Excel-DNA - Range processing via the C API

RangeConvertCAPI.dna

<DnaLibrary Name="RangeConvert using C API" Language="C#" RuntimeVersion="v4.0">
<Reference Name="System.Windows.Forms" />
<![CDATA[
    
    using System;
    using System.Windows.Forms;
    using ExcelDna.Integration;
     
    public static class TestRangeMacros
    {
        [ExcelCommand(MenuName="Test Range Macros - C API", MenuText="Double the Range")]
        public static void RangeDoubleCAPI()
        {
            ExcelReference inRange;
            ExcelReference outRange;
            object[,] inValues;
            object[,] outValues;
            
            try
            {
                inRange = (ExcelReference)XlCall.Excel(XlCall.xlfInput, "Range to read: ", 8 /*type_num = 8 : Range  */, "Doubling function");
                outRange = (ExcelReference)XlCall.Excel(XlCall.xlfInput, "Range to write: ", 8 /*type_num = 8 : Range  */, "Doubling function");

                inValues = (object[,])inRange.GetValue();
                outValues = new object[inValues.GetLength(0), inValues.GetLength(1)];
                
                for (int i = 0; i < inValues.GetLength(0); i++)
                {
                    for (int j = 0; j < inValues.GetLength(1); j++)
                    {
                        if (inValues[i,j] is double)
                            outValues[i,j] = (double)inValues[i,j] * 2.0;
                        else
                            outValues[i,j] = "!ERROR";
                    }
                }
                outRange.SetValue(outValues);
            }
            catch (Exception e)
            {
                    MessageBox.Show(e.ToString());
            }
        }
    } 
]]>
</DnaLibrary>