ardupilot/Configurator/Configurator.Net/PresentationModels/VmBase.cs

using System;
using System.Collections.Generic;

namespace ArducopterConfigurator
{

    public interface ISupportsExternalInvokedInpc
    {
        void FirePropertyChanged(string propName);
    }


    /// <summary>
    /// Helper class that takes an update from the APM and writes to properties of an object using reflection
    /// </summary>
    /// <remarks>
    /// The APM gives us a stream of values .eg 4.0,5.2,3.4 etc
    /// They are in a certain known order, e.g pitch P, pitch I, pitch D... etc
    /// 
    /// instead of having specific value assignment logic in every class to pick
    /// apart the update and populate properties, this guy will Set the properties
    /// in the correct order. All the interested class needs to provide is the
    /// list of property names in the same order as the update from the APMwl
    /// </remarks>
    public static class PropertyHelper
    {
        // Common method for creating the update data
        // sentence sent to APM is the commandChar followed by the property
        // vals in the correct order, seperated by semicolons
        public static string ComposePropValuesWithCommand(object obj, IList<string> propertiesToUpdate, string commandChar)
        {
            var strings = new string[propertiesToUpdate.Count];
            for (int i = 0; i < propertiesToUpdate.Count; i++)
            {
                var prop = obj.GetType().GetProperty(propertiesToUpdate[i]);

                if (prop.PropertyType == typeof(bool))
                    strings[i] = ((bool)prop.GetValue(obj, null)) ? "1" : "0";
                else
                    strings[i] =  prop.GetValue(obj, null).ToString(); // Todo: culture aware strings for floats etc
            }

            return commandChar + string.Join(";", strings);
        }

        // Common method for populating properties, using a hardcoded 
        // property update order, and reflection to get the property type
        public static void PopulatePropsFromUpdate(ISupportsExternalInvokedInpc obj,IList<string> propertiesToUpdate, string strRx, bool fireInpc)
        {
            var strs = strRx.Split(',');

            if (propertiesToUpdate.Count != strs.Length)
            {
                Console.WriteLine("Processing update with " + strs.Length
                                  + " values, but have " + propertiesToUpdate.Count
                                  + " properties to populate. Ignoring this update");
                return;
            }

            for (int i = 0; i < propertiesToUpdate.Count; i++)
            {
                var prop = obj.GetType().GetProperty(propertiesToUpdate[i]);
                var s = strs[i];
                object value = null;

                if (prop == null)
                {
                    Console.WriteLine("Trying to set non existant property: " + propertiesToUpdate[i]);
                    break;
                }

                if (prop.PropertyType == typeof(float))
                {
                    float val;
                    if (!float.TryParse(s, out val))
                    {
                        Console.WriteLine("Error parsing float: '{0}', VM: {1}" ,s, obj);
                        break;
                    }
                    value = val;
                }
                if (prop.PropertyType == typeof(bool))
                {
                    float val;
                    if (!float.TryParse(s, out val))
                    {
                        Console.WriteLine("Error parsing float (bool): '{0}', VM: {1}" ,s, obj);
                        break;
                    }
                    value = val != 0.0;
                }

                if (prop.PropertyType == typeof(int))
                {
                    int val;
                    if (!int.TryParse(s, out val))
                    {
                        Console.WriteLine("Error parsing int: '{0}', VM: {1}"  ,s, obj);
                        break;
                    }
                    value = val;
                }

                prop.SetValue(obj, value, null);
                
                if (fireInpc)
                    obj.FirePropertyChanged(propertiesToUpdate[i]);
            }
        }

    }
}