d = d + sFormData
d = d + vbCrLf + "--" + Boundary + "--" + vbCrLf
'Post the data To the destination URL
IEPostStringRequest DestURL, d, Boundary
End Sub
'sends URL encoded form data To the URL using IE
Sub IEPostStringRequest(URL As String, FormData As String, Boundary As String)
'Create InternetExplorer
Dim WebBrowser: Set WebBrowser = CreateObject("InternetExplorer.Application")
'You can uncoment Next line To see form results
WebBrowser.Visible = True
'Send the form data To URL As POST request
Dim bFormData() As Byte
ReDim bFormData(Len(FormData) - 1)
bFormData = StrConv(FormData, vbFromUnicode)
WebBrowser.navigate URL, , , bFormData, _
"Content-Type: multipart/form-data; boundary=" + Boundary + vbCrLf
Do While WebBrowser.Busy
' Sleep 100
DoEvents
Loop
'WebBrowser.Quit
End Sub
'read binary file As a string value
Function GetFile(FileName As String) As String
Dim FileContents() As Byte, FileNumber As Integer
ReDim FileContents(FileLen(FileName) - 1)
FileNumber = FreeFile
Open FileName For Binary As FileNumber
Get FileNumber, , FileContents
Close FileNumber
GetFile = StrConv(FileContents, vbUnicode)
End Function
'******************* upload - end
The third argument "file" denotes the ID of the HTML element which needs to be triggered.
Hope this solution workds for you as well

Saving files from OLE Objects (Access) to disc

I have an MS SQL Database from a customer with an Access Application.
This application stores files within this MS SQL database.
I tried to just get the bytes from the database and just save them to the disk.
With some of the files this works and with some it does not.
(images don't work, zips work, wordfiles are to open but word has to recover them)
I found out that Access saves the files within an OLE Object.
So i need to get out the Original Files from the OLE Object!
It seems that this is quite difficult.
I tried to find a .NET library which can seperate the files from the OLE Object.. found nothing...
Now i am trying to get the files out with Access...
It seems that i neet a getChunk Function to do that...
Found this page with a WriteBlob Code... it is said that it would to what i need..
https://support.microsoft.com/en-us/help/210486/acc2000-reading--storing--and-writing-binary-large-objects-blobs
Now i can write Files to the Harddisc... but the files are still not able to open!
Something's wrong here...
My complete VBA Code is this:
Option Compare Database
Const BlockSize = 32768
Sub xxx()
Dim id As Integer
Debug.Print "****************************************************"
Debug.Print "****************************************************"
Debug.Print "****************************************************"
Debug.Print "****************************************************"
Dim unnoetig As Variant
Dim dok() As Byte
Dim sql As String
sql = "select top 1 idCaseDetail, idCase, Dokument from dbo_law_tbl_CaseHistory where idCaseDetail = ""1"""
Dim rst As DAO.Recordset
Set rst = CurrentDb.OpenRecordset(sql)
If Not rst.EOF Then
Do While Not rst.EOF
Debug.Print "idcasehistory: " & rst.Fields(0)
Debug.Print "idcase: " & rst.Fields(1)
If Not IsNull(rst.Fields(2).Value) Then
dok = rst.Fields(2)
unnoetig = WriteBLOB(rst, "Dokument", "c:\temp\ole.doc")
End If
rst.MoveNext
Loop
End If
End Sub
'**************************************************************
' FUNCTION: WriteBLOB()
'
' PURPOSE:
' Writes BLOB information stored in the specified table and field
' to the specified disk file.
'
' PREREQUISITES:
' The specified table with the OLE object field containing the
' binary data must be opened in Visual Basic code and the correct
' record navigated to prior to calling the WriteBLOB() function.
'
' ARGUMENTS:
' T - The table object containing the binary information.
' sField - The OLE object field in table T containing the
' binary information to write.
' Destination - The path and filename to write the binary
' information to.
'
' RETURN:
' The number of bytes written to the destination file.
'**************************************************************
Function WriteBLOB(T As DAO.Recordset, sField As String, _
Destination As String)
Dim NumBlocks As Integer, DestFile As Integer, i As Integer
Dim FileLength As Long, LeftOver As Long
Dim FileData As String
Dim RetVal As Variant
On Error GoTo Err_WriteBLOB
' Get the size of the field.
