Question

我们如何切换下面的if -else语句来切换case语句..任何人都可以帮忙...

        if (Webcc1.Contains(licensePartID))
        {
             dtExpiryDate = dtActivatedDate.AddYears(1);
            int isExpiry = DateTime.Compare(dtActivatedDate, dtExpiryDate);
             if (isExpiry >= 0)
             {
                    setError(lblSystemErr, "This action cannot be performed. The subscription period of the license key has expired");
                    return;
              }
         }
        else if (Webcc3.Contains(licensePartID))
        {
           dtExpiryDate = dtActivatedDate.AddYears(3);
           int isExpiry = DateTime.Compare(dtActivatedDate, dtExpiryDate);
            if (isExpiry >= 0)
             {
                  setError(lblSystemErr, "This action cannot be performed. The subscription period of the license key has expired");
                   return;
             }
         }
         else if (Webcc5.Contains(licensePartID))
         {
            dtExpiryDate = dtActivatedDate.AddYears(5);
            int isExpiry = DateTime.Compare(dtActivatedDate, dtExpiryDate);
            if (isExpiry >= 0)
            {
               setError(lblSystemErr, "This action cannot be performed. The subscription period of the license key has expired");
               return;
             }
         }

提前多多感谢....

Answer 1

您不能直接执行此操作，但可以使用~~按位运算~~三元条件将if ... else if转换为switch语句： <击>

<击>

var flags = (Webcc1.Contains(licensePartID)) ? 1 : 0;
flags |= (Webcc3.Contains(licensePartID)) ? 2 : 0;
flags |= (Webcc5.Contains(licensePartID)) ? 4 : 0;

<击>

var flags = (Webcc1.Contains(licensePartID)) ? 1 :
            (Webcc3.Contains(licensePartID)) ? 2 :
            (Webcc5.Contains(licensePartID)) ? 4 :
            0;
switch(flags)
{
    case 1:
        dtExpiryDate = dtActivatedDate.AddYears(1);
        int isExpiry = DateTime.Compare(dtActivatedDate, dtExpiryDate);
        if (isExpiry >= 0)
        {
            setError(lblSystemErr, "This action cannot be performed. The subscription period of the license key has expired");
            return;
        }
        break;
    case 2:
        dtExpiryDate = dtActivatedDate.AddYears(3);
        int isExpiry = DateTime.Compare(dtActivatedDate, dtExpiryDate);
        if (isExpiry >= 0)
        {
            setError(lblSystemErr, "This action cannot be performed. The subscription period of the license key has expired");
            return;
        }
        break;
    case 4:
        dtExpiryDate = dtActivatedDate.AddYears(5);
        int isExpiry = DateTime.Compare(dtActivatedDate, dtExpiryDate);
        if (isExpiry >= 0)
        {
            setError(lblSystemErr, "This action cannot be performed. The subscription period of the license key has expired");
            return;
        }
        break;
}
}

但是，您提供的代码示例可以而且应该更短，因为条件之间唯一更改的是添加的年数，您可以简单地执行此操作：

var numberOfYears = (Webcc1.Contains(licensePartID)) ? 1 :
                    (Webcc3.Contains(licensePartID)) ? 3 :
                    (Webcc5.Contains(licensePartID)) ? 5 :
                    0; // or some other default number if needed
dtExpiryDate = dtActivatedDate.AddYears(numberOfYears);
int isExpiry = DateTime.Compare(dtActivatedDate, dtExpiryDate);
if (isExpiry >= 0)
{
    setError(lblSystemErr, "This action cannot be performed. The subscription period of the license key has expired");
    return;
}

切换elseif切换案例

1 个答案: