在C#中计算值数组(从Excel转换公式)

Question

我目前正在构建一个半复杂的计算器,它基本上是我提供的Excel电子表格的转换.

我已经把大部分内容钉在了但是在Excel电子表格中有一个部分,其中在6行和7列之间进行了多次计算,但问题在于计算没有按照特定的顺序发生.

因此,例如,Row0[Column1]使用计算,并使用(Row2[Column4] * Row2[Column5])等Row1[Column4]计算(Row4[Column2] / Row5[Column1])..你得到了想法.

我曾考虑使用2D数组,但我担心这些值会按特定顺序计算,因此在达到它们时没有任何价值.据我所知,ROW1将首先计算,然后行2,ROW3,等等.

因此,如果没有为我的Excel电子表格中的每个单元格创建变量(并对其进行适当排序),有没有办法可以使用C#计算出来？

我真的很感激任何帮助,建议,指针,无论你认为什么都可能 - 我很乐意听到它!

编辑实现@dtb提供的Lazy类之后,我得到了以下代码.它是我提供的Excel电子表格中的内容的直接副本,包括指针和计算.

var sr = new Lazy<decimal>[6, 6];
sr[0, 0] = new Lazy<decimal>(() => sr[1, 0].Value - eNumber);
sr[0, 3] = new Lazy<decimal>(() => sr[0, 4].Value - sr[1, 0].Value - sr[1, 4].Value);
sr[0, 4] = new Lazy<decimal>(() => sr[0, 0].Value * edD);
sr[0, 5] = new Lazy<decimal>(() => sr[0, 0].Value);

sr[1, 0] = new Lazy<decimal>(() => sr[1, 5].Value);
sr[1, 4] = new Lazy<decimal>(() => sr[1, 0].Value * edD);
sr[1, 5] = new Lazy<decimal>(() => sr[2, 0].Value + sr[2, 5].Value);

sr[2, 0] = new Lazy<decimal>(() => eNumber * rRate);
sr[2, 4] = new Lazy<decimal>(() => sr[2, 0].Value * hdD);
sr[2, 5] = new Lazy<decimal>(() => sr[1, 5].Value);

sr[3, 1] = new Lazy<decimal>(() => sr[2, 5].Value);

sr[4, 2] = new Lazy<decimal>(() => eNumber * (ePc / 100) + sr[2, 0].Value * (hlPc / 100) - sr[3, 1].Value);

sr[5, 0] = new Lazy<decimal>(() => (sr[0, 0].Value + sr[1, 0].Value + sr[2, 0].Value) / ePerR);
sr[5, 2] = new Lazy<decimal>(() => sr[5, 0].Value / rLifecycle);
sr[5, 4] = new Lazy<decimal>(() => sr[5, 2].Value);
sr[5, 5] = new Lazy<decimal>(() => sr[5, 0].Value + sr[5, 2].Value - sr[5, 4].Value);

但是我收到以下错误
ValueFactory attempted to access the Value property of this instance.

谷歌搜索错误已经返回了一堆垃圾搜索类型的网站.

马尔科

Answer 1

看看懒惰评估:

var table = new Lazy<int>[2, 2];

table[0, 0] = new Lazy<int>(() => table[1, 1].Value * 2);
table[0, 1] = new Lazy<int>(() => 42);
table[1, 0] = new Lazy<int>(() => 100);
table[1, 1] = new Lazy<int>(() => table[0, 1].Value + table[1, 0].Value);

for (int i = 0; i < 2; i++)
for (int j = 0; j < 2; j++)
{
    Console.WriteLine("Row = {0}  Column = {1}  Value = {2}",
                             i,            j,           table[i, j].Value);
}

注意表单元格的内容是如何以任意顺序定义的.只要单元格之间没有循环依赖关系,它就会找出顺序本身.

输出:

Row = 0  Column = 0  Value = 284
Row = 0  Column = 1  Value = 42
Row = 1  Column = 0  Value = 100
Row = 1  Column = 1  Value = 142

LINQ-to-Lazy的可读性略高一些:

var table = new Lazy<int>[2, 2];

table[0, 0] = from t in table.AsLazy()
              from x in t[1, 1]
              select 2 * x;
table[0, 1] = 42.AsLazy();
table[1, 0] = 100.AsLazy();
table[1, 1] = from t in table.AsLazy()
              from a in t[0, 1]
              from b in t[1, 0]
              select a + b;

运用

static class LazyExtensions
{
    public static Lazy<TResult> SelectMany<TSource, TCollection, TResult>(this Lazy<TSource> source, Func<TSource, Lazy<TCollection>> collectionSelector, Func<TSource, TCollection, TResult> resultSelector)
    {
        return new Lazy<TResult>(() => resultSelector(source.Value, collectionSelector(source.Value).Value));
    }

    public static Lazy<TSource> AsLazy<TSource>(this TSource value)
    {
        return new Lazy<TSource>(() => value);
    }
}

.NET 4.0的Lazy <T>类的自定义替换:

sealed class MyLazy<T>
{
    private readonly Func<T> valueFactory;
    private T value;
    private bool valueCreated;

    public MyLazy(Func<T> valueFactory)
    {
        if (valueFactory == null)
        {
            throw new ArgumentNullException("valueFactory");
        }
        this.valueFactory = valueFactory;
    }

    public bool IsValueCreated
    {
        get { return this.valueCreated; }
    }

    public T Value
    {
        get
        {
            if (!this.valueCreated)
            {
                this.value = this.valueFactory();
                this.valueCreated = true;
            }
            return this.value;
        }
    }
}