Visual Basic

How to use third party dll at runtime with help of (dll) file path and procedure name

9-Feb-09 7:55

You're going to have to start reading and testing possible solutions yourself. It does not appear to be anything wrong with your code, but with an underlying network issue.

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Dave Kreskowiak
Microsoft MVP
Visual Developer - Visual Basic
2006, 2007, 2008

kvelu.d8-Feb-09 19:16

kvelu.d

8-Feb-09 19:16

<b>Sample dll code: </b>

Public Class SWTest
Public Shared Sub kv()
MsgBox("Code Project")
End Sub
End Class

Please help me, how can i import this dll and call the procedure at runtime

Note: My windows application only have the string inputs of (dll) file path and procedure name
Example:
Input1 = "D:\SWTest.dll"
Input2 = "kv"

Thanks
KV

Re: How to use third party dll at runtime with help of (dll) file path and procedure name

MohammadAmiry8-Feb-09 19:19

Re: How to use third party dll at runtime with help of (dll) file path and procedure name

8-Feb-09 19:19

see

http://www.omegajunior.net/code/vbnet_unmanaged.html[^]

kvelu.d9-Feb-09 0:31

kvelu.d

9-Feb-09 0:31

hi,

i used your link sample, but i was got this error

Value cannot be null.
Parameter name: ptr

FYI: Please download my sample project from this link <a href="http://www.2shared.com/file/4835939/1eaac353/RunTime_Dll.html">http://www.2shared.com/file/4835939/1eaac353/RunTime_Dll.html</a>[<a href="http://www.2shared.com/file/4835939/1eaac353/RunTime_Dll.html" target="_blank" title="New Window">^</a>]

Note: Please send me any sample project attachment to my email id (to_velu@yahoo.co.in) if possible.

Re: How to use third party dll at runtime with help of (dll) file path and procedure name

kvelu.d9-Feb-09 0:35

kvelu.d

9-Feb-09 0:35

Download link
http://www.2shared.com/file/4835939/1eaac353/RunTime_Dll.html

Re: How to use third party dll at runtime with help of (dll) file path and procedure name

MohammadAmiry9-Feb-09 1:11

Re: How to use third party dll at runtime with help of (dll) file path and procedure name

9-Feb-09 1:11

The method you are using (and was suggested in my link) works for ActiveX Dlls and OCX objects.

First, have your class library a module not a class:

Public Module TestDll
    Public Sub Test()
        MsgBox("Hi")
    End Sub
End Module

Then use LoadLibrary to load the dll.

Delegate Sub Tst() 
.
.
.
 Static dll_loaded As Boolean, dll_handle As Int32,  fn As tst
 dll_handle = LoadLibrary("Testdll.dll")
 msgfn = GetProcAddress(dll_handle, "Test")
 msgfn.Invoke()

By the way, why do you want to late-bind?
Try using

Declare

which makes it much faster and more reliable!

Steven J Jowett8-Feb-09 22:29

Steven J Jowett

8-Feb-09 22:29

I believe you need to read up on Late Binding[^]

Steve Jowett
-------------------------
Real programmers don't comment their code. If it was hard to write, it should be hard to read.

What could cause not to show some international characters in the listview if it was showing before?

JUNEYT8-Feb-09 8:53

JUNEYT

8-Feb-09 8:53

Hi,

What would you think if the listview is not showing the Turkish characters in the rows after placing a splitter container and moving listview into splitter's one side panel and setting the fonts same for both controls. This problem turned in to a disaster for me. Eventough I used UTF encoding to the strings the problem haven't changed.

Here how I tested the problem to make sure the turkish characters were diplayed in the listview properly.
I created a new form and placed a listview with one column and then I listed the file mames which contained some turkish characters in this column. It showed perfectly. However, after adding a splitter container control on to form and moving listview inside of this container and adding a few more columns to listview did start not showing the Turkish characters anymore in the listview but strange characters.

Now I wonder what would you think about such problem and how to solve it?

Thanks for reading.

What a curious mind needs to discover knowledge is noting else than a pin-hole.

Re: What could cause not to show some international characters in the listview if it was showing before?

Steven J Jowett8-Feb-09 22:35

Steven J Jowett

8-Feb-09 22:35

Recheck the properties of your ListView. It is possible that 1 or more have reset to the defaults, when you moved the ListView control into the splitter

Steve Jowett
-------------------------
Real programmers don't comment their code. If it was hard to write, it should be hard to read.

Re: What could cause not to show some international characters in the listview if it was showing before?

JUNEYT8-Feb-09 23:34

JUNEYT

8-Feb-09 23:34

The problem remains the same I have checked to see if any property attribute set to default.

What a curious mind needs to discover knowledge is noting else than a pin-hole.

How to determine if it is a file or directory for an item under a folder? [modified]

JUNEYT8-Feb-09 7:22

JUNEYT

8-Feb-09 7:22

Hi,

How could you determine if a read item is a folder or a file in vb.net? For an instance I have read all the files under directory. At the same time there is a sub directory under the directory and I want to get its type.

Thanks.

What a curious mind needs to discover knowledge is noting else than a pin-hole.

modified on Sunday, February 8, 2009 1:54 PM

Re: How to determine if it is a file or directory for an item under a folder?

Luc Pattyn8-Feb-09 8:01

Luc Pattyn

8-Feb-09 8:01

Hi,

File attributes would tell you. Here is a C# example, I don't have it in VB.NET:

FileInfo info=new FileInfo(fileName);
attributes=info.Attributes;
bool isFolder=(attributes & FileAttributes.Directory)!=0;
...

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Re: How to determine if it is a file or directory for an item under a folder?

MohammadAmiry8-Feb-09 19:26

Re: How to determine if it is a file or directory for an item under a folder?

8-Feb-09 19:26

The equivalent vb code is:

<code>
  Dim info as New FileInfo(fileName)
  Dim isFolder As Boolean = info.Attributes And FileAttributes.Directory
</code>

MohammadAmiry8-Feb-09 19:24

How to pass a parameter to windows application form the way we can do in a web form

8-Feb-09 19:24

If IO.File.Exists(Path) Then
   'It is a file
ElseIf IO.Directory.Exists(Path) Then
   'It is a folder
End If

Naglaa Saeed8-Feb-09 0:32

Naglaa Saeed

8-Feb-09 0:32

I'm using vb.net application form
My form requests user to enter ID in text area to retreive some data for printing

I want to know is it possible to pass this ID as a paramter when I call the web application form without requesting user to submit it I mean that I will send user link of the application form with the ID as a parameter just as we do in a web form.

Re: How to pass a parameter to windows application form the way we can do in a web form

Dave Kreskowiak8-Feb-09 5:34

Re: How to pass a parameter to windows application form the way we can do in a web form

8-Feb-09 5:34

Naglaa Saeed wrote:
I mean that I will send user link of the application form

Your question doesn't make sense. There's no such thing. You cannot instantiate, or call, a windows form from a URL, at least, not in the way you're implying.

Are you asking how to call a windows form from a web form?? Or, forgetting the web analogy, are you asking how to pass a username to a login form and execute the code on the login form, without the user typing the information into the form??

A guide to posting questions on CodeProject[^]

Dave Kreskowiak
Microsoft MVP
Visual Developer - Visual Basic
2006, 2007, 2008

vaghelabhavesh8-Feb-09 10:36

vaghelabhavesh

8-Feb-09 10:36

You can use Parametrized constructor or Property if you want to pass a parameter from one Form to another.

Naglaa Saeed wrote:
I will send user link of the application form with the ID

In this case, you can use start your application with commandline argument. In main method check the argument and set the value accordingly.

Re: How to pass a parameter to windows application form the way we can do in a web form

MohammadAmiry8-Feb-09 19:31

Error in Update & Insert Statement

8-Feb-09 19:31

If I have understood you correctly, you might use commandline parameters to run your application, or as mentioned by crudeCodeYogi, by using parametrized constructors.

Vikash Yadav7-Feb-09 21:20

Vikash Yadav

7-Feb-09 21:20

Hi,

I am Using MS Access 2002 Databe & vb.net 2005 in my Project.
In My Project is Select Command working Properly, But Insert & Update Command is giving Error ("Syntex Error in Update Statement" or in Insert Error in Insert Statement.

I am using this function for update

Private Function UpdateUser(ByVal Password As String, ByVal UserID As Integer)
Try
Dim strcmd As String = "update tblLogin set Password='" + Password + "' where UserID =" & UserID.ToString
Dim cmd As New OleDbCommand(strcmd, con)
con.Open()
cmd.ExecuteNonQuery()
con.Close()
Catch ex As Exception
MsgBox(ex.Message, MsgBoxStyle.Critical, "Error Message")
End Try

Return 0
End Function

What is the solution for this

Plese Help Me.

Thanks & Regards

Form :-
Vikash Yadav

Luc Pattyn8-Feb-09 4:39

Luc Pattyn

8-Feb-09 4:39

Hi,

AFAIK if your UserID field is a string type (which your use of ToString suggests), you must enclose the value in quotes wihtin your SQL statement.

Smile | :)

Luc Pattyn [Forum Guidelines] [My Articles]

Vikash Yadav8-Feb-09 17:01

Vikash Yadav

8-Feb-09 17:01

Thanks For Sugestion.

UserID field is a autonumber type. This Function Work with SQL 2000 Properly. I want to use Access DataBase not SQL.

Thanks & Regards

Form :-
Vikash Yadav

Dave Kreskowiak8-Feb-09 5:21

8-Feb-09 5:21

Instead of using string concatenation to build the SQL statement, use parameterized queries instead. Search the articles for "SQL Injection" for examples and why it is a VERY good idea to do so. Your code, as it is now, is very broken, even though it "works".

A guide to posting questions on CodeProject[^]

Dave Kreskowiak
Microsoft MVP
Visual Developer - Visual Basic
2006, 2007, 2008

paas8-Feb-09 8:08

paas

8-Feb-09 8:08

Why is his code "very broken" from a "SQL Injection" standpoint? He is working with an Access MDB, and even if his UserID was being passed as a string, you can not concatenate queries in Access, so that does not seem to be an "injection" concern. And, since UserID is actually being passed as an integer, I do not see how a nefarious user would be able to sneak an 'Or' conditional into the where command that will automatically make the result True. What is the 'SQL Injection' issue I am missing in his query?

The potential problem I see with this code is that if 'Password' can contain single quotes, he is not escaping those single quotes in the query being built, and that would create a syntax error. Now parameterized queries would resolve that potential issue, but that can also be handled easily with a Replace statement, and without the use of parameterized queries.

Dave Kreskowiak8-Feb-09 13:18