Control cannot fall through from one case to another?

[C# Programming]

End Google Ads 201810 - BS.net 01 --> hi
I have these code . What could cause above error ? Thanks

state=1
switch (state)
{
case 1:
//do something

goto case 2;

case 2:

//do something

goto case 3;

case 3:
//do something
goto case 4;

............


case 100:

//do something

}