Silverlight中打开文件和保存文件

打开文件：

var dialog = new OpenFileDialog { Multiselect = false };
            var result = dialog.ShowDialog();
            if (result == true)
            {
                    using (var stream = dialog.File.OpenRead())
                    {
                        var buffer = new byte[stream.Length];
                        stream.Read(buffer, 0, buffer.Length);
                        var xaml = System.Text.Encoding.UTF8.GetString(buffer, 0, buffer.Length);
                        .............................
                        ................................
                    }
             }

保存文件：

var dialog = new SaveFileDialog();
　　　　　　  dialog.Filter="文本文件(*.txt)|*.txt";
            var result = dialog.ShowDialog();
            //dialog.Filter = "文本文件|*.txt";

            if (result == true)
            {
                using (var stream = dialog.OpenFile())
                {
                    Byte[] fileContent = Encoding.UTF8.GetBytes(saveXaml+strAll.ToString());
                    stream.Write(fileContent, 0, fileContent.Length);
                    stream.Close();
                }
            }