OpenTween.TweenMain.DoTabSearch C# (CSharp) Method

        internal void DoTabSearch(string searchWord, bool caseSensitive, bool useRegex, SEARCHTYPE searchType)
        {
            var tab = this._statuses.Tabs[this._curTab.Text];

            if (tab.AllCount == 0)
            {
                MessageBox.Show(Properties.Resources.DoTabSearchText2, Properties.Resources.DoTabSearchText3, MessageBoxButtons.OK, MessageBoxIcon.Information);
                return;
            }

            var selectedIndex = this._curList.SelectedIndices.Count != 0 ? this._curList.SelectedIndices[0] : -1;

            int startIndex;
            switch (searchType)
            {
                case SEARCHTYPE.NextSearch: // 次を検索
                    if (selectedIndex != -1)
                        startIndex = Math.Min(selectedIndex + 1, tab.AllCount - 1);
                    else
                        startIndex = 0;
                    break;
                case SEARCHTYPE.PrevSearch: // 前を検索
                    if (selectedIndex != -1)
                        startIndex = Math.Max(selectedIndex - 1, 0);
                    else
                        startIndex = tab.AllCount - 1;
                    break;
                case SEARCHTYPE.DialogSearch: // ダイアログからの検索
                default:
                    if (selectedIndex != -1)
                        startIndex = selectedIndex;
                    else
                        startIndex = 0;
                    break;
            }

            Func<string, bool> stringComparer;
            try
            {
                stringComparer = this.CreateSearchComparer(searchWord, useRegex, caseSensitive);
            }
            catch (ArgumentException)
            {
                MessageBox.Show(Properties.Resources.DoTabSearchText1, Properties.Resources.DoTabSearchText3, MessageBoxButtons.OK, MessageBoxIcon.Error);
                return;
            }

            var reverse = searchType == SEARCHTYPE.PrevSearch;
            var foundIndex = tab.SearchPostsAll(stringComparer, startIndex, reverse)
                .DefaultIfEmpty(-1).First();

            if (foundIndex == -1)
            {
                MessageBox.Show(Properties.Resources.DoTabSearchText2, Properties.Resources.DoTabSearchText3, MessageBoxButtons.OK, MessageBoxIcon.Information);
                return;
            }

            this.SelectListItem(this._curList, foundIndex);
            this._curList.EnsureVisible(foundIndex);
        }