怎么样去掉代码中的DOTO语句，分不多，请各位帮忙！！

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;

namespace WindowsApplication1
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        private void Form1_Load(object sender, EventArgs e)
        {

        }
        public void aa(int b, bool a, int c)
        {
            switch (b)
            {
                case 1:
                    if (a)
                    {
                        break;
                    }
                    goto Label_2A7D;

                case 2:
                    if (a)
                    {
                        goto Label_29DD;
                    }
                    goto Label_2A7D;

                default:
                    goto Label_2A7D;
            }
            if (c != 1)
            {
                throw new Exception(” c”);
            }
            goto Label_2A7D;
        Label_29DD: ;

            MessageBox.Show(“Label_29DD”);

        Label_2A7D:

            MessageBox.Show(“Label_2A7D”);
        }

        private void button1_Click(object sender, EventArgs e)
        {
            aa(1, false, 1);
            aa(1, true, 1);
            aa(2, false, 1);
            aa(2, true, 1);            
        }
    }
}