using SolidWorks.Interop.sldworks;

using SolidWorks.Interop.swconst;

using System.Runtime.InteropServices;

using System;

using System.Diagnostics;

namespace UpdateBoxCSharp.csproj

{

    public partial class SolidWorksMacro

    {

        public void ProcessAssyBox(SldWorks swApp, AssemblyDoc swAssy)

        {

            object box = null;

            double[] boxArray = new double[6];

            box = (object)swAssy.GetBox((int)swBoundingBoxOptions_e.swBoundingBoxIncludeRefPlanes);

            boxArray = (double[])box;

            Debug.Print("  Min = (" + boxArray[0] * 1000.0 + ", " + boxArray[1] * 1000.0 + ", " + boxArray[2] * 1000.0 + ") mm");

            Debug.Print("  Max = (" + boxArray[3] * 1000.0 + ", " + boxArray[4] * 1000.0 + ", " + boxArray[5] * 1000.0 + ") mm");

        }

        public void Main()

        {

            ModelDoc2 swModel;

            AssemblyDoc swAssy;

            ModelDocExtension swModelDocExt;

            Dimension swDimension;

            string fileName;

            int errors = 0;

            int warnings = 0;

            bool status;

            fileName = "C:\\\\Program Files\\\\SOLIDWORKS Corp\\\\SOLIDWORKS\\\\samples\\\\tutorial\\\\api\\\\key pad_1.sldasm";

            swModel = (ModelDoc2)swApp.OpenDoc6(fileName, (int)swDocumentTypes_e.swDocASSEMBLY, (int)swOpenDocOptions_e.swOpenDocOptions_Silent, "", ref errors, ref warnings);

            swAssy = (AssemblyDoc)swModel;

            swModelDocExt = (ModelDocExtension)swModel.Extension;

            // Print the two diagonal corner points

            // of the bounding box before modifying the

            // assembly

            Debug.Print("Before:");

            ProcessAssyBox(swApp, swAssy);

            // Change a dimension of one of the assembly components

            status = swModelDocExt.SelectByID2("Sketch1@Pad_1-1@key pad_1", "SKETCH", 0, 0, 0, false, 0, null, 0);

            swModel.EditSketch();

            swModel.ClearSelection2(true);

            status = swModelDocExt.SelectByID2("D1@Sketch1@Pad_1-1@key pad_1", "DIMENSION", 0.00306153201295202, 0.0373842545521677, -0.0323079625553351, false, 0, null, 0);

            swModel.ClearSelection2(true);

            swDimension = (Dimension)swModel.Parameter("D1@Sketch1@pad_1.Part");      

  errors = (int)swDimension.SetSystemValue3(0.04, (int)swSetValueInConfiguration_e.swSetValue_InThisConfiguration, null);

            swModel.ClearSelection2(true);

            // Update the bounding box

            swAssy.UpdateBox();

            // Print the two diagonal corner points of the

            // bounding box after modifying the assembly

            Debug.Print("After:");

            ProcessAssyBox(swApp, swAssy);

        }

        ///

        public SldWorks swApp;

    } }

Errors: