Using AutoCAD DLLs in Visual Studio with .NET

Integrating AutoCAD with .NET technology allows developers to create custom applications to automate and enhance workflows in AutoCAD. To achieve this, specific DLL files must be imported into Visual Studio to interact with the AutoCAD API. This article provides a step-by-step guide on how to set up your development environment.

Essential DLLs for AutoCAD API

To develop an AutoCAD application using .NET (C# or VB.NET), you need to add references to the following essential DLL files:

• AcMgd.dll – Provides classes to interact with the AutoCAD application and its user interface.
• AcDbMgd.dll – Contains classes for manipulating drawing objects stored in a DWG file.
• AcCoreMgd.dll – Includes classes for advanced functionality such as the AutoCAD editor, printing, and custom commands.

These DLL files are located in the AutoCAD installation directory and are necessary for developing plugins or automating tasks.

 

Adding AutoCAD DLLs in Visual Studio

Step 1: Open Visual Studio and Create a Project

1. Open Visual Studio.
2. Create a new project, selecting Class Library (.NET Framework) to develop an AutoCAD plugin.

Step 2: Add References to AutoCAD DLLs

1. Open Solution Explorer in Visual Studio.
2. Right-click on References and select Add Reference.
3. In the dialog box, go to the Browse tab.
4. Navigate to the AutoCAD installation folder, typically located at:
   C:\Program Files\Autodesk\AutoCAD 20XX\
5. Select AcMgd.dll, AcDbMgd.dll, and AcCoreMgd.dll, then click OK.

Step 3: Configure Reference Properties

After adding the DLLs, you need to modify an important property to avoid runtime errors:

1. In Solution Explorer, expand the References node.
2. Select AcMgd.dll, AcDbMgd.dll, and AcCoreMgd.dll.
3. In the Properties window, set Copy Local to False.

This prevents Visual Studio from copying the DLLs to the build directory and ensures that your application loads the files directly from AutoCAD.

Create a Simple AutoCAD Command with .NET

Once the DLLs are added, you can create a custom AutoCAD command. Here’s a simple example in C#:

 using Autodesk.AutoCAD.ApplicationServices;
using Autodesk.AutoCAD.Runtime;
using Autodesk.AutoCAD.EditorInput;

public class MyCommands
{
    [CommandMethod("HelloAutoCAD")]
    public void HelloAutoCAD()
    {
        Editor ed = Application.DocumentManager.MdiActiveDocument.Editor;
        ed.WriteMessage("\nHello AutoCAD, your .NET API is successfully configured!");
    }
}

Load and Run the Application in AutoCAD

Step 1: Build the Project

1. In Visual Studio, click Build > Build Solution.
2. A .dll file will be created in the bin\Debug or bin\Release folder.

Step 2: Load the DLL in AutoCAD

1. Open AutoCAD.
2. In the command console, type: NETLOAD
3. Select the compiled .dll file.
4. Type the following command in AutoCAD: HelloAutoCAD
   
5. You should see the message "Hello AutoCAD, your .NET API is successfully configured!" in the console.

 

Conclusion

The AutoCAD .NET API allows developers to customize AutoCAD and automate complex tasks. By correctly adding the AcMgd.dll, AcDbMgd.dll, and AcCoreMgd.dll libraries in Visual Studio, you can start writing AutoCAD plugins and scripts. Follow the steps outlined above to configure your environment and execute your first custom AutoCAD command.

This is the first step. Stay tuned for the upcoming articles!
The Master.