winform双击ListView某行弹出窗体，关闭弹出窗体返回修改选中行的值

 private void lvTags_DoubleClick(object sender, EventArgs e)
        {
            if (lvTags.Items.Count > 0)
            {
                TagsEditor myTags = new TagsEditor();
                int lvIndex = 0;
                foreach (ListViewItem viewItem in this.lvTags.Items)
                {
                    if (viewItem.Selected)
                    {
                        myTags.TagName = viewItem.SubItems[0].Text;
                        lvIndex = viewItem.ListView.SelectedIndices[0];                    }
                }
                if (myTags.ShowDialog() == DialogResult.OK)
                {
                    lvTags.Items[lvIndex].Selected = true;
                    lvTags.Items[lvIndex].SubItems[1].Text = myTags.StartHtml;
                    lvTags.Items[lvIndex].SubItems[2].Text = myTags.EndHtml;                }
            }
          
        }出现错误提示 InvalidArgument=“1”的值对于“index”无效！！！貌似是返回后没获取到选中行。请大大看看。