Creating COM components in .NET

COM is a platform-independent, distributed, object-oriented system for creating binary software components that can interact. COM is the foundation technology for Microsoft's OLE (compound documents) and ActiveX (Internet-enabled components) technologies.

Step 1: Create Class Library project. Add Interface and call in your class.

[Guid("321A78B5-53F6-499A-9333-1A18A1A87F1B")]
[InterfaceType(ComInterfaceType.InterfaceIsIDispatch)]
[ComVisible(true)]
public interface IAmazonService
{
}
[Guid("29C0007F-ED96-4141-986C-A50DA1AC3CAD")]
[ClassInterface(ClassInterfaceType.None)]
[ComVisible(true)]
public class AmazonOrderService : IAmazonService
{
}

You must be defining all the property and Methods you need to create are public.

[Guid("321A78B5-53F6-499A-9333-1A18A1A87F1B")]
[InterfaceType(ComInterfaceType.InterfaceIsIDispatch)]
[ComVisible(true)]
public interface IAmazonService
{
[DispId(1)]
string Serviceurl { get; set; }
[DispId(2)]
string Signaturemethod { get; set; }
[DispId(3)]
string Signatureversion { get; set; }
[DispId(4)]
string ApplicationName { get; set; }
[DispId(5)]
string Applicationversion { get; set; }
[DispId(6)]
string Awsaccesskeyid { get; set; }
[DispId(7)]
string Awssecretaccesskey { get; set; }
[DispId(8)]
string Sellerid { get; set; }
[DispId(9)]
string Marketplaceid { get; set; }
[DispId(10)]
string Createdafter { get; set; }
[DispId(11)]
string Createdbefore { get; set; }
[DispId(12)]
string Lastupdatedafter { get; set; }
[DispId(13)]
string Lastupdatedbefore { get; set; }
[DispId(14)]
string Issetorderstatus { get; set; }
[DispId(15)]
string Separatedvalues { get; set; }
[DispId(16)]
string AmazonOrderId { get; set; }
[DispId(17)]
object GetListOrders();
[DispId(18)]
object GetListOrderItems();
}

[Guid("29C0007F-ED96-4141-986C-A50DA1AC3CAD")]
[ClassInterface(ClassInterfaceType.None)]
[ComVisible(true)]

public class AmazonOrderService : IAmazonService
{
MarketplaceWebServiceOrdersConfig mwsOrderConfig = new MarketplaceWebServiceOrdersConfig();
MarketplaceWebServiceOrdersClient mwsOrderClient;
ListOrdersRequest request;
ListOrderItemsRequest orderitemrequst;
IDictionary<String, String> parameter;
private string[] mwsMarketplaceIdList;
private string _serviceurl;
private string _signaturemethod;
private string _signatureversion;
private string _applicationName;
private string _applicationversion;
private string _awsaccesskeyid;
private string _awssecretaccesskey;
private string _action;
private string _sellerid;
private string _createdafter;
private string _createdbefore;
private string _lastupdatedafter;
private string _lastupdatedbefore;
private string _issetorderstatus;
/// <summary>
/// If multipal then pass string with separated values
/// </summary>
private string _marketplaceid;
private string _separatedvalues;
private string _amazonorderid;
public string Serviceurl
{
get { return _serviceurl; }
set { _serviceurl = value; }
}
public string Signaturemethod
{
get { return _signaturemethod; }
set { _signaturemethod = value; }
}
public string Signatureversion
{
get { return _signatureversion; }
set { _signatureversion = value; }
}
public string ApplicationName
{
get { return _applicationName; }
set { _applicationName = value; }
}
public string Applicationversion
{
get { return _applicationversion; }
set { _applicationversion = value; }
}
public string Awsaccesskeyid
{
get { return _awsaccesskeyid; }
set { _awsaccesskeyid = value; }
}

public string Awssecretaccesskey

{

get { return _awssecretaccesskey; }

set { _awssecretaccesskey = value; }

}
public string Action
{
get { return _action; }
set { _action = value; }
}
public string Sellerid
{
get { return _sellerid; }
set { _sellerid = value; }
}
public string Createdafter
{
get { return _createdafter; }
set { _createdafter = value; }
}
public string Createdbefore
{
get { return _createdbefore; }
set { _createdbefore = value; }
}
public string Lastupdatedafter
{
get { return _lastupdatedafter; }
set { _lastupdatedafter = value; }
}
public string Lastupdatedbefore
{
get { return _lastupdatedbefore; }
set { _lastupdatedbefore = value; }
}
public string Issetorderstatus
{
get { return _issetorderstatus; }
set { _issetorderstatus = value; }
}
public string Marketplaceid
{
get { return _marketplaceid; }
set { _marketplaceid = value; }
}
public string Separatedvalues
{
get { return _separatedvalues; }
set { _separatedvalues = value; }
}
public string AmazonOrderId
{
get { return _amazonorderid; }
set { _amazonorderid = value; }
}
public object GetListOrders()
{
//Your code.
}
public object GetListOrderItems()
{
//Your code.
}
}

For more Details download the Code.

Reference http://msdn.microsoft.com/en-us/library/ee663262%28v=VS.85%29.aspx