OpenTween.TweenMain.FavoriteChange C# (CSharp) Method

        private async Task FavoriteChange(bool FavAdd, bool multiFavoriteChangeDialogEnable = true)
        {
            TabModel tab;
            if (!this._statuses.Tabs.TryGetValue(this._curTab.Text, out tab))
                return;

            //trueでFavAdd,falseでFavRemove
            if (tab.TabType == MyCommon.TabUsageType.DirectMessage || _curList.SelectedIndices.Count == 0
                || !this.ExistCurrentPost) return;

            if (this._curList.SelectedIndices.Count > 1)
            {
                if (FavAdd)
                {
                    // 複数ツイートの一括ふぁぼは禁止
                    // https://support.twitter.com/articles/76915#favoriting
                    MessageBox.Show(string.Format(Properties.Resources.FavoriteLimitCountText, 1));
                    _DoFavRetweetFlags = false;
                    return;
                }
                else
                {
                    if (multiFavoriteChangeDialogEnable)
                    {
                        var confirm = MessageBox.Show(Properties.Resources.FavRemoveToolStripMenuItem_ClickText1,
                            Properties.Resources.FavRemoveToolStripMenuItem_ClickText2,
                            MessageBoxButtons.OKCancel, MessageBoxIcon.Question);

                        if (confirm == DialogResult.Cancel)
                            return;
                    }
                }
            }

            if (FavAdd)
            {
                var selectedPost = this.GetCurTabPost(_curList.SelectedIndices[0]);
                if (selectedPost.IsFav)
                {
                    this.StatusLabel.Text = Properties.Resources.FavAddToolStripMenuItem_ClickText4;
                    return;
                }

                await this.FavAddAsync(selectedPost.StatusId, tab);
            }
            else
            {
                var selectedPosts = this._curList.SelectedIndices.Cast<int>()
                    .Select(x => this.GetCurTabPost(x))
                    .Where(x => x.IsFav);

                var statusIds = selectedPosts.Select(x => x.StatusId).ToArray();
                if (statusIds.Length == 0)
                {
                    this.StatusLabel.Text = Properties.Resources.FavRemoveToolStripMenuItem_ClickText4;
                    return;
                }

                await this.FavRemoveAsync(statusIds, tab);
            }
        }