不知道在哪看见一个人写过一个算法的，然后求得结果，不过我又看到一个人用

Dim xmlD As System.Xml.XmlDocument
        Dim xmlP As System.Xml.XPath.XPathNavigator

类似前台写的EVAL就能得到结果。

后台方法计算，非常好，

写一了一个，参考：

Private Function CalculateString(ByVal str As String) As Single
        Dim xmlD As System.Xml.XmlDocument
        Dim xmlP As System.Xml.XPath.XPathNavigator

        Try
            xmlD = New System.Xml.XmlDocument
            xmlP = xmlD.CreateNavigator
            Return xmlP.Evaluate(str)
        Catch ex As Exception
            Return 0
        End Try
    End Function

例：STR=“8*9 —23 + 45/5”
STR=CalculateString（STR）

结果：STR=58
from: csdn