C# / VB.NET - Somma sottoforma di stringa

Salve a tutti. Sò che per voi questo è banale, ma per me è un problema (: Ho una textbox con una somma scritta così "4 + 10". Cliccando un bottone vorrei che il msgbox riportasse il risultato "14" e non il testo vero e proprio "4 + 10"! Come posso fare?

Non è affatto banale.

Un esempio di codice trovato da qualche parte ...

Imports System.CodeDom.Compiler
Imports System.Reflection

Module Module1

    Private Function ProcessCommand(ByVal command As String) As Double
        Dim MyProvider As New VBCodeProvider 'Create a new VB Code Compiler
        Dim cp As New CompilerParameters     'Create a new Compiler parameter object.
        cp.GenerateExecutable = False        'Don't create an object on disk
        cp.GenerateInMemory = True           'But do create one in memory.
        'If cp.OutputAssembly is used with a VBCodeProvider, it seems to want to read before it is executed.  
        'See C# CodeBank example for explanation of why it was used.

        'the below is an empty VB.NET Project with a function that simply returns the value of our command parameter.
        Dim TempModuleSource As String = "Imports System" & Environment.NewLine & _
                                         "Namespace ns " & Environment.NewLine & _
                                         "Public Class class1" & Environment.NewLine & _
                                         "Public Shared Function Evaluate()" & Environment.NewLine & _
                                         "Return " & command & Environment.NewLine & _
                                         "End Function" & Environment.NewLine & _
                                         "End Class" & Environment.NewLine & _
                                         "End Namespace"
        'Create a compiler output results object and compile the source code.
        Dim cr As CompilerResults = MyProvider.CompileAssemblyFromSource(cp, TempModuleSource)
        If cr.Errors.Count > 0 Then
            'If the expression passed is invalid or "", the compiler will generate errors.
            Throw New ArgumentOutOfRangeException("Invalid Expression - please use something VB could evaluate")
        Else
            'Find our Evaluate method.
            Dim methInfo As MethodInfo = cr.CompiledAssembly.GetType("ns.class1").GetMethod("Evaluate")
            'Invoke it on nothing, so that we can get the return value
            Return Convert.ToDouble(methInfo.Invoke(Nothing, Nothing))
        End If
    End Function



    Sub Main()
        Console.WriteLine(ProcessCommand("1+1").ToString()) 'Displays 2
        Console.WriteLine(ProcessCommand("Math.PI").ToString()) 'Displays 3.14159265358979
        Console.WriteLine(ProcessCommand("Math.Abs(-22)").ToString()) 'Displays 22
        Console.WriteLine(ProcessCommand("3-4+6+7+22/3+66*(55)").ToString()) 'Displays 3649.333333333333333333 
    End Sub

End Module

Ciao, vedi se questo codice va bene:

    Public Class Form1
    Dim testo As String
    Dim n1 As String
    Dim n2 As String
    Dim somma As Double

    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
        If TextBox1.Text.Contains("+") Then
            n1 = TextBox1.Text.Split("+")(0)
            n2 = TextBox1.Text.Split("+")(1)
            somma = Convert.ToDouble(n1) + Convert.ToDouble(n2)
            testo = TextBox1.Text + "=" + somma.ToString()
        End If
        MsgBox(testo)

    End Sub
End Class

io l'ho provato e scrivendo "4+10" mi ha dato come risultato "14"

Grazie mille a tutti