/// <summary>
/// Tries to get the DISPID for the requested member name.
/// </summary>
/// <param name="dispatch">An object that implements IDispatch.</param>
/// <param name="name">The name of a member to lookup.</param>
/// <param name="dispId">If the method returns true, this holds the DISPID on output.
/// If the method returns false, this value should be ignored.</param>
/// <returns>True if the member was found and resolved to a DISPID. False otherwise.</returns>
private static bool TryGetDispId(IDispatchInfo dispatch, string name, out int dispId)
{
RequireReference(dispatch, "dispatch");
RequireReference(name, "name");
bool result = false;
// Members names aren't usually culture-aware for IDispatch, so we might as well
// pass the default locale instead of looking up the current thread's LCID each time
// (via CultureInfo.CurrentCulture.LCID).
Guid iidNull = Guid.Empty;
int hr = dispatch.GetDispId(ref iidNull, ref name, 1, LOCALE_SYSTEM_DEFAULT, out dispId);
const int DISP_E_UNKNOWNNAME = unchecked ((int)0x80020006); //From WinError.h
const int DISPID_UNKNOWN = -1; //From OAIdl.idl
if (hr == S_OK)
{
result = true;
}
else if (hr == DISP_E_UNKNOWNNAME && dispId == DISPID_UNKNOWN)
{
// This is the only supported "error" case because it means IDispatch
// is saying it doesn't know the member we asked about.
result = false;
}
else
{
// The other documented result codes are all errors.
Marshal.ThrowExceptionForHR(hr);
}
return(result);
}
private static bool TryGetDispId(IDispatchInfo dispatch, string name, out int dispId)
{
RequireReference(dispatch, "dispatch");
RequireReference(name, "name");
bool result = false;
Guid iidNull = Guid.Empty;
int hr = dispatch.GetDispId(ref iidNull, ref name, 1, LOCALE_SYSTEM_DEFAULT, out dispId);
const int DISP_E_UNKNOWNNAME = unchecked ((int)0x80020006); //From WinError.h
const int DISPID_UNKNOWN = -1; //From OAIdl.idl
if (hr == S_OK)
{
result = true;
}
else if (hr == DISP_E_UNKNOWNNAME && dispId == DISPID_UNKNOWN)
{
result = false;
}
else
{
Marshal.ThrowExceptionForHR(hr);
}
return(result);
}
/// <summary>
/// Gets a Type that can be used with reflection.
/// </summary>
/// <param name="dispatch">An object that implements IDispatch.</param>
/// <param name="throwIfNotFound">Whether an exception should be thrown if a Type can't be obtained.</param>
/// <returns>A .NET Type that can be used with reflection.</returns>
static Type GetType(IDispatchInfo dispatch, bool throwIfNotFound)
{
RequireReference(dispatch, "dispatch");
Type result = null;
int hr = dispatch.GetTypeInfoCount(out int typeInfoCount);
if (hr == SOk && typeInfoCount > 0)
{
// Type info isn't usually culture-aware for IDispatch, so we might as well pass
// the default locale instead of looking up the current thread's LCID each time
// (via CultureInfo.CurrentCulture.LCID).
dispatch.GetTypeInfo(0, LocaleSystemDefault, out result);
}
if (result == null && throwIfNotFound)
{
// If the GetTypeInfoCount called failed, throw an exception for that.
Marshal.ThrowExceptionForHR(hr);
// Otherwise, throw the same exception that Type.GetType would throw.
throw new TypeLoadException();
}
return(result);
}
private static Type GetType(IDispatchInfo dispatch, bool throwIfNotFound)
{
RequireReference(dispatch, "dispatch");
Type result = null;
int typeInfoCount;
int hr = dispatch.GetTypeInfoCount(out typeInfoCount);
if (hr == S_OK && typeInfoCount > 0)
{
dispatch.GetTypeInfo(0, LOCALE_SYSTEM_DEFAULT, out result);
}
if (result == null && throwIfNotFound)
{
// If the GetTypeInfoCount called failed, throw an exception for that.
Marshal.ThrowExceptionForHR(hr);
// Otherwise, throw the same exception that Type.GetType would throw.
throw new TypeLoadException();
}
return(result);
}
