Evaluate mathematical expression from a string using VB

Question

I want to calculate a arithmetic expression from a string using VB, any ideas ?

As an example : "x+2" from a textbox, I want to evaluate the expression

Answer 1

Dim equation As String = "2+6/2"
Dim result = New DataTable().Compute(equation, Nothing)

Answer 2

you can use NCalc for this. It also accepts parameters like x, y, z,...

Dim e As Expression = new Expression("2 + 3 * 5")
Msgbox(17 = e.Evaluate())

Answer 3

You can use mxparser library for this purpose.Give a reference to mxparser.dll in your project by clicking ADD Reference button of Microsoft Visual Studio.The mxparser library source code or latest dll file can be from www.mathparser.org.The mXparser is a Math Parser for Java, Android, C# .NET (CLS) Libraries.

Imports org.mariuszgromada.math.mxparser
Private Function evaluate(ByVal str As String) AS Double
Dim expr As Expression = New Expression(str)
DIM d1 As Double
d1=0
d1=expr.calculate()
return d1
End Function

Call to the function can be as follows.

DIM str as String
str=""
str=((45^5)/45))*(5*6)

Dim d as Double
d=0
d=evaluate(str)
MsgBox(" The result of the expression is   " + d.ToString)