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is it possible to access properties by name, which is a variable?

Sorry if this is asked and answered, I searched but think I don't know the vocabulary to find the answer. Researched reflection but that doesn't seem to be the answer here? I'm a novice obviously. I'm trying/making minor contributions to a mod for the new Battletech game.
I've got this Dictionary and would like to use its keys to set properties as in the foreach below. I don't know if this is at compile or runtime, my guess is compile time...
I put *limb* in as pseudo-code for how I'm imagining it might work. The property mechDef.Head is an object of type LocationLoadoutDef with its property CurrentInternalStructure being float.
Hope that makes sense!
Much obliged for any assistance.
public class Settings {
public readonly Dictionary<string, bool> LimbRepair = new Dictionary<string, bool> {
{ "Head", false },
{ "LeftArm", false },
{ "RightArm", false },
{ "CenterTorso", false },
{ "LeftTorso", false },
{ "RightTorso", false },
{ "LeftLeg", false },
{ "RightLeg", false },
};
}
MechDef mechDef = new MechDef
(__instance.DataManager.MechDefs.Get(id), __instance.GenerateSimGameUID());
foreach (string limb in settings.LimbRepair.Keys) {
if (!settings.LimbRepair[limb]) {
mechDef.*limb*.CurrentInternalStructure = Math.Max
(1f, mechDef.*limb*.CurrentInternalStructure * (float)rng.NextDouble());
}

You can do it with Reflection, but....
This is quite easy to do with Reflection, and you'll probably get a couple answers on here that show you how, but since you are writing a game, I'm guessing you want the best performance possible, and Reflection isn't always going to give you that.
Below is a solution that requires no reflection but still allows you to use the loop structure you want. It just requires a little bit of setup when you create the object, then you can access your properties as if they were in a dictionary.
Solution: Use a dictionary of delegates to map the properties
First we need to write a utility class that represents a property. Since properties can be different types, this is a generic class with a type argument.
class PropertyWrapper<T>
{
private readonly Func<T> _getter;
private readonly Action<T> _setter;
public PropertyWrapper(Func<T> getter, Action<T> setter)
{
_getter = getter;
_setter = setter;
}
public T Value
{
get
{
return _getter();
}
set
{
_setter(value);
}
}
}
The idea behind this class is that you create it to represent any property you want, and call its methods to read and set the property. The class knows how to read and set the property because you tell it how, when you construct it, by passing it a short lambda expression that does the work.
This utility will allow you to put all the properties that represent limbs into a dictionary. Then you can look them up by string, just like your settings. So for example your MechDefinition might look like this:
class MechDef
{
public Limb Head { get; set; }
public Limb LeftArm { get; set; }
public Limb RightArm { get; set; }
public Limb LeftTorso { get; set; }
public Limb RightTorso { get; set; }
public Limb CenterTorso { get; set; }
public Limb RightLeg { get; set; }
public Limb LeftLeg { get; set; }
private readonly Dictionary<string, PropertyWrapper<Limb>> Properties;
public MechDef()
{
Properties = new Dictionary<string, PropertyWrapper<Limb>>
{
{"Head", new PropertyWrapper<Limb>( () => Head, v => Head = v ) },
{"LeftArm", new PropertyWrapper<Limb>( () => LeftArm, v => LeftArm = v ) },
{"RightArm", new PropertyWrapper<Limb>( () => RightArm, v => RightArm = v ) },
{"CenterTorso",new PropertyWrapper<Limb>( () => CenterTorso, v => CenterTorso = v )},
{"RightTorso", new PropertyWrapper<Limb>( () => RightTorso, v => RightTorso = v ) },
{"LeftTorso", new PropertyWrapper<Limb>( () => LeftTorso, v => LeftTorso = v ) },
{"RightLeg", new PropertyWrapper<Limb>( () => RightLeg, v => RightLeg = v ) },
{"LeftLeg", new PropertyWrapper<Limb>( () => LeftLeg, v => LeftLeg = v ) }
};
foreach (var property in Properties.Values) property.Value = new Limb();
}
public Limb this[string name]
{
get
{
return Properties[name].Value;
}
set
{
Properties[name].Value = value;
}
}
}
Yes, there is a bit of setup there, but it's all in one place, and it only executes once, when you instantiate the MechDef. Now you can access all of the limbs by string:
foreach (var pair in settings.LimbRepair)
{
if (pair.Value != false) continue;
var limb = mechDef[pair.Key];
limb.CurrentInternalStructure = Math.Max
(
1.0F,
limb.CurrentInternalStructure * (float)rng.NextDouble()
);
}
Link to DotNetFiddle example

You can create a DynamicObject to create your own dynamic Dictionary, See the explanation here
Assume that you want to provide alternative syntax for accessing
values in a dictionary, so that instead of writing
sampleDictionary["Text"] = "Sample text", you can write
sampleDictionary.Text = "Sample text".
This is the example from the same MSDN article above:
public class DynamicDictionary : DynamicObject
{
// The inner dictionary
Dictionary<string, object> dictionary = new Dictionary<string, object>();
public int Count
{
get { return dictionary.Count; }
}
// If you try to get a value of a property not defined
// in the class, this method is called.
public override bool TryGetMember(GetMemberBinder binder, out object result)
{
// Converting the property name to lowercase so
// that property names become case-insensitive.
string name = binder.Name.ToLower();
// If the property name is found in a dictionary, set the result parameter
// to the property value and return true. Otherwise, return false.
return dictionary.TryGetValue(name, out result);
}
// If you try to set a value of a property that is not
// defined in the class, this method is called.
public override bool TrySetMember(SetMemberBinder binder, object value)
{
// Converting the property name to lowercase so that
// property names become case-insensitive.
dictionary[binder.Name.ToLower()] = value;
// You can always add a value to a dictionary, so this method always returns true.
return true;
}
}
And this is how you can use your DynamicDictionary:
dynamic person = new DynamicDictionary();
// Adding new dynamic properties. The TrySetMember method is called.
person.FirstName = "Ellen";
person.LastName = "Adams";

