您可以尝试使用 Linq 来查询validationList：

  using System.Linq;

  ... 

  int distributeVal = 7;

  List<int> validationList = new List<int>() { 2,2,3 };

  ...

  // validationList = if you want to "update" validationList
  var result = validationList
    .TakeWhile(_ => distributeVal > 0)   // Keep on while we have a value to distribute
    .Select(item => {                    // Distribution
      int newItem = item > distributeVal // two cases: 
        ? distributeVal                  //   we can distribute partialy  
        : item;                          //   or take the entire item

      distributeVal -= newItem;          // newItem has been distributed  

      return newItem;
    })
    .ToList();

 Console.Write(string.Join(",",result));

结果：

 2,1

这是一个非Linq答案，它使用简单函数来计算这些值：

private List<int> GetValidationList(int distributeVal,List<int> validationList)
{
    List<int> outputList = new List<int>();
    int runningCount = 0;

    for (int i = 0; i < validationList.Count; i++)
    {
        int nextValue;

        if (runningCount + validationList[i] > distributeVal)
            nextValue = distributeVal - runningCount;
        else
            nextValue = validationList[i];

        outputList.Add(nextValue);
        runningCount += nextValue;
        if (runningCount >= distributeVal)
            break;
    }

    return outputList;
}

本质上，遍历每个值并将其添加到输出中（如果该值低于所需总数）。如果不是，则计算差异并将其添加到输出中。

使用以下值运行：

List<int> result;
result = GetValidationList(7,new List<int> { 5,5,5 });
result = GetValidationList(7,6,new List<int> { 6,5 });
result = GetValidationList(8,new List<int> { 2,3 });
result = GetValidationList(8,new List<int> { 1 });
result = GetValidationList(8,7 });
result = GetValidationList(2,5 });
result = GetValidationList(3,new List<int> { 1,1,45,16 });
result = GetValidationList(0,50,50 });

提供此输出（在List<int>中）：

5,2
5,2
6,1
2,2
1
5,1
2
1,1
1,7
0

Linq支持的最短方法：

    private List<int> Validations(int value,List<int> validations)
    {
        List<int> outputList = new List<int>();
        int runningCount = 0;

        foreach (var nextValue in validations.Select(t => runningCount + t > value ? value - runningCount : t))
        {
            outputList.Add(nextValue);
            runningCount += nextValue;
            if (runningCount >= value) break;
        }

        return outputList;
    }

用法：

var result = Validations(7,1 });