Question

当试图运行这个时，我的const会变得圆润从double转换为int。有没有办法避免从发生中走出来？

    const double ACTIVTY_LEVEL1 = 1.2;
    const double ACTIVTY_LEVEL2 = 1.375;
    const double ACTIVTY_LEVEL3 = 1.55;
    const double ACTIVTY_LEVEL4 = 1.725;
    const double ACTIVTY_LEVEL5 = 1.9;           

    int activityLevel = lstActivityLevel.SelectedIndex;
        switch (activityLevel)
        {
            case 0:
                activityLevel = Convert.ToInt32(ACTIVTY_LEVEL1);
                break;

            case 1:
                activityLevel = Convert.ToInt32(ACTIVTY_LEVEL2);
                break;

            case 2:
                activityLevel = Convert.ToInt32(ACTIVTY_LEVEL3);
                break;

            case 3:
                activityLevel = Convert.ToInt32(ACTIVTY_LEVEL4);
                break;

            case 4:
                activityLevel = Convert.ToInt32(ACTIVTY_LEVEL5);
                break;
        }

Answer 1

在我看来，当你不应该重新使用activityLevel变量时。我怀疑你真的double是double[] activityLevels = new [] { 1.2, 1.375, 1.55, 1.725, 1.9 }; double activityLevel = activityLevels[lstActivityLevel.SelectedIndex - 1];。

以下是您应该如何对此进行编码：

{{1}}

Answer 2

整数不能有小数位，因此从double转换为int时，小数位后的所有内容都会被删除。

Answer 3

您似乎希望将activityLevel设置为const varialbe之一。这是方法：

const double ACTIVTY_LEVEL1 = 1.2;
const double ACTIVTY_LEVEL2 = 1.375;
const double ACTIVTY_LEVEL3 = 1.55;
const double ACTIVTY_LEVEL4 = 1.725;
const double ACTIVTY_LEVEL5 = 1.9;

double activityLevel = 0;
switch (lstActivityLevel.SelectedIndex)
{
    case 0:
        activityLevel = ACTIVTY_LEVEL1;
        break;

    case 1:
        activityLevel = ACTIVTY_LEVEL2;
        break;

    case 2:
        activityLevel = ACTIVTY_LEVEL3;
        break;

    case 3:
        activityLevel = ACTIVTY_LEVEL4;
        break;

    case 4:
        activityLevel = ACTIVTY_LEVEL5;
        break;
}
lblBMRResult.Text = (BMR * activityLevel).ToString();

转换为int时，double如何舍入？

3 个答案: