Use array from Python as method argument to .NET Framework DLL

This article shows how to pass array as an argument.

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Custom .NET Framework DLL with method accepting array

With Javonet it is possible to reference any custom .NET Framework DLL and interact with arrays declared on types defined within that module almost the same as with any other Python library.

Snippet below represents the sample code from .NET Framework DLL that has methods which return or process the arrays:

public string[] Get1DArray()
{
    return new string[] { "one", "two", "three", "four", "five" };
}

public string[,] Get2DArray()
{
    return new string[,] { { "S00", "S01" }, { "S10", "S11" } };
}

public double AddArrayElementsAndMultiply(double[] myArray, double myValue)
{
    double sum = 0;
    foreach (double element in myArray)
    {
        sum += element;
    }

    return sum * myValue;
}

With Javonet SDK it is possible to pass array as an argument to one of this method.

Pass Python array

I code in:
# use activate only once in your app
Javonet.activate("your-license-key")

# create called runtime context
called_runtime = Javonet.in_memory().clr()

# set up variables
library_path = resources_directory + '/TestClass.dll'
class_name = 'TestClass.TestClass'

# load custom library
called_runtime.load_library(library_path)

# get type from the runtime
called_runtime_type = called_runtime.get_type(class_name).execute()

# create type's instance
instance = called_runtime_type.create_instance().execute()

# get type for casting
target_type = called_runtime.get_type("System.Double[]")

# invoke instance's method
response = instance.invoke_instance_method("AddArrayElementsAndMultiply",
                                           called_runtime.cast(target_type, [12.22, 98.22, -10.44]),
                                           9.99).execute()

# get value from response
result = response.get_value()

# write result to console
print(result)

In the snippet above, addArrayElementsAndMultiply method needs array to be the first argument. Depending on called technology, the array may need to have a specific type, f. e. array of doubles. In this case, proper cast is needed before passing the array from Python.

The same operation can be performed remotely by just changing the new Runtime Context invocation from in memory to tcp that will create and interact with your .NET Framework DLL objects on any remote node, container or service that hosts Javonet Code Gateway. This way you can preserve the same logic in your application and instantly switch between monolithic and microservices architecture without the need to implement the integration layer based on web services or other remote invocation methods.

Read more about use cases and software architecture scenarios where Javonet runtime bridging technology can support your development process.

Additional references