In csharp or vb.net we use the using statement for reasons that we know: One can open the database and close it automatically without writing it explicitly.
I would like to do the samething in VBA
how to do it?
Are all VB.NET statement/keywords/ available in VBA ?
how to tell if a given statement is(was) known in VBA ? Is it there a library(glosary) of all VBA statements/keyword/operators ?
c#
using(var db=new MyDbContext()){
//do work here
}
vb.net
Using s = New MyDbContext()
'--..do work here
End Using
Answering just your first question, as you've hinted, Using is just syntactic sugar for calling Dispose() on an object instance which implements the IDisposable interface.
It is equivalent to
Dim s as MyDbContext
Try
s = New MyDbContext()
// ...
Finally
s.Dispose()
End Try
Since VBA doesn't support the Using sugar, and in the absence of structured Try..Catch exception handling, you'll need to explicitly call Dispose() on all paths which control the lifespan of the object (MyDbContext in your case). In which case you may as well have just used .Close()
There is no VBA equivalent to the Using statement.
The VBA developer documentation provides samples and even downloadable offline versions of the VBA documentation.
Related
This question is a stumper, for experts only.
We are using Visual Studio 6 to develop a complex COM Add-In for Access. When compiled, the Add-In works fine. But, when we use Ctrl-F5 to put the VB6 IDE in debug mode, Access throws a
Run-time error 13: Type mismatch
error when it tries to assign the Access Application.COMAddIns("AddInName").Object reference to an early-bound VBA variable of a type exposed in the AddInName type library.
Further information:
The Access application uses objects created by calls to the Add-In
The Add-In DLL also serves as a type library that is included in Access VBA References
The type Access requests from the Add-In is defined in the AddInName type library
In Access VBA, the failing code looks like this:
Public Function GetAddInRef As AddInName.SomeClass
Dim objSomeClass As AddInName.SomeClass
' .Object is set to a SomeClass instance in IDTExtensibility2_OnConnection
Set objSomeClass = Application.COMAddIns("AddInName").Object ' => Error 13!
Set GetAddInRef = objSomeClass
End Function
If you change the type of objSomeClass to Object, the assignment works. If you set a break on the offending line, you can do things like this in the Immediate window:
? TypeName(objSomeClass)
AddInName.SomeClass
? TypeOf objSomeClass Is AddInName.SomeClass
False
So it is saying that the class name of objSomeClass is "AddInName.SomeClass", but it is not of type AddInName.SomeClass. Madness!
Further, if you put in code that exposes the CLSID for the Access-side reference and the Add-In originated object, they both return the same GUID! So why does VBA complain that the types are different?
Does anyone have any insight into what is happening here? I would be very grateful for any help.
I'm guessing (I am no expert) it's because AddInName.SomeClass is not an object, it is of type AddinName.SomeClass. Drop the .Object off of Application.COMAddIns("AddInName").Object and I think it will work just fine. If you need it as an object for somewhere else in your code, then change your AddInName.SomeClass types to Object and leave the .Object on Application.COMAddIns("AddInName").Object and it should work.
So a colleague of mine stumbled upon the answer: Set Access and VB6 permissions to administrator! I tried it, and Voilà, debugging works.
For each of the following executable files, Right-click, Properties, Configuration, then check Run this program as an administrator:
Office path:
MSACCESS.EXE (or EXCEL.EXE or WINWORD.EXE ...)
C:\Program Files (x86)\Microsoft Visual Studio\VB98\
VB6.EXE
LINK.EXE
Notes:
It probably helps to develop VB6 apps using an administrative login, too.
This makes sense, because VB6 had its start in the Windows 95 era, when users were pretty much the king of their OS instance.
Caveat: this may not be a perfect solution for very complex Access forms with lots of DLL interaction, but it is much better than nothing!
Say I have a project, I have several CFC's in that project. For the sake of the example, I have a debugging function general.cfc and I want to use that function in mandrill.cfc without having to copy and paste the code into the latter cfc. I've googled this until I can google no more and I know I need to post it here.
Anyone care to take me to school?
This is how I would do it
<cfset var objGeneral = createObject("component","general")>
Then if you have a function in general.cfc called getName() you can call it by saying objGeneral.getName()
You should look at the notion of dependency injection, and you should specifically look at how ColdSpring implements it in the context of ColdFusion (or DI/1).
Basically you have an init() argument in Mandrill which would take a General object, and then you set the General object into the variables scope of the Mandrill object, using its methods via variables.general.
That said, this works best on singleton objects. If you need to do this sort of thing on a transient object, I'd just instantiate the General object as needed within your Mandrill code (ie: now Matt Busche is suggesting).
My solution was to have mandrill.cfc extend the general.cfc component:
<cfcomponent extends="general" name="mandrill" ...>
See also CreateObject
I need to implement switch from one window to another in IE. However, element driver doesn't support getWindowHandle function.
I assume it might be just configuration problem or settings, though I don't know how to fix it.
Please, any suggestions.
I'm working with c# - Visual Studio
You haven't said which language bindings you're using, but based on a comment you posted, it looks like you're using C#. The method names are slightly different for each language binding. From this answer:
The object, method, and property names in the .NET language bindings
do not exactly correspond to those in the Java bindings. One of the
principles of the project is that each language binding should "feel
natural" to those comfortable coding in that language.
So you have to do a little translation if you're trying to copy-paste Java code. In this case, you want the combination of the WindowHandles property (to look for the new window handle) and the CurrentWindowHandle property of the driver. You can find full API documentation for the .NET bindings at the project's Google code site.
I am going to make wild guess:
Try to initialize your driver like this:
WebDriver driver = new FirefoxDriver(); //assume you use firefox
The interface WebDriver supports that method. Do not forget to store the handle somewhere ;)
String myWindow = driver.getWindowHandle();
BTW that method should return you actual window If you need all windows you probably should use getWindowHandles() method
If this does not work, please provide more info:
what error exactly are you getting?
How do you initialize WebDriver?
What version of selenium are you using?|
What type of driver are you using?
I have a Access 2003 database that will dynamically load MDB databases as a library reference. The reason for this is this database is a menu front-end for 60+ application databases. Rather than deal with permanently referencing all these databases, the menu front-end will dynamically reference what is needed when the user makes a selection. I was working on moving this database to Access 2010 and creating a custom ribbon. I started using the technique from here to capture the ribbon object in a global variable when the ribbon loads. I then ran into the problem where I could verify the code was running and the global variable was correctly being assigned the ribbon reference but after the database would run through it's startup routine, that global variable would get reset to Nothing.
To verify what was going on, I created a simple database for testing. In this database, I had a module with a global variable:
Public obj as Object
I then had a function like this:
Public Function SetObj()
Set obj = Application
Debug.Print "IsNothing=" & (obj Is Nothing)
References.AddFromFile "Test.mdb"
Debug.Print "IsNothing=" & (obj Is Nothing)
End Function
Obviously, in my code, "Test.mdb" refers to an actual file. If I run this code, Debug.Print gives me "IsNothing=False" for both instances, but after the function finishes and if I wait a couple seconds, Debug.Print will give me "IsNothing=True". If I comment out References.AddFromFile, Debug.Print gives me "IsNothing=False" no matter how long I wait.
It makes sense to me that since Access has to re-compile the VBA code after loading the library that all global variables are reset. I've experimented with moving the global variable into a class, but since I then need a global variable for the class, the class variable then gets reset instead. I tried using a local variable in the function to save the value of the global variable, but it looks like Access waits a couple seconds after the code is finished running to do the re-compile, so that doesn't work either. Does anyone have any other ideas to accomplish this?
I don't really know if this will solve the problem for this kind of reference, but in general, I don't use public variables for this kind of thing, but instead use a STATIC variable inside your function. It would be something like this:
Public Function SetObj() As Object
Static obj As Object
If (obj Is Nothing) Then
Set obj = Application
End If
Set SetObj = obj
End Function
Then you'd just use SetObj as an object for using your application. In a production app, you'd need tear-down code, too, but I've omitted that here.
I doubt this helps, but your code struck me as rather inefficient and incomplete.
I figured out a solution to my problem, and thanks #David-W-Fenton, as your answer gave me the idea. I use your approach in a library database for caching frequently-accessed values that are stored in a table but don't change after the initial startup. Those values aren't lost every time the references change, and that's when the light bulb lit up.
The solution is to put the global variable in a library database. Access looks to be only resetting global variables in the database that the reference is being loaded into - which makes sense after thinking about it. So since the library database isn't the one being re-compiled, it doesn't get it's global (or private or static) variables reset.
What I ended up doing was creating a new module in an existing library database. It has a private variable and two methods - one to set the variable, one to retrieve the variable value. In my menu front-end database, when the ribbon loads and calls my callback function, rather than saving the ribbon object in the front-end database, I pass it to this module for saving. I now no longer lose that ribbon reference whenever new databases are added to the library references on the fly.
I started using LINQ to SQL recently. On my DMBL designer, I open the server explorer and drag a stored proc onto the designer.
I open the properties for the Method in the designer and see that its return type is AutoGenerated. I look at the designer.cs class and it says
the return type is ISingleResult<GetEmloyeeeRecordDataResult>.
Can this be cast to IList<GetEmployeeRecordDataResult>?
I tried doing this and there are no compile time errors. I am trying to understand what a ISingleResult<T> is and how it can be cast to IList<T>.
Use ToList()