private void cmdDeleteFiles_Click(object sender, EventArgs e) { if (MessageBox.Show(this, "Whether you want to delete the selection file?", "warn", MessageBoxButtons.YesNo, MessageBoxIcon.Question) == DialogResult.Yes) { List <string> files = new List <string>(); foreach (ListViewItem item in lstFiles.SelectedItems) { files.Add(item.Text); } DeleteFiles del = mClient.DeleteFiles(GetSelectItem().Text, files); mResultHandler[del.ID] = (r) => { mClient.ListFiles(GetSelectItem().Text); }; } }