C#执行EXE文件与输出消息的提取操作

//进程的名称
string fileName = "cmd.exe";
//测试参数
string para = @"avrdude\avrdude.exe -C avrdude\avrdude.conf -v -p atmega32u4 -c avr109 -P " + portname+" -b 57600 -D -U flash:w:node.hex:i"; 
//声明
Process p = new Process();

p.StartInfo.CreateNoWindow = true;         // 不创建新窗口    
p.StartInfo.UseShellExecute = false;       //不启用shell启动进程  
p.StartInfo.RedirectStandardInput = true;  // 重定向输入    
p.StartInfo.RedirectStandardOutput = true; // 重定向标准输出    
p.StartInfo.RedirectStandardError = true;  // 重定向错误输出  
p.StartInfo.FileName = fileName;

p.Start();

p.StandardInput.WriteLine(para + "&exit");
p.StandardInput.AutoFlush = true;
p.StandardInput.Close();

p.StandardOutput.ReadToEnd();
string output = p.StandardError.ReadToEnd();
//  p.OutputDataReceived += new DataReceivedEventHandler(processOutputDataReceived);
p.WaitForExit();//参数单位毫秒，在指定时间内没有执行完则强制结束，不填写则无限等待
p.Close();
AddInfo(output);

public void exec(string exePath, string parameters)
        {
            System.Diagnostics.ProcessStartInfo psi =
   new System.Diagnostics.ProcessStartInfo();
            psi.RedirectStandardOutput = true;
            psi.RedirectStandardError = true;
            psi.WindowStyle = System.Diagnostics.ProcessWindowStyle.Hidden;
            psi.UseShellExecute = false;
            psi.FileName = exePath;
            psi.Arguments = parameters;
            System.Diagnostics.Process process = System.Diagnostics.Process.Start(psi);
            System.IO.StreamReader outputStreamReader = process.StandardOutput;
            System.IO.StreamReader errStreamReader = process.StandardError;
            process.WaitForExit(2000);
            if (process.HasExited)
            {
                string output = outputStreamReader.ReadToEnd();
                string error = errStreamReader.ReadToEnd();
                MessageBox.Show(output);
                MessageBox.Show(error);
            }
 
        }

public void exec(string exePath, string parameters)
        {
            Process process = new System.Diagnostics.Process();
            process.StartInfo.FileName = exePath;
            process.StartInfo.Arguments = parameters;
            process.StartInfo.UseShellExecute = false;
            process.StartInfo.CreateNoWindow = true;
            process.StartInfo.RedirectStandardOutput = true;
            process.Start();
            process.BeginOutputReadLine();
            process.OutputDataReceived += new DataReceivedEventHandler(processOutputDataReceived);
        }
 
        private void processOutputDataReceived(object sender, DataReceivedEventArgs e)
        {
            MessageBox.Show(e.Data); 
        }