Reflection is one way to get at it. https://stackoverflow.com/a/1954663/83250 actually answers this perfectly. I would however restructure your data so the mechDef object is another dictionary but if you must keep it like your question asks, this will work:
void Main()
{
Dictionary<string, bool> limbRepair = new Dictionary<string, bool>
{
{ "Head", false },
{ "LeftArm", false },
{ "RightArm", false },
// Etc.
};
MechDefinition mechDef = new MechDefinition();
List<Limb> limbs = new List<Limb>();
foreach (KeyValuePair<string, bool> limbsToRepair in limbRepair.Where(x => !x.Value))
{
Limb limb = mechDef.GetPropValue<Limb>(limbsToRepair.Key);
limb.CurrentInternalStructure = 9001;
}
}
public class MechDefinition
{
public MechDefinition()
{
Head = new Limb
{
Id = Guid.NewGuid(),
DateAdded = DateTime.Parse("2018-01-01"),
Name = "Main Head",
CurrentInternalStructure = 8675309
};
}
public Guid Id { get; set; }
public string Name { get; set; }
public int CurrentInternalStructure { get; set; }
public Limb Head { get; set; } = new Limb();
public Limb LeftArm { get; set; } = new Limb();
public Limb RightArm { get; set; } = new Limb();
// etc...
}
public class Limb
{
public Guid Id { get; set; }
public string Name { get; set; }
public DateTime DateAdded { get; set; }
public int CurrentInternalStructure { get; set; }
public bool IsDisabled { get; set; }
}
public static class ReflectionHelpers
{
public static object GetPropValue(this object obj, string name)
{
foreach (string part in name.Split('.'))
{
if (obj == null) { return null; }
Type type = obj.GetType();
PropertyInfo info = type.GetProperty(part);
if (info == null) { return null; }
obj = info.GetValue(obj, null);
}
return obj;
}
public static T GetPropValue<T>(this object obj, string name)
{
object retval = GetPropValue(obj, name);
if (retval == null) { return default(T); }
// throws InvalidCastException if types are incompatible
return (T)retval;
}
}
Be aware that reflection is a very costly operation. If you are dealing with large sets of data, it will be very inefficient. Take a look at https://stackoverflow.com/a/7478557/83250 for a performance overview.
Also code-wise, I prefer to stay away from dynamic and reflection altogether. Reflection has its perks when you need to access a property attribute and dynamic is great if you don't have a strongly typed object. With that said, C# is a strongly typed language and should be treated as such whenever possible. By restructuring your mechDef as a Dictionary<string, Limb> object or something similar you will have a more efficient application.

If I understand correctly, You have something like this:
class LocationLoadoutDef
{
public LocationLoadoutDef()
{
Head = new Prop();
LeftArm = new Prop();
RightArm = new Prop();
CenterTorso = new Prop();
LeftTorso = new Prop();
RightTorso = new Prop();
LeftLeg = new Prop();
RightLeg = new Prop();
}
public Prop Head { get; set; }
public Prop LeftArm { get; set; }
public Prop RightArm { get; set; }
public Prop CenterTorso { get; set; }
public Prop LeftTorso { get; set; }
public Prop RightTorso { get; set; }
public Prop LeftLeg { get; set; }
public Prop RightLeg { get; set; }
...
}
class Prop
{
public float CurrentInternalStructure { get; set; }
...
}
So you can use reflection getting the type of the object and the property.
This is an example based on your pseudocode:
// your instance of LocationLoadoutDef
var mechDef = new LocationLoadoutDef();
//For reflection you need obtain the type
Type mechType = mechDef.GetType();
// loop your Dictionary
foreach (string limb in LimbRepair.Keys)
{
// If the property is false in the dictionary and the type has a property with that name
if (!LimbRepair[limb] && mechType.GetProperties().Any(p => p.Name == limb))
{
// Obtain the instance of the property
var property = mechType.GetProperty(limb).GetValue(mechDef) ;
// Get the property type
Type propertyType = property.GetType();
// If the property has a property CurrentInternalStructure
if (propertyType.GetProperties().Any(p => p.Name == "CurrentInternalStructure"))
{
// Obtain the current value for CurrentInternalStructure
var currentValue = propertyType.GetProperty("CurrentInternalStructure").GetValue(property);
// calculate the new value (I don't know what is rng)
var newValue = 1f ; //Math.Max(1f, (float)currentValue * (float)rng.NextDouble());
// set de value in the property
propertyType.GetProperty("CurrentInternalStructure").SetValue(property, newValue);
}
}
}

You can always create classic and working if .. else or switch.
Or create dictionary with function to update correct property
public class Repair
{
public bool Active { get; set; }
public Action<MechDef> Update { get; set; }
}
public class Settings
{
public readonly Dictionary<string, Repair> LