Setting an Enum property on a .NET object

问题

Moving on from this question: Setting a "nullable" property on a .NET object

Thanks to Olivier for his help so far. I am now using this import for the .NET type library: https://github.com/DelphiWorlds/MiscStuff/blob/master/Test/mscorlib_TLB.pas which is based on v4 of the CLR, as opposed to the antiquated version I was using.

..and I now have this code:

procedure TDotNetObject.SetEnumProperty(const APropertyName: string; const AValue: OleVariant; const ATypeName: string; const AIndex: Integer = -1);
var
  LRes: HRESULT;
  LEnumType, LPropertyType: _Type;
  LInvokeFlags: TOleEnum;
  LArgs: PSafeArray;
  LConvertedValue: OleVariant;
  LPropertyInfo: _PropertyInfo;
  LIndex: PSafeArray;
  LName: WideString;
  LResHex: string;
begin
  LPropertyType := nil;
  LRes := FType.GetProperty(APropertyName, BindingFlags_Instance or BindingFlags_Public or BindingFlags_NonPublic, LPropertyInfo);
  if Succeeded(LRes) then
  begin
    if ATypeName.IsEmpty then
      LPropertyInfo.GetType(LPropertyType)
    else
      LPropertyType := MTDataClr.GetType(ATypeName); // This is a workaround since for obtaining the underlying type
  end;
  if LPropertyType <> nil then
  begin
    // Convert the value to the correct type
    LEnumType := MTDataClr.GetCoreType('System.Enum');
    LInvokeFlags := BindingFlags_InvokeMethod or BindingFlags_Public or BindingFlags_Static;
    LArgs := VariantToPSafeArray(VarArrayOf([LPropertyType, AValue]));
    if Succeeded(LEnumType.InvokeMember_2('ToObject', LInvokeFlags, nil, Null, LArgs, nil, LConvertedValue)) then
    begin
      if AIndex >= 0 then
        LIndex := VariantToPSafeArray(VarArrayOf([AIndex]))
      else
        LIndex := nil;
      LRes := LPropertyInfo.SetValue(FTarget, LConvertedValue, LIndex);
      if not Succeeded(LRes) then
      begin
        LResHex := IntToHex(LRes);
        Sleep(0);
      end;
    end;
  end;
end;

Everything works up until SetValue. LResHex is '80070057' which apparently equates to ERROR_INVALID_PARAMETER.

Any clues as to where I have gone wrong?

来源：https://stackoverflow.com/questions/61514990/setting-an-enum-property-on-a-net-object

标签

.net

Delphi

com-interop