AutoCAD Map 3D includes a number of controls for use in AutoCAD Map 3D forms, some of which replicate standard Windows user control and some of which are unique to AutoCAD Map 3D. To add AutoCAD Map 3D controls to the Visual Studio Toolbox:
In the Toolbox, right-click and click Choose Items.
In the Chose Toolbox Items dialog box, click Browse.
From the AutoCAD Map 3D Client /bin/ directory, select Autodesk.Map.IM.Forms.dll.