Knowledgebase

This post describes how to call an action in Outsystems, based on a given eSpace name and action name.

Lets says you want the user to select a action name from a dropdownlist and execute this action, then you can create a big switch statement to call the actions supplied in the dropdownlist, but if you don’t want to change this switch statement each time a new action is added to the list, then you have to create an Outsystems actions and write some C# code, to dynamically execute the action based on a given eSpace name and action name.

Extension

Visual Studio

C# code

namespace OutSystems.NssDynamicExtension {

using System;
using System.Collections;
using System.Data;
using OutSystems.HubEdition.RuntimePlatform;
using GotDotNet.ApplicationBlocks;
using System.Text;
using System.Linq;
using System.Reflection;

public class CssDynamicExtension: IssDynamicExtension {

/// <summary>
/// 
/// </summary>
/// <param name="ssresult"></param>
/// <param name="sseSpaceName"></param>
/// <param name="ssactionName"></param>
public void MssInvokeAction(out string ssresult, string sseSpaceName, string ssactionName) {
    ssresult = string.Empty;
    var messages = new StringBuilder(string.Empty);

    try
    {

        // Get all assemblies in current AppDomain.
        AppDomain currentDomain = AppDomain.CurrentDomain;
        Assembly[] assemblies = currentDomain.GetAssemblies();

        // Log all assemblynames.
        assemblies.ToList()
            .OrderBy(x => x.FullName).ToList()
            .ForEach(x => { messages.AppendLine(x.GetName().Name); });

        // Get eSpace assembly.
        Assembly eSpaceAssemlby = assemblies.ToList()
                    .First(x => x.GetName().Name.Equals(sseSpaceName, StringComparison.InvariantCultureIgnoreCase));

        // Get assembly that contians the "HeContext" type.
        Assembly runtimePlatform = assemblies.ToList()
                .First(x => x.GetName().Name.Equals("OutSystems.HubEdition.RuntimePlatform"));

        // Get the type that contains all actions from an eSpace.
        Type actionsType = eSpaceAssemlby.GetType(string.Format("ss{0}.Actions", sseSpaceName));

        // Get "HeContext" type (curent HttpContext object).
        Type contextType = runtimePlatform.GetType("OutSystems.HubEdition.RuntimePlatform.HeContext");

        // Create an instance of the "HeContext" type.
        object contextInstance = Activator.CreateInstance(contextType);

        // Invoke the given action and supply as first parameter the "HeContext" (curent HttpContext) object.
        actionsType.InvokeMember(string.Format("Action{0}", ssactionName), 
                                BindingFlags.InvokeMethod | BindingFlags.Static | BindingFlags.Public, 
                                null, null, new object[] { contextInstance });
    }
    catch (Exception ex)
    {
        messages.AppendLine(ex.ToString());
    }

    ssresult = messages.ToString();
} // MssInvokeAction

} // CssDynamicExtension

} // OutSystems.NssDynamicExtension

Use the action in Outsystems

Result

The action that was dynamically invoked, inserted a record in the database and I could see this record was created, so everything worked just fine.

So instead of:

My code now looks like this:

Sometimes, reflection is your friend .