关于优雅，最接近数学符号(a <= x <= b)的方法略微提高了可读性:

public static bool IsBetween(this int value, int min, int max)
{
    return min <= value && value <= max;
}

为了进一步说明:

public static bool IsOutside(this int value, int min, int max)
{
    return value < min || max < value;
}

如果你想写更多的代码而不是简单的If，也许你可以: 创建一个名为IsBetween的扩展方法

public static class NumberExtensionMethods
{
    public static bool IsBetween(this long value, long Min, long Max)
    {
        // return (value >= Min && value <= Max);
        if (value >= Min && value <= Max) return true;
        else return false;
    }
}

...

// Checks if this number is between 1 and 100.
long MyNumber = 99;
MessageBox.Show(MyNumber.IsBetween(1, 100).ToString());

Addendum: it's worth noting that in practice you very rarely "just check for equality" (or <, >) in a codebase. (Other than in the most trivial situations.) Purely as an example, any game programmer would use categories something like the following in every project, as a basic matter. Note that in this example it (happens to be) using a function (Mathf.Approximately) which is built in to that environment; in practice you typically have to carefully develop your own concepts of what comparisons means for computer representations of real numbers, for the type of situation you are engineering. (Don't even mention that if you're doing something like, perhaps a controller, a PID controller or the like, the whole issue becomes central and very difficult, it becomes the nature of the project.) BY no means is the OP question here a trivial or unimportant question.

private bool FloatLessThan(float a, float b)
    {
    if ( Mathf.Approximately(a,b) ) return false;
    if (a<b) return true;
    return false;
    }

private bool FloatLessThanZero(float a)
    {
    if ( Mathf.Approximately(a,0f) ) return false;
    if (a<0f) return true;
    return false;
    }

private bool FloatLessThanOrEqualToZero(float a)
    {
    if ( Mathf.Approximately(a,0f) ) return true;
    if (a<0f) return true;
    return false;
    }

这些是一些可以提供帮助的扩展方法

  public static bool IsInRange<T>(this T value, T min, T max)
where T : System.IComparable<T>
    {
        return value.IsGreaterThenOrEqualTo(min) && value.IsLessThenOrEqualTo(max);
    }


    public static bool IsLessThenOrEqualTo<T>(this T value, T other)
         where T : System.IComparable<T>
    {
        var result = value.CompareTo(other);
        return result == -1 || result == 0;
    }


    public static bool IsGreaterThenOrEqualTo<T>(this T value, T other)
         where T : System.IComparable<T>
    {
        var result = value.CompareTo(other);
        return result == 1 || result == 0;
    }

就像其他人说的，使用简单的if。

你应该考虑一下顺序。

e.g

1 <= x && x <= 100

容易读吗

x >= 1 && x <= 100

像这样的怎么样?

if (theNumber.isBetween(low, high, IntEx.Bounds.INCLUSIVE_INCLUSIVE))
{
}

扩展方法如下(已测试):

public static class IntEx
{
    public enum Bounds 
    {
        INCLUSIVE_INCLUSIVE, 
        INCLUSIVE_EXCLUSIVE, 
        EXCLUSIVE_INCLUSIVE, 
        EXCLUSIVE_EXCLUSIVE
    }

    public static bool isBetween(this int theNumber, int low, int high, Bounds boundDef)
    {
        bool result;
        switch (boundDef)
        {
            case Bounds.INCLUSIVE_INCLUSIVE:
                result = ((low <= theNumber) && (theNumber <= high));
                break;
            case Bounds.INCLUSIVE_EXCLUSIVE:
                result = ((low <= theNumber) && (theNumber < high));
                break;
            case Bounds.EXCLUSIVE_INCLUSIVE:
                result = ((low < theNumber) && (theNumber <= high));
                break;
            case Bounds.EXCLUSIVE_EXCLUSIVE:
                result = ((low < theNumber) && (theNumber < high));
                break;
            default:
                throw new System.ArgumentException("Invalid boundary definition argument");
        }
        return result;
    }
}

2022年6月

int id = 10;
if(Enumerable.Range(1, 100).Select(x => x == id).Any()) // true