FileLength = T(sField).FieldSize()
If FileLength = 0 Then
WriteBLOB = 0
Exit Function
End If
' Calculate number of blocks to write and leftover bytes.
NumBlocks = FileLength \ BlockSize
LeftOver = FileLength Mod BlockSize
' Remove any existing destination file.
DestFile = FreeFile
Open Destination For Output As DestFile
Close DestFile
' Open the destination file.
Open Destination For Binary As DestFile
' SysCmd is used to manipulate the status bar meter.
RetVal = SysCmd(acSysCmdInitMeter, _
"Writing BLOB", FileLength / 1000)
' Write the leftover data to the output file.
FileData = T(sField).GetChunk(0, LeftOver)
Put DestFile, , FileData
' Update the status bar meter.
RetVal = SysCmd(acSysCmdUpdateMeter, LeftOver / 1000)
' Write the remaining blocks of data to the output file.
For i = 1 To NumBlocks
' Reads a chunk and writes it to output file.
FileData = T(sField).GetChunk((i - 1) * BlockSize _
+ LeftOver, BlockSize)
Put DestFile, , FileData
RetVal = SysCmd(acSysCmdUpdateMeter, _
((i - 1) * BlockSize + LeftOver) / 1000)
Next i
' Terminates function
RetVal = SysCmd(acSysCmdRemoveMeter)
Close DestFile
WriteBLOB = FileLength
Exit Function
Err_WriteBLOB:
WriteBLOB = -Err
Exit Function
End Function
Do you have any suggestions?
Important to say is:
It is an MS SQL Database... not an Access Database.. there are some tools which maybe could word with access-Databases.. but not mit ms sql
Is there a .NET way or an VBA way to save the files to disc?
An easy alternative to using DAO for saving OLE objects, is to use the ADODB.Stream object:
Public Sub SaveOLEObject(OleObjectField As Field, Filelocation As String)
Dim adoStream As Object 'ADODB.Stream
Set adoStream = CreateObject("ADODB.Stream")
adoStream.Type = 1 'adTypeBinary
adoStream.Open
adoStream.Write OleObjectField.Value
adoStream.SaveToFile Filelocation, adSaveCreateOverWrite
adoStream.Close
End Sub
Call it:
SaveOLEObject(rst.Fields("Dokument"), "c:\temp\ole.doc")
Note that, of course, your documents might just be corrupt, and that might explain the problem.
If your objects are stored in SQL Server, I'd prefer directly opening an ADO recordset containing the binary data from SQL server over creating a linked table and opening a DAO recordset from the linked table.
In Access, create a corresponding Access Form with all relevant fields. Use the VBA code provided in the link and you should be able to export some of the most common file types in an automated fashion. Good luck.
https://medium.com/#haggenso/export-ole-fields-in-microsoft-access-c67d535c958d

File extension validation

This searches for the end of a file name removes it's current file type of .docm and converts it to a .docx. Works great.
ActiveDocument.SaveAs2 Left(ActiveDocument.Name, InStrRev(ActiveDocument.Name, ".") - 1), WdSaveFormat.wdFormatXMLDocument
However, I noticed a little bug. If there is a . in the file name, it finds that first and obviously creates a file that is incorrect.
For example:
TestFileV1.2AlexTest.docm
Becomes the file
TestFileV.2AlextTest Where the new file type is a .2ALEXTEST file.
Kind of a funny error, but still a bug none the less.
Best course of action for validation?
Thanks!
Try the VBA.Strings.Split() function, which splits a string into an array.
Split the File name on '.' and the last element in the array will be your extension:
Public Function GetExtension(FileName As String) As String
'Returns a file's extension
' This does not go to the filesystem and get the file:
' The function parses out the string after the last '.'
' Useful for situations where a file does not yet exist
' Nigel Heffernan Excellerando.Blogspot.com
' **** THIS CODE IS IN THE PUBLIC DOMAIN ****
'Print GetExtension("C:\Temp\data.txt1.docx")
'Returns docx
Dim arrayX() As String
Dim iLast As Integer
arrayX = Split(FileName, ".")
iLast = UBound(arrayX)
GetExtension = arrayX(iLast)
Erase arrayX
End Function
If you don't care about readability, the quick-and-dirty answer is:
strExt = Split(strFile, ".")(UBound(Split(strFile, ".")))
However... I think you're looking for something more sophisticated than a string parser to extract the file extension.
Are you actually looking to validate the file extension?
I'm not coding up a registry lookup for the ShellExt application command to open your file, but I had a closely-related issue to yours a year or two ago, when I needed to populate a file dialog's filter list with a list of arbitrary file extensions.
It doesn't 'validate' as such, but unknown extensions will return a string containing 'unknown file type', and you can test for that:
VBA and the Registry: Returning a File Type from a File Extension
Public Function GetExtensionType(strExt As String) As String
' Return a file extension type descriptor, if the OS knows it
' Parses out the string after the last "." and reads the registry
' GetExtensionType("txt") Returns 'Text Document'
' GetExtensionType("SystemORA.user.config") 'XML Configuration File'
' GetExtensionType("Phishy.vbs") 'VBScript Script File'
' Nigel Heffernan Excellerando.Blogspot.com
' **** THIS CODE IS IN THE PUBLIC DOMAIN ****
On Error GoTo ErrSub
Dim strType As String
Dim strTyp1 As String
Dim strTyp2 As String
strExt = Trim(strExt)
' Set a default return: if an error is raised, return this value
GetExtensionType = Trim(strExt & " (unknown file type)")
strExt = Split(strExt, ".")(UBound(Split(strExt, "."))) '
If strExt = "" Then
Exit Function
End If
With CreateObject("WScript.Shell")
' This will go to error if there's no key for strExt in HKCR
strTyp1 = .RegRead("HKCR." & strExt & "\")
If strTyp1 = "" Then
strType = strExt & " File"
Else
' This value isn't very readable, eg: Access.ACCDEFile.14
' But we can use it to retrieve a descriptive string:
strTyp2 = .RegRead("HKCR\" & strTyp1 & "\")
If strTyp2 = "" Then
' So we didn't get a descriptive string:
' Parse some readability out of strType1:
strType = strTyp1
strType = Replace(strType, "File", " File")
strType = Replace(strType, ".", " ")
Else
strType = strTyp2
End If
End If
End With
If strType <> "" Then
GetExtensionType = strType
End If
ExitSub:
Exit Function
ErrSub:
Resume ExitSub
End Function
I made it error-tolerant but I didn't bother idiot-proofing it because someone, somewhere, is building a better idiot; and it's entirely possible that the user was actually right insofar as there really are files called that, and my system didn't have a registry entry for the file type in question.
There is an obvious source of errors in the code: GetExtensionType("docx") will give you 'Microsoft Word Document' on an English-Language workstation. If your user base are working with other languages and locales, they will see the descriptive name 'Microsoft Word Document' in their chosen language; and any validation logic you've coded up will fail to match that string (unless, of course, your string literals are internationalised in a conditional compiler block).
So any validation against a predefined application name or file type needs to be at the language-independent layer of the registry, using 'strTyp1' from the root instead of the locale-dependent strings passed into 'strTyp2'.
Use the FileSystemObject from the Scripting Runtime - it has a .GetBaseName() method to extract the basename from a file path:
'Early bound (reference to Microsoft Scripting Runtime):
Dim fso As New FileSystemObject
ActiveDocument.SaveAs2 fso.GetBaseName(ActiveDocument.Name), WdSaveFormat.wdFormatXMLDocument
'Late bound:
Dim fso As Object
Set fso = CreateObject("Scripting.FileSystemObject")
ActiveDocument.SaveAs2 fso.GetBaseName(ActiveDocument.Name), WdSaveFormat.wdFormatXMLDocument
You can also retrieve the extension with the .GetExtensionName() method, the path with .GetParentFolderName(), and the drive letter with GetDriveName() (which also works with UNC paths).
