private ComTypeInfo GetTypeInfo()
{
using (ComAdapter.tracer.TraceMethod())
{
if (this.info == null)
{
this.info = ComTypeInfo.GetDispatchTypeInfo(this.comObject);
}
return(this.info);
}
}
/// <summary>
/// Try to create an enumerator for a COM object.
/// </summary>
/// <returns>
/// A 'ComEnumerator' instance, or null if we cannot create an enumerator for the COM object.
/// </returns>
internal static ComEnumerator Create(object comObject)
{
if (comObject == null || !comObject.GetType().IsCOMObject)
{
return(null);
}
// The passed-in COM object could already be a IEnumVARIANT interface.
// e.g. user call '_NewEnum()' on a COM collection interface.
var enumVariant = comObject as COM.IEnumVARIANT;
if (enumVariant != null)
{
return(new ComEnumerator(enumVariant));
}
// The passed-in COM object could be a collection.
var enumerable = comObject as IEnumerable;
var target = comObject as IDispatch;
if (enumerable != null && target != null)
{
try
{
var comTypeInfo = ComTypeInfo.GetDispatchTypeInfo(comObject);
if (comTypeInfo != null && comTypeInfo.NewEnumInvokeKind.HasValue)
{
// The COM object is a collection and also a IDispatch interface, so we try to get a
// IEnumVARIANT interface out of it by invoking its '_NewEnum (DispId: -4)' function.
var result = ComInvoker.Invoke(target, ComTypeInfo.DISPID_NEWENUM,
args: Utils.EmptyArray <object>(), byRef: null,
invokeKind: comTypeInfo.NewEnumInvokeKind.Value);
enumVariant = result as COM.IEnumVARIANT;
if (enumVariant != null)
{
return(new ComEnumerator(enumVariant));
}
}
}
catch (Exception)
{
// Ignore exceptions. In case of exception, no enumerator can be created
// for the passed-in COM object, and we will return null eventually.
}
}
return(null);
}
