在VS2015 Update 1中使用可空的長開關語句時,我看到一些奇怪的行爲,在其他Visual Studio版本中沒有看到它按預期方式運行。可空的長開關語句在VS2015中沒有產生預期的輸出
class Program
{
static void Main(string[] args)
{
NullableTest(-1);
NullableTest(0);
NullableTest(1);
NullableTest(2);
NullableTest(null);
}
public static void NullableTest(long? input)
{
string switch1;
switch (input)
{
case 0:
switch1 = "0";
break;
case 1:
switch1 = "1";
break;
default:
switch1 = "d";
break;
}
string switch2;
switch (input)
{
case -1:
switch2 = "-1";
break;
case 0:
switch2 = "0";
break;
case 1:
switch2 = "1";
break;
default:
switch2 = "d";
break;
}
string ifElse;
if (input == 0)
{
ifElse = "0";
}
else if (input == 1)
{
ifElse = "1";
}
else
{
ifElse = "d";
}
Console.WriteLine("Input = {0}, Switch 1 output = {1}, Switch 2 output = {2}, If Else = {3}", input, switch1, switch2, ifElse);
}
此示例代碼產生以下輸出(對準,用於可讀性):
Input = -1, Switch 1 output = d, Switch 2 output = d, If Else = d
Input = 0, Switch 1 output = 0, Switch 2 output = d, If Else = 0
Input = 1, Switch 1 output = d, Switch 2 output = d, If Else = 1
Input = 2, Switch 1 output = d, Switch 2 output = d, If Else = d
Input = , Switch 1 output = d, Switch 2 output = d, If Else = d
我只觀察與空類型此行爲。不可空值類型按預期工作。
注意,這是不相同的行爲是在this question,而不是由一個已經固定在VS2015更新1.我驗證過兩個那些例子正確運行this編譯器故障而引起的。