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我今天在我的软件上运行测试，发现它产生的一些值不正确。

我决定单步执行代码并注意到当悬停在所述空上时我分配给用户窗体上的文本框值的变量，即使将鼠标悬停在分配给它的文本框上时，用户输入的值也会显示。

例如，

n = BiTimeSteps_TextBox.Value

当悬停在

n = empty

虽然

BiTimeSteps_TextBox.Value = 2

悬停时。

所以说我有一个公式在那之后不久

d = n*2 ,

n 当悬停在上面时表示为空，而 d 在不应该时设为 0。

有人告诉我，如果我把它换成

BiTimeSteps_TextBox.Value = n

它应该得到承认，但仍然没有。

这可能是什么原因造成的？

请参阅下面的完整代码：（它旨在使用二叉树定价方法为期权定价）

S = BiCurrentStockPrice_TextBox.Value
X = BiStrikePrice_TextBox.Value
r = BiRisk_Free_Rate_TextBox.Value
T = BiexpTime_TextBox.Value
Sigma = BiVolatility_TextBox.Value
n = BiTimeSteps_TextBox.Value

Dim i, j, k As Integer
Dim p, V, u, d, dt As Double


dt = T / n ' This finds the value of dt
u = Exp(Sigma * Sqr(dt)) 'formula for the up factor
d = 1 - u 'formula for the down factor

'V value of option

'array having the values
Dim bin() As Double 'is a binomial arrays, it stores the value of each node, there is a loop

'work out the risk free probability

p = (1 + r - d) / (u - d)

'probability of going up

ReDim bin(n + 1) As Double

'it redims the array, and n+1 is used because it starts from zero
'------------------------------------------------------------------------------------------------------------------------------
''European Call

If BiCall_CheckBox = True Then

    For i = 0 To n 'payoffs = value of option at final time

        bin(i + 1) = Application.WorksheetFunction.Max(0, (u ^ (n - i)) * (d ^ i) * S - X) 

       'It takes the max payoff or 0

       Cells(i + 20, n + 2) = bin(i + 1) 'to view payoffs on the isolated column on the right

    Next i


End If

'european put

If BiPut_CheckBox = True Then

    For i = 0 To n 'payoffs = value of option at final time

        bin(i + 1) = Application.WorksheetFunction.Max(0, X - (S * (u * (n - i)) * (d * i))) 

        ' European Put- It takes the max payoff or 0

        Cells(i + 20, n + 2) = bin(i + 1) 'to view payoffs on the isolated column on the right

    Next i

End If

For k = 1 To n 'backward column loop

    For j = 1 To (n - k + 1) 'loop down the column loop

        bin(j) = (p * bin(j) + (1 - p) * bin(j + 1)) / (1 + r)

        Cells(j + 19, n - k + 2) = bin(j) 
        '' print the values along the column, view of tree

    Next j

Next k

Worksheets("Binomial").Cells(17, 2) = bin(1) ' print of the value V
BiOptionPrice_TextBox = bin(1)
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