public void TestChecked()
        {
            NativeTree tree = new NativeTree(testDlg.IdentifyFromDialogId(1041));
            tree.EmulateCheck(tree.Nodes[0], true);
            Assert.IsTrue(tree.IsChecked(tree.Nodes[0]));
            tree.EmulateCheck(tree.Nodes[0], false);
            Assert.IsFalse(tree.IsChecked(tree.Nodes[0]));

            //非同期でも同様の効果があることの確認。
            Async a = new Async();
            tree.EmulateCheck(tree.Nodes[0], true, a);
            while (!a.IsCompleted)
            {
                Thread.Sleep(10);
            }
            Assert.IsTrue(tree.IsChecked(tree.Nodes[0]));
        }