hi,
1. in vb dlls are created with application type ActiveX dll. (select as new project -->open it)
2. u will get one class window opened.
3. u can write code in this window.
4. in project menu-->refferences
add refference to COM+ Serviece Type library.
5. for using with ADO. u need to add
microsoft activex data object library 2.5
6. set propertys of class module.
instance property - 5- multy use
mts transactionmode --> 2 RequiresTransaction
7. write following code (sample)
Public Function GetServerDate() As Date
On Error GoTo errlbl
Dim objCont As COMSVCSLib.ObjectContext
Set objCont = GetObjectContext
GetServerDate = Date
objCont.SetComplete
Set objCont = Nothing
Exit Function
errlbl:
' if we need can add log method here
objCont.SetAbort
Set objCont = Nothing
End Function
Public Function GetServerServerTime() As String
On Error GoTo errlbl
' { common for every dll
Dim objCont As COMSVCSLib.ObjectContext
Set objCont = GetObjectContext
''}
''----------------------------
' general program here. like in class module
GetServerServerTime = Time
''-----------------------------
''{ common to dll
objCont.SetComplete
Set objCont = Nothing
''}
Exit Function
'{optional}
errlbl:
' if we need can add log method here
objCont.SetAbort
Set objCont = Nothing
End Function
8. in project menu --> component tab.
select project compatability option(default)
(study abt compatability by clicking the help button in this dailog box(u can get info in less time else go for google
imp: first time u creating a dll default is correct( new GUID is created, study more abt guid in help. imp2: when u modifing code in dll. select binary compatability) )
click OK.
If u r developing dll for 3 tire architecture. u need to select server files check box.
9. then file --> make .dll.
10. open control panel->compnent services
console root->comp services-> my computers>com+ applictions
right click -> new application ->next-> select create emply application>enter new app name, select library app opt. if not server 3tire app.-> next ->finish
11. u will get a new app name in tree view. click on +
right click on components > new > component > next > select install new components > select dll file name > open > next > finish
(by drag drop also we can do it, check help for more info)
12. now u will get new dll added in component services explore.
--------------
13. now open standard vb appliction
place 2 text boxs, 2 buttons
peast following code.
Private Sub Command1_Click()
Dim obj As Dll_co_common.ClsCommon
Set obj = CreateObject("Dll_co_common.ClsCommon")
Text1.Text = obj.GetServerServerdate
Set obj = Nothing
End Sub
Private Sub Command2_Click()
Dim obj As Dll_co_common.ClsCommon
Set obj = CreateObject("Dll_co_common.ClsCommon")
Text2Text = obj.GetServerServerTime
Set obj = Nothing
End Sub
14. add refference to dll.
project menu>refferences
check new dll file name, if not found browes to add new dll to add to refference list.
15. now run ur client program.
u can also develop for database programs also.
my suggestion is go throug help in vb(msdn) dailog box, dont spend for more time to search for concept itself.
i think it will help u, for atleast starting of dll coding.
if it is not enough for ur requirement use keywork from the program to search in online sources
enjoy vb programming .... all the best my friend