If you need to find the registered name of the extension in the current Windows install, you can either use the registry method #Nile answered with or an API call to AssocQueryStringA:
Const ASSOCSTR_FRIENDLYDOCNAME = 3
Private Declare Function AssocQueryString Lib "shlwapi.dll" _
Alias "AssocQueryStringA" ( _
ByRef Flags As Long, _
ByVal str As Long, _
ByVal pszAssoc As String, _
ByVal pszExtra As String, _
ByVal pszOut As String, _
ByRef pcchOut As Long) As Long
Sub Main()
Dim buffer As String
buffer = String$(255, " ")
Dim hresult As Long
hresult = AssocQueryString(0, ASSOCSTR_FRIENDLYDOCNAME, ".docm", _
vbNullString, buffer, 255)
If hresult = 0 Then
'Should be something like "Microsoft Word Macro-Enabled Document"
Debug.Print Trim$(buffer)
End If
End Sub
Note that you can also retrieve addition information about the associated file type by passing different values for the str parameter. See the ASSOCSTR enumeration.

File Icons and List view

How to retrieve file icons associated with the file types and add them with the items of Listview in vb.net
I read about SHGetFileInfo but I didn't understand anything from that
please give me solution or please explain me ho system works with the .net controls in details
Having looked up SHGetFileInfo I can see why you're confused by it, but I think it might be slightly overkill for what I think you're trying to do i.e. enumerating the contents of a folder and adding items to the Listview.
If we have a form that contains a ListView and an ImageList, with the two related by having the ListView's LargeImageList property set to the ImageList, then here's how we put the contents of a folder into the ListView with the icons coming from the associated EXE file for each file.
Imports System.IO
Imports System.Drawing
Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
Dim dirInfo As DirectoryInfo
Dim fileInfo As FileInfo
Dim exePath As String
Dim exeIcon As Icon
dirInfo = New DirectoryInfo(path_to_some_folder
'We use this For...Each to iterate over the collection of files in the folder
For Each fileInfo In dirInfo.GetFiles
'We can only find associated exes by extension, so don't show any files that have no extension
If fileInfo.Extension = String.Empty Then
Else
'Use the function to get the path to the executable for the file
exePath = GetAssociatedProgram(fileInfo.Extension)
'Use ExtractAssociatedIcon to get an icon from the path
exeIcon = Drawing.Icon.ExtractAssociatedIcon(exePath)
'Add the icon if we haven't got it already, with the executable path as the key
If ImageList1.Images.ContainsKey(exePath) Then
Else
ImageList1.Images.Add(exePath, exeIcon)
End If
'Add the file to the ListView, with the executable path as the key to the ImageList's image
ListView1.Items.Add(fileInfo.Name, exePath)
End If
Next
End Sub
GetAssociatedProgram comes from developer.com
Public Function GetAssociatedProgram(ByVal FileExtension As _
String) As String
' Returns the application associated with the specified
' FileExtension
' ie, path\denenv.exe for "VB" files
Dim objExtReg As Microsoft.Win32.RegistryKey = _
Microsoft.Win32.Registry.ClassesRoot
Dim objAppReg As Microsoft.Win32.RegistryKey = _
Microsoft.Win32.Registry.ClassesRoot
Dim strExtValue As String
Try
' Add trailing period if doesn't exist
If FileExtension.Substring(0, 1) <> "." Then _
FileExtension = "." & FileExtension
' Open registry areas containing launching app details
objExtReg = objExtReg.OpenSubKey(FileExtension.Trim)
strExtValue = objExtReg.GetValue("").ToString
objAppReg = objAppReg.OpenSubKey(strExtValue & _
"\shell\open\command")
' Parse out, tidy up and return result
Dim SplitArray() As String
SplitArray = Split(objAppReg.GetValue(Nothing).ToString, """")
If SplitArray(0).Trim.Length > 0 Then
Return SplitArray(0).Replace("%1", "")
Else
Return SplitArray(1).Replace("%1", "")
End If
Catch
Return ""
End Try
End Function
At the end of all of that, when you run this code on this folder:
alt text http://www.philippursglove.com/stackoverflow/listview1.png
you should get:
alt text http://www.philippursglove.com/stackoverflow/listview2.png
If you know the file name of the file whose icon you want, you can use the System.Drawing.Icon.ExtractAssociatedIcon function for that purpose. e.g.
Icon ico = System.Drawing.Icon.ExtractAssociatedIcon(#"C:\WINDOWS\system32\notepad.exe");
You can also refer to my answer to a related question for more implementation details.