How To Use Late Binding To Invoke Method With ByRef Parameters
May 22, 2009
I have a COM component that I want to call using late-binding from VB.NET (using Primary Interop Assembly - PIA method). My IDL signature for the COM method looks like:
HRESULT Send([in]BSTR bstrRequestData,
[out]VARIANT *pvbstrResponseData,
[out]VARIANT *pvnExtCompCode,
[out,retval]int *pnCompletionCode);
So 2 'ByRef' parameters in VB.NET lingo, and a return value. I attempt to invoke this method like so:
Dim parameters(2) As Object
parameters(0) = "data"
parameters(1) = New Object()
parameters(2) = New Object()
Dim p As New ParameterModifier(3)
[Code] .....
This fails spectactularly with an exception: {"Invalid callee. (Exception from HRESULT: 0x80020010 (DISP_E_BADCALLEE))"}
I assume this means I'm doing something wrong in my parameterMods array. Because if I comment out setting any value of the ParameterMods array to 'True' - it works. It of course doesnt update the parameters that are [out] parameters and so it's not working as intended. Is there something else to consider since the method also has a return value? The MSDN example pretty much does exactly what I am doing, with the exception that example did not have a return value.
I'm currently invoking a function that takes ByRef parameters using Control.Invoke (which I notice specifies the Object parameter array to be ByVal) but the array of parameters I give it isn't updated by the function. Is this possible with VB.Net 2003 or must there be some error in my code?
I started programming in VBA, then graduated to VB6, and I am now using VB.NET 2008 Express.I have read, in the various posts, that I should keep Option Explicit and Option Strict both on, in order that I use correct VB.NET code and not VB6.I am trying to do that but am totally confused with the results of one of my programmes that was running perfectly with Option Strict off, but now advises:Option Strict On disallows late binding. To me it appears that I am using early binding, but to be honest I am not clear on the binding situation. I have checked through a number of google items, and a number of this Forum's items without seeing the light.[code]
I have to work with an API that uses a lot of by-reference parameters. I'm just beginning to use NMock, and I'm having trouble seeing how to make NMock actually modify one of those by-ref parameters to a specific value. Am I missing something, or does it just not do that? Is there a better way, short of wrapping this API?
i have this code:Private Sub frmMain_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
[Code]...
Error 1: Option Strict On disallows late binding.Im using visual basic 2010 express on a gateway laptop thats running Windows 7 OS How do i resolve this error?
I have a listbox and it it I am showing numbers.It should look like this (line by line) 1,2,3,4,5,6,7,8,9,10,11.....but is is showing it like this 1,10,11,...2,20,21...3,30...ow can I make it that it will show it in number order 1,2,3,4,5......
Is it possible to possible to make the following code to produce an error at compile time? (please see the line marked by the comment):
Option Strict On Option Explicit On Module Module1
Private Sub Test(ByRef i As Integer)
i = 999 End Sub
Sub Main()
Dim o As Object = 5 expecting an error message like in C# "A ref or out argument must be an assignable variable"Test(CInt(o))System.Console.Out.WriteLine("Testvalue: {0}", o)End Sub
I create tabpages at runtime each having a flexgrid controls. I need to pass these flexgrids of each tabpage as a parameter to a function byref. This is the code .
I have some code that is transforming the coordinates of a line.I want to keep the original coords and I thought passing the line ByVal would be the best way.The original VB6 code used a temporary variable so that the original coords were not updated.I'm confused as when the X & y coords of 'line' are changed 'MyLine' is also changed. I had assumed only 'line' would change and 'MyLine' would remain unchanged'.
Private Sub TransformSaveLine(ByVal MyLine As LineType) Dim P As Integer Dim line As LineType Dim x As Double
I'm getting a late binding error message on this specific section of code: objsys.Sessions(shrd.ocSess) Any suggestions as to why I'm getting this late binding error and how to fix it? [Code]
So I am taking a stab at converting a large VBA project I'm working into .NET. It's in VBA right now only because of convenience of a database (MS Access). But having stumbled upon VB 2010 Express, I'm seeing what I can do in .NET to make my project even better.To that end, one trick I am doing in the VBA project involves late binding.[code]To provide a simplified example, lets say I have three classes, clsOne, clsTwo, and clsThree. They are themselves similar, and in .NET, I'm actually reducing the code each has due to proper class inheritance. But I need to understand how to move away from late-binding, which I use in the VBA project.Now reading into VB .NET some, I've come across the 'Of' keyword, and this looks like the holy grail that I've been seeking. Please understand that these example is not actual code, and the issue cannot be solved (as far as I know) by fancy inheritance and overloading/overriding.[code]
I have strongly typed code which throws a Late binding Disallowed due to Strict On exception. Is there a way to allow late binding, without turning my stict option to off?
I have a class from where I need to set objects in another form?
Form1: vb.net Function SetMyObject(ByVal frmTarget As Object) frmTarget.PictureBox1 = Form1.PictureBox1 End Function
(Not tested code, just wrote to show what I mean)So that's the late binding one.I should also say that the frmTarget variable isn't static so thats why I can't make something like Form2.PictureBox1 = Form1.PictureBox1
I like to keep Option Strict On, but in some cases I need late binding.
For example I need to read the value of Geometry.Area when Geometry could be either a Square or a Circle.
It is not my object model, and Square and Circle are not derived nor share an interface that implements the Area property, so I need either a huge Select Case for each geometry type and for each property, or I use late binding.
I tried with this and a few similar variants, but I couldn't get it to work:
Geometry.[GetType]().InvokeMember("Area", Reflection.BindingFlags.GetProperty Or Reflection.BindingFlags.Public Or Reflection.BindingFlags.Instance, Nothing, Geometry, Nothing)
I am trying to get some code to compile after switching Option Strict On. However I am using some Interop with VB6 and passing in a form object ByRef so Form.Caption fails and I can't convert it to type Form because a VB.NET Form doesn't have a caption property.
How can I can get the following to compile with Option Strict ON:
Public Sub EditFormLegacy(ByRef objForm As Object) objForm.Caption = objForm.Caption + " Edited" End Sub
Is there any way to switch option strict off for specific methods?
I have a function where i am opening up an excel doc and spitting some data out to it. I had this working but then needed to make it so that it would work with older versions of excel as well as 2010.
It was suggested on here that i use late binding instead of including the office interop and allow the system select the appropriate version of interop to use.
I'm trying out MVC Scaffolding in a VB.NET MVC3 project and running into an issue with late binding with Option Strict set on (and I want it on).
This works in C#:
public ActionResult Create() { ViewBag.PossibleTeams = context.Teams;
[code].....
causes the compiler error Option Strict On disallows late binding. I took a look at the documentation here: [URL] but it wasn't very helpful.
I notice that a new empty application in C# uses the ViewBag in the HomeController but the VB.NET version uses ViewData, so maybe this is a VB.NET limitation.
We are working with an existing native application (most likely written in VB) that loads assemblies and calls methods with "Late Binding." We do NOT have access to its source code. We want to implement this interface in C#, and have the native application call our C# assembly. Is this anything we have to do beyond matching the method names and method signatures to make it work?