Question

I’m an IronPython novice and would like some help. I have a windows form that I have created in Visual Basic 2010 Express, which contains two text-boxes (‘txtNumber‘ and ‘txtResult‘) and a button (‘btnSquare‘). What I want to do is be able to call the below Python script (‘Square.py‘) on clicking the button on the form;

class SquarePython:

    def __init__(self, number):

        self.sq = number*number

This script should square the number that is input in to ‘txtNumber‘ and then output the result in to ‘txtResult‘. I know this is almost too simple, but I just need to know the basics. Here’s what I have so far in my VB code;

Imports Microsoft.Scripting.Hosting
Imports IronPython.Hosting
Imports IronPython.Runtime.Types

Public Class Square

    Private Sub btnSquare_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnSquare.Click

        Dim runtime As ScriptRuntime = Python.CreateRuntime

        Dim scope As ScriptScope = runtime.ExecuteFile("Square.py")

    End Sub

End Class

Thanks in advance.

Answer 1

I will give an answer in C#, if you don’t mind. But anyway it is very similar to VB version. For your code accessing SquarePython is very simple

ScriptEngine py = Python.CreateEngine();

ScriptScope scope = py.ExecuteFile("Square.py");

dynamic square = scope.GetVariable("SquarePython");

int result = (int)square(5);

Console.WriteLine(result.sq); //prints 25 as you might expected

But for simplicity, I would modify python code a little bit, like this

class SquarePython:
    def Square(self, number):
        return number * number

So that you don’t have to create an object each time you compute. Code that retrieve variable and call method to square is given below:

ScriptEngine py = Python.CreateEngine();

ScriptScope scope = py.ExecuteFile("Square.py");
//get variable and then create and object. Could be stored somewhere between computations
dynamic squareInstance = scope.GetVariable("SquarePython")(); 

int result = (int) squareInstance.Square(5);

Console.WriteLine(result);

Notes: see VB.Net equivalent for C# ‘dynamic’ if you need to convert dynamic keyword to VB.NET