OpenTween.MediaSelector.BeginSelection C# (CSharp) Method

        private void BeginSelection(IMediaItem[] items)
        {
            if (items == null || items.Length == 0)
            {
                BeginSelection();
                return;
            }

            var service = this.SelectedService;
            if (service == null) return;

            var count = Math.Min(items.Length, service.MaxMediaCount);
            if (!this.Visible || count > 1)
            {
                // 非表示時または複数のファイル指定は新規選択として扱う
                SetImagePageCombo();

                this.BeginSelecting?.Invoke(this, EventArgs.Empty);

                this.Visible = true;
            }
            this.Enabled = true;

            if (count == 1)
            {
                ImagefilePathText.Text = items[0].Path;
                AlternativeTextBox.Text = items[0].AltText;
                ImageFromSelectedFile(items[0], false);
            }
            else
            {
                for (int i = 0; i < count; i++)
                {
                    var index = ImagePageCombo.Items.Count - 1;
                    if (index == 0)
                    {
                        ImagefilePathText.Text = items[i].Path;
                        AlternativeTextBox.Text = items[i].AltText;
                    }
                    ImageFromSelectedFile(index, items[i], false);
                }
            }
        }

        public void BeginSelection_MultiImageTest()
        {
            using (var twitter = new Twitter())
                using (var mediaSelector = new MediaSelector {
                    Visible = false, Enabled = false
                })
                {
                    twitter.Initialize("", "", "", 0L);
                    mediaSelector.Initialize(twitter, TwitterConfiguration.DefaultConfiguration(), "Twitter");

                    var images = new[] { "Resources/re.gif", "Resources/re1.png" };
                    mediaSelector.BeginSelection(images);

                    // 3 ページ目まで選択可能な状態
                    var pages = mediaSelector.ImagePageCombo.Items;
                    Assert.Equal(new[] { "1", "2", "3" }, pages.Cast <object>().Select(x => x.ToString()));

                    // 1 ページ目が表示されている
                    Assert.Equal("1", mediaSelector.ImagePageCombo.Text);
                    Assert.Equal(Path.GetFullPath("Resources/re.gif"), mediaSelector.ImagefilePathText.Text);

                    using (var imageStream = File.OpenRead("Resources/re.gif"))
                        using (var image = MemoryImage.CopyFromStream(imageStream))
                        {
                            Assert.Equal(image, mediaSelector.ImageSelectedPicture.Image);
                        }
                }
        }