private void MenuItemCallback(object sender, EventArgs e)
        {
            var injectDependencyCaption = "Inject Dependency";

            if (_dte.ActiveDocument == null)
            {
                DialogHelpers.Error("Open a code file first.", injectDependencyCaption);

                return;
            }

            using (var injectDependencyDialog = new InjectDependencyDialog(
                       _fieldNameGenerators,
                       _dependencyNameProviders,
                       _dependencyInjector.GetExpectedClassName(_dte.ActiveDocument)))
            {
                if (injectDependencyDialog.ShowDialog() == DialogResult.OK)
                {
                    var dependencyInjectionData = injectDependencyDialog.GetDependencyInjectionData();

                    if (string.IsNullOrEmpty(dependencyInjectionData.FieldName) ||
                        string.IsNullOrEmpty(dependencyInjectionData.FieldType) ||
                        string.IsNullOrEmpty(dependencyInjectionData.ConstructorParameterName) ||
                        string.IsNullOrEmpty(dependencyInjectionData.ConstructorParameterType))
                    {
                        DialogHelpers.Warning("Field and constructor parameter names and types must be filled.", injectDependencyCaption);

                        return;
                    }

                    var result = _dependencyInjector.Inject(
                        _dte.ActiveDocument,
                        injectDependencyDialog.GetDependencyInjectionData());

                    if (!result.Success)
                    {
                        switch (result.ErrorCode)
                        {
                        case DependencyInjectorErrorCodes.ClassNotFound:
                            DialogHelpers.Warning(
                                "Could not inject dependency because the class was not found in this file.",
                                injectDependencyCaption);
                            break;

                        default:
                            DialogHelpers.Warning("Could not inject dependency.", injectDependencyCaption);
                            break;
                        }
                    }
                }
            }
        }