[导入]Why does my switch statement works differently?

C# does not support an explicit fall through for case blocks (unless the block is empty) 

For an explanation of why, see Why is the C# switch statement designed to not allow fall through, but still require a break? on MSDN

The following code is not legal and will not compile in C#:

switch (x)
{
 
   

  
    
case 0:
  
    
 
      
     
Console.WriteLine(x)
 
     
// do something
 
    
  
    
  
    
case 1:
  
    
 
      
     
Console.WriteLine(x)
 
     
// do something in common with 0
 
    
  
    
  
    
default:
  
    
 
      
     
Console.WriteLine(x)
 
     
// do something in common with 0, 1 and everything else
 
    
  
    
  
    
break;
 
   
}

In order to achieve the same effect in C# the code must be modified as shown below (notice how the control flows are very explicit): 
     

class Test
{
 
   

  
    
static void Main()
{
 
     
 
      
int x = 3;
 
      
 
 
      
switch (x)
 
      
{
 
      
 
       
case 0:
 
       
 
        
// do something
 
         
        
goto case 1;
 
       
 
       
case 1:
 
       
 
        
// do something in common with 0
 
         
        
goto default;
 
       
 
       
default:
 
       
 
        
// do something in common with 0, 1, and anything else
 
         
        
break;
 
       
 
      
 
      
}
 
     
}
 
   
}

文章来源: http://blogs.msdn.com/csharpfaq/archive/2004/07/22/191787.aspx