nunit问题

public class Class1
{
  public static stirng Field1="Hello World!";
  public static bool b1=fasle;
  public Class1(){}
  public switch(i)
  {
     if (i==1)
     {
        b1=true;
        //1语句
      }
      else if(i==2)
      {
         //2语句
       }
        else(i==3)
         {
            //3语句
         }
  }
}