private void txtSearch_TextChanged(object sender, EventArgs e) { if (SampleTextList is null) { return; // throw new NullReferenceException("SearchList is null"); } lbSearchBox.Items.Clear(); var getTexts = TextSearch.SearchWord(SampleTextList, txtSearch.Text.Trim(), out string searchPattern); lbSearchBox.Items.AddRange(getTexts.ToArray()); lbPattern.Text = $"검색패턴 : {searchPattern}"; }