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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.
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