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;
    }

你的意思是?

if(number >= 1 && number <= 100)

or

bool TestRange (int numberToCheck, int bottom, int top)
{
  return (numberToCheck >= bottom && numberToCheck <= top);
}

我使用下一个“优雅”的解决方案:

using static System.Linq.Enumerable;

int x = 30;
if (Range(1,100).Contains(x))  //true

来自微软文档

using static指令适用于任何具有静态成员(或嵌套类型)的类型，即使它也具有实例成员。但是，实例成员只能通过类型实例调用。

你可以访问一个类型的静态成员，而不需要用类型名限定访问:

但这对许多人来说并不简单，因为Enumerable。Range有第一个参数start和第二个参数count。 所以这种检查可能在特定情况下有用，比如当你使用Enumerable时。范围的foreach循环，在开始之前，您想知道，如果循环将执行。

例如:

        int count = 100;
        int x = 30;

        if (!Range(1, count).Contains(x)) {
            Console.WriteLine("Do nothing!");
            return;
        }

        foreach (var i in Range(1, count)) {
            // Some job here
        }

In C, if time efficiency is crucial and integer overflows will wrap, one could do if ((unsigned)(value-min) <= (max-min)) .... If 'max' and 'min' are independent variables, the extra subtraction for (max-min) will waste time, but if that expression can be precomputed at compile time, or if it can be computed once at run-time to test many numbers against the same range, the above expression may be computed efficiently even in the case where the value is within range (if a large fraction of values will be below the valid range, it may be faster to use if ((value >= min) && (value <= max)) ... because it will exit early if value is less than min).

不过，在使用这样的实现之前，请先对目标机器进行基准测试。在某些处理器上，由两部分组成的表达式可能在所有情况下都更快，因为两个比较可能是独立完成的，而在减法和比较方法中，减法必须在比较执行之前完成。

我会创建一个Range对象，就像这样:

public class Range<T> where T : IComparable
{
    public T InferiorBoundary{get;private set;}
    public T SuperiorBoundary{get;private set;}

    public Range(T inferiorBoundary, T superiorBoundary)
    {
        InferiorBoundary = inferiorBoundary;
        SuperiorBoundary = superiorBoundary;
    }

    public bool IsWithinBoundaries(T value){
        return InferiorBoundary.CompareTo(value) > 0 && SuperiorBoundary.CompareTo(value) < 0;
    }
}

那么你可以这样使用它:

Range<int> myRange = new Range<int>(1,999);
bool isWithinRange = myRange.IsWithinBoundaries(3);

这样你就可以在其他类型中重用它。

因为所有其他答案都不是我发明的，这里只是我的实现:

public enum Range
{
    /// <summary>
    /// A range that contains all values greater than start and less than end.
    /// </summary>
    Open,
    /// <summary>
    /// A range that contains all values greater than or equal to start and less than or equal to end.
    /// </summary>
    Closed,
    /// <summary>
    /// A range that contains all values greater than or equal to start and less than end.
    /// </summary>
    OpenClosed,
    /// <summary>
    /// A range that contains all values greater than start and less than or equal to end.
    /// </summary>
    ClosedOpen
}

public static class RangeExtensions
{
    /// <summary>
    /// Checks if a value is within a range that contains all values greater than start and less than or equal to end.
    /// </summary>
    /// <param name="value">The value that should be checked.</param>
    /// <param name="start">The first value of the range to be checked.</param>
    /// <param name="end">The last value of the range to be checked.</param>
    /// <returns><c>True</c> if the value is greater than start and less than or equal to end, otherwise <c>false</c>.</returns>
    public static bool IsWithin<T>(this T value, T start, T end) where T : IComparable<T>
    {
        return IsWithin(value, start, end, Range.ClosedOpen);
    }

    /// <summary>
    /// Checks if a value is within the given range.
    /// </summary>
    /// <param name="value">The value that should be checked.</param>
    /// <param name="start">The first value of the range to be checked.</param>
    /// <param name="end">The last value of the range to be checked.</param>
    /// <param name="range">The kind of range that should be checked. Depending on the given kind of range the start end end value are either inclusive or exclusive.</param>
    /// <returns><c>True</c> if the value is within the given range, otherwise <c>false</c>.</returns>
    public static bool IsWithin<T>(this T value, T start, T end, Range range) where T : IComparable<T>
    {
        if (value == null)
            throw new ArgumentNullException(nameof(value));

        if (start == null)
            throw new ArgumentNullException(nameof(start));

        if (end == null)
            throw new ArgumentNullException(nameof(end));

        switch (range)
        {
            case Range.Open:
                return value.CompareTo(start) > 0
                       && value.CompareTo(end) < 0;
            case Range.Closed:
                return value.CompareTo(start) >= 0
                       && value.CompareTo(end) <= 0;
            case Range.OpenClosed:
                return value.CompareTo(start) > 0
                       && value.CompareTo(end) <= 0;
            case Range.ClosedOpen:
                return value.CompareTo(start) >= 0
                       && value.CompareTo(end) < 0;
            default:
                throw new ArgumentException($"Unknown parameter value {range}.", nameof(range));
        }
    }
}

然后你可以这样使用它:

var value = 5;
var start = 1;
var end = 10;

var result = value.IsWithin(start, end, Range.Closed);