try
 {
     Config cfg = new Config();
     var file = "";
     if (saveFileDialog1.ShowDialog() == DialogResult.OK)
     {
         file = saveFileDialog1.FileName;//（获取整个文件名）
         cfg.WriteConfigFile(command, file);
         MessageBox.Show("file:" + file);
     }
 }
catch (Exception)
{
    OutputMessage("检查软件路径下面是否有\"Newtonsoft.Json.dll\"文件");
}

this.openFileDialog1.Filter = "Json文件|*.json";