How to register C or VB. Net DLLs for Access VBA, Excel VBA, or VB6 applications. How to register a C or VB. Net DLLAfter you created a C or VB. Net DLL, you need to register it on a target machine. You can use Microsofts. Reg. Asm. exe utility. Regasm. exe is an Assembly Registration tool used to read the metadata within an assembly. It also adds the necessary entries to the. COM client VB6 applications, or Microsoft VBA, eg. Access, Excel, etc to create. NET Framework classes. Once a class is registered using Regasm. Manual_CFD33/index_archivos/image015.png' alt='Codebase Regasm.Exe' title='Codebase Regasm.Exe' />regasmcodebase COM. Daten/Images/2/Image_2078_5.jpg' alt='Codebase Regasm.Exe' title='Codebase Regasm.Exe' />The next thing to do is registering the class library for COM interop from Project properties Build. This can be done manually with regasm. COM client can use. COM component. Reg. Asm. exe file comes with. Net framework installation and can be found in Microsoft. NET framework folder. There are different versions of Reg. Asm. exe. Net framework 2. Reg. Asm. exe which locates in the. Net framework V2. C WINNTMicrosoft. NETFrameworkv. 2. Reg. Asm. exe. C WindowsMicrosoft. NETFrameworkv. 2. Reg. Asm. exe. Net framework 4. Reg. Asm. exe which locates in the. Net framework V4. C WINNTMicrosoft. NETFrameworkv. 4. Reg. Asm. exe. C WindowsMicrosoft. NETFrameworkv. 4. Reg. Asm. exe. Reg. Asm. exe and DLL mapping. If you receive this error Reg. Asm error RA0. 00. Failed to load c winntsystem. Your. DLLFile. dll because it is not a valid. NET assembly. you are probably trying to use a. Net framework 2 Reg. Asm. exe to register a DLL that is created by using. Net framework 4. Net Framework. Reg. Asm. exe default installation path. Your DLL should be created by. Net framework 2. 03. C WINNTMicrosoft. NETFrameworkv. 2. Reg. Asm. exe. Net framework 2. Net framework 4. 0. C WINNTMicrosoft. NETFrameworkv. 4. Reg. Asm. exe. Net framework 4. So when registering DLL assemblies that are created by. Net framework 4, we must NOT use Reg. Asm. exe that comes in. Net framework 2. 03. How to run Reg. Asm. To execute Reg. Asm. Reg. Asm. exe is located and run it otherwise you will get Reg. Asm is not recognized as internal or external command, operable program or batch file error message. Assume I have already added my DLL to folder C WINNTsystem. I can run the following command. C WINNTMicrosoft. NETFrameworkv. 4. Reg. Asm. exe Simple. Calc. dll codebase. Note that you dont need to specify C WINNTsystem. Reg. Asm. exe will automatically look up Simple. Calc. dll in C WINNTsystem. The codebase parameter is an optional parameter that adds information about the DLL to the Windows registry which specifies the assemblys path on the disk. Regasm can also be used to unregister a DLL. If the DLL you got does not have type library file associated with it, one can be generated by using the Regasm utility and the tlb option. C WINNTMicrosoft. NETFrameworkv. 4. Reg. Asm. exe Simple. Calc. dll tlb Simple. Calc. tlb. Note that, to export a type library from the DLL, you need administrator privileges on the computer, or you will receive this type of error Reg. Asm error RA0. 00. An error occurred while saving the exported type library Access is denied. Note that you can create environmental variables for the. Net framework Reg. Asm. exe to simplify DLL registration. Happy Registering Copyright Geeks. Engine. com. Other Recent Articles from the MS Access category. How to create C or VB. Net DLLs for VB or VBA in Access or Excel. Create a DLL by CSharp or VB. Net for VBAI was updating an application I created in Access VBA and came across a scenario that I needed to. DLL. I used to use VB Visual Basic 5 and 6 to create. DLLs many years ago. The best way nowadays is to use C or VB. Net to create the DLL. Creating a DLL in C or VB. Net is not that hard as long as you have object oriented programming experience or knowledge. Embird Manual there. After creating the DLL, I tried to reference it from Access VBA editor but kept getting the message. Cant add a reference to the specified file. After some research on this issue, I learned some new tricks about. DLL for Access or Excel or any Microsoft Office applications or VB6 applications, 2 how to correctly register. C or VB. Net DLL, and 3 how to correctly reference the DLL within Access VBA or Excel VBA. In this article, Im going to show you how to correctly create a C or VB. Net DLL in Visual Studio and use it inside MS Access, Excel VBA, or VB6 applications. Hope the tips can save you a couple of hours or days of headaches. Create a new C or VB. Net project and select Class Library as the template type. Save the project and solution as Simple. Calc. Below I created a simple calculation class for testing. This class has two