Ok, I have a dotnet dll that I can now access via com (thanks to Rick Strahl's article) in VFP like so:

oP = CREATEOBJECT("a.CachStandard.API.oneClass","","")
public lnport  && ignore public declaration etc - only for testing in command window
lnport = 5000  && an example port
llResult = op.connect(lnport) && returns a valid connection 
*--oP now exists and I can view it in the object browser and see interfaces, methods, props, etc.

I can view the interfaces and members like so:

otlb=otli.TypeLibInfoFromFile("a.CachStandard.API.oneClass.tlb")
FOR each oCoClass in otlb.CoClasses
   ?"  ",oCoClass.name
   *now each interface associated with this CoClass
   for each oInterface in oCoClass.Interfaces
      ?"     ",oInterface.name
   endfor
endfor
?
?"Interfaces"
FOR each oInterface in otlb.Interfaces
   ?"  ",oInterface.name
ENDFOR 
?
?"Interface Members for 1st interface"
FOR each oMember IN otlb.Interfaces(1).Members
   ?"  ", oMember.name
   FOR each oParm in oMember.Parameters
      ?"             ",oParm.name
   ENDFOR
ENDFOR

So I know it exists and is accessible from vfp. Now I need to pass information to one of its methods but the parameter is an object which contains many props and collections.

A sesssion class is created which looks like this in c#:

	public class CACHSessionClass
	{
		bool				_Connected;
		string				_IP;
		int				_Port;
		Guid				_aCallID;
		aClass			  	_aRCalls;
		aScriptClass		        _aScript;
		aLogClassCollection	        _aLog;
		aRecommendationClass	        _aRecom;
		aImageClassCollection	        _aImages;
		aStatusEnum		        _aStatus;
	        string				_aTypeCode;
then:

Now the problem: some of the members of the above CACHSessionClass are classes or collections. For example, here is aClass:

  [Serializable]
   public class aClass
    {
        public aClass();

        public aClass(int PSAP, int aPosition, DateTime aCallDateTime);

        public aClass(string aName, string aTeleNumber, double aLatitude, string aLocation,
             );

        public aClassCollection AliFields { get; set; }
        public int aPosition { get; set; }
        public Guid aCallID { get; set; }
        public string aTeleNumber { get; set; }
        public DateTime aCallDateTime { get; set; }
        public string aLocation { get; set; }
        public double aAltitude { get; set; }
        public string aName { get; set; }
        public int PSAP { get; set; }
        public bool IsEqual(aClass ANIALI);
    }

and in turn, the aClassCollection in the above is a collection:

    [Serializable]
    public class aClassCollection : CollectionBase
    {
        public aClassCollection();

        public aField this[int index] { get; set; }

        public int Add(aField value);
        public void Clear();
        public bool Contains(aField value);
        public aField FindByFieldName(string FieldName);
        public int IndexOf(aField obj);
        public void Insert(int index, aField value);
        public void Remove(aField obj);
        public void RemoveAt(int index);
    }

and in turn, afield in aClassCollection above is like so:

    [Serializable]
    public class aField
    {
        public aField();
        public aField(string Name, string Value);

        public string Name { get; set; }
        public string Value { get; set; }
    }

and on and on and on...

A new aClass is created like so in c#:

		private void CreateSampleaClass()
		{
			aClass call0 = new aClass();
			call0.ID = Guid.NewGuid().ToString();
			call0.CACHCallID = Guid.Empty;
			call0.aCallDateTime = DateTime.Now;
			call0.aFields = new aClassCollection();		
			call0.aName= "A";
			call0.aTeleNumber= "23465723463";
			call0.aLocation= "location";
                 etc.......

Can anyone help me get started? I think I need to create a session probably like so:

PUBLIC oaClass
oaClass = NEWOBJECT('aClass',"a.CachStandard.API.oneClass.tlb")
DEFINE CLASS aClass AS session OLEPUBLIC

   IMPLEMENTS aClass IN "a.CachStandard.API.oneClass.tlb"  

ENDDEFINE

But that returns the error: "Class cannot be instantiated because Member 'aClass_get_ToString' does not exist.

aclass does contain a ToString property

Or am I on the wrong track?


UPDATE: This seems to be working for setting the props (that are simple strings or int or guids):

Public loAPI as a.CachStandard.API.oneClass.aClass
loAPI = CREATEOBJECT("a.CachStandard.API.oneClass.aClass","","")
loAPI.ID = '00000000-0000-0000-0000-000000000000'
loAPI.aTeleNumber = '1234567890'
loAPI.alocation = '100 N Main St;HP'

But I still need to set objects and collections and pass them...