Article ID: 316478 - View products that this article applies to.
This article was previously published under Q316478
When you set a public object variable of a Microsoft Component Object Model (COM) component in Microsoft Visual Basic .NET or in Microsoft Visual Basic 2005, you may receive the following error message:
An unhandled exception of type 'System.Runtime.InteropServices.COMException' occurred in microsoft.visualbasic.dll
Additional information: Object variable or With block variable not set
This behavior can occur if all the following conditions are true:
The BindingFlags enumeration is used to specify the flags that control binding and the way in which the search for members and types is conducted by reflection.
To work around this problem, use one of the following methods.
Use early binding in Visual Basic .NET or in Visual Basic 2005Use early binding in the Visual Basic .NET or Visual Basic 2005 client application. This is the easiest solution because you do not have to rebuild the COM component. To use early binding in Visual Basic .NET or in Visual Basic 2005, define the object variable by using the type name from the interop assembly that is generated when you set the reference to the component. Do not define it by using the Object type.
When you use the Visual Basic .NET or Visual Basic 2005 code example that is in the "Steps to reproduce the problem" section, use the following code example to define the object variable.
Do not use the following code example:
Define a public property procedure in the COM componentModify the Microsoft Visual Basic 6.0 COM component to use a public property procedure to set and to return the object. Do this instead of using a global Object variable. This solution is more difficult to implement because you must modify the original Visual Basic 6.0 component. If you do this, you may have to break the binary compatibility of the component.
When you use the Visual Basic 6.0 code example that is in the "Steps to reproduce the problem" section, use the following code example to define a public property procedure within the Class1 class to set and to retrieve the object variable.
Microsoft has confirmed that this is a bug in the Microsoft products that are listed in the "Applies to" section.
Steps to reproduce the problem
Create an ActiveX DLL project in Visual Basic 6.0
Create the Visual Basic .NET or Visual Basic 2005 application
Article ID: 316478 - Last Review: May 18, 2007 - Revision: 4.3