variable members and one Add method. The method adds two integer numbers and returns the result. System. Collections. Free Download Directsound Driver For Windows Xp. Generic. using System. Linq. using System. Text. namespace Simple. Calc. public class. Calc. privateint number. One 0. privateint number. Two 0. publicvoid Set. Number. Oneint number. One number. publicvoid Set. Number. Twoint number. Two number. Add two integerspublicint Add. One number. Two. Configure project properties to make it COM visible. Open project properties dialogue window. Go to menu Project Simple. Calc Properties. When the project properties window is opened, click Application tab, and then click Assembly Information button. On the Assembly Information window, check Make assembly COM Visible. Applications created in VB or VBA are COM based applications. So the class library you. C or VB. Net must be created as a COM visible assembly. This allows COM based. Register for COM Interop. In addition to making the DLL COM visible, we also need to register the assembly as a. COM component in the Windows registry. There are a few ways to do it based on your circumstances. For a development machine, we can check Register for COM Interop setting in Visual Studio. On the project. properties window, click Build tab. Then check Register for COM Interop Based on your version of Visual Studio, it could be. This makes Visual Studio do two things automatically when the project is compiled. First, it will generate a. Second, it will register class information for the COM component. Windows registry. The Register for COM interop property specifies whether your application will expose a COM object to client applications. COM object transparently. Here is what is registered in Windows registry for the compiled assembly so that COM clients can use the. NET class transparently. Note that the path to the DLL is stored in Code. Base entry. To register the assembly on other computers such as production machines, you can register the assembly by. Reg. Asm. exe. See this article for details. Compile the project. Build the solution. Then go to bin folder. Depends on whether your build is a Debug or Release build. DLL and. tlb type library file in either Debug or Release folder under the bin directory. In our case, its D CSharpSimple. CalcSimple. CalcbinRelease. Copy the type library file to Windows system folder. Windows system folder C WINNTsystem. DLLs and type libraries so we copy type library Simple. Calc. tlb to it. 6. Write A Program To Reverse A String In Vb.Net more. Reference the type library from Access VBA editor. First, create a new Access database and open Visual Basic code editor. In the menu cross the top, click. Tools References. When the References window is opened, click the button Browse. Then browse to folder C WINNTsystem. Simple. Calc. tlb and click Open. After done, Simple. Calc will appear in your reference list and you need to move down in the list to find and check it. Then click OK. to close the Reference window. You may remember in the registry screenshot above, there is a DLL path value in Code. Base entry. VBA will use this registry information. DLL to call. In our case, its D CSharpSimple. CalcSimple. CalcbinReleaseSimple. Calc. dll. 7. Use the DLL in your VBA code. To use the variables and methods in the C DLL, we need to call the DLL inside VBA. Add a button to the Access form and then add a click event to it. In the click event we call a function called test which is created within a VBA module. Below is a sample VBA to call Simple. Calc. dll. test function invokes the. Net DLL by creating a new object from Calc class and then call its methods. Public. Function test. Dim lng. Result As. Long. Dim obj. Calc As Simple. Calc. Calc. Set obj. Calc New Simple. Calc. Calc. obj. Calc. Set. Number. One 3. Calc. Set. Number. Two 6. Result obj. Calc. Add. If we debug and step through the test function, we will see the result is 9 as its calculated inside the C DLL and returned to VBA. You can see the result value either in Immediate window or by moving mouse over the lng. Result variable. In this article, we have gone through the steps to create a. Net C DLL and then use it inside Access VBA. It brings the power of. Net. into Microsoft Office applications. The limitation in this article is that Visual Studio registered our DLL and type library automatically for our development machine only. We havent covered how to deploy the DLL to a production machine. In this case, check out this article about how to use Regasm. Assembly Registration Tool to register DLL on a target machine or production computer. Note that you can also create a setup package for your application and add regasm. Happy Coding Copyright Geeks. Engine. com. Other Recent Articles from the MS Access category.