I need some help creating a simple dll

I need some help creating a simple dll

• scorange

  Well if the assembly/dll does not exist and "AddNumbers" is a function in that DLL and you call it, you will get an exception which you try to execute that function, since you are importing the namespace it will import but when trying to access that class/function in that DLL, it will throw a filenotfound exception if the file does not exist, so that should work.

  As a test, just copy your .exe file into a different directory, in its own on your computer and run it. Now press Button1. you should see a messagebox now, with that the exception message since this will be your catch block being executed

  
  
  

• Steven Galione

  And actually as a note to others. I noticed that I had to have the dll in my release folder other wise I'd get a compile error.
  
  
  

• robertje

  Yeah I can create Classes and Application.
  Oh hey, wadda ya know ! That worked nicely! Actually I has to change the Function to Shared Function though but it works!
  
  Thank you ahmedilyas!
  
  
  

• Tyrael Tong

  Sure. I'm wondering if I could add in and IOException as well...
  
  Imports FVxDll.Class1
  
  Public Class Form1
  
      Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
          Try
              TextBox3.Text = AddNumbers(TextBox1.Text, TextBox2.Text)
          Catch Ex As Exception
              MsgBox(Ex.Message)
          End Try
      End Sub
  
  End Class
  
  
  
  

• BrianYDP

  can you tell us what doesnt work Have you been able to create the DLL in VB.NET

  I'm not sure about the Express Editions however when I had created a simple DLL to add 2 numbers and return back the result, once the DLL was compiled, I simply added that DLL as a reference (right click on your "References" in the winforms project and go to add reference, select the browse tab and double click the DLL).

  Once added, you should be able to access that dll usually in the format of:

  DllAssemblyName.ClassName

  So you would need to create an instance of a class in that dll:

  Dim theClass as new DllName.ClassName()

   

  then access its public members like so:

  Dim result as Integer = theClass.AddNumbers(1, 2)

   

  
  
  

• reichard

  Well from what I've read a dll is just a simple class with a function. I don't want to make a use control. I have no need for a GUI. The dll should add the number. This is what I have for that... If that's how it's even supposed to look:
  
  Public Class Class1
  
  Function AddNumbers(ByVal X As Integer, ByVal Y As Integer)
  AddNumbers = X + Y
  End Function
  
  End Class
  
  I keep finding information about dlls for VB6 but when I used VB6 I still couldn't get it to work!
  
  Whether or not the dll structure is right, I still don't know how to call it in my Application. All the tutorials are about a user control for a button. And If I remember right, the MSDN Help Files on my computer have an example for that. But again. I want to make a simple dll and application that adds 2 numbers.
  
  Does this make any since I don't want to confuse any one.
  
  
  
  

• abzA

  makes perfect sense and I did just that without any problems. I'm not sure if the express edition has this but when you create a new project, do you get a template called something like "Class library" this is the one you need to make a dll. The class files are the same really, its just the project type that needs to be a library to make a DLL. if not, sure for one online in the new project dialog...if it doesnt exist then nothing much you can do as its a limit in the express edition IDE. However you can still use the VB.NET compiler, vbc.exe, in the .NET Framework directory in the Windows folder and use the command line to compile a file/project into a dll. Not entirely sure how to do this but when typed in a command prompt "vbc.exe / " after navigating to the directory it should give you a list of commands

  anyway lets do everything step by step, do you get the class library project template

  
  
  

• irl-barse

  I do; however, have one more question. If the dll doesn't exist and a user tries to use the program how can I capture that exception I tried as Try statement but that didn't work.
  
  
  

• coconut113651

  no worries, glad I could help :-)

  now if the assembly/dll does not exist then placing a try catch block on where you are trying to create the class. you should get a FileNotFound exception. What happens when you try this Can you show the code you are using

  
  
  

• TJ2007

  Right, and it give the user the option to continue, quit and/or view the details.
  Hum actually, if any of my dlls are really needed then I could make a function that checks if they exists using IO namespace.
  
  
  
• I need some help creating a simple dll