用C#打开文件对话框，我设置了过滤条件为何还是全部显示出来?

Question

OpenFileDialog openFileDialog = new OpenFileDialog();
            openFileDialog.InitialDirectory = "c:\\";
            openFileDialog.Filter = "xls|";
            openFileDialog.RestoreDirectory = true;
            openFileDialog.FilterIndex = 1;
            if (openFileDialog.ShowDialog() == DialogResult.OK)
            {
        ..............
            }上面的结果将全部显示出来文件，而不是只以xls显示出来谢谢!

Answer 1

openFileDialog.Filter = "xls|*.xls||";

Answer 2

openFileDialog1.Filter = "Excel Files (.xls)|*.xls|All Files (*.*)|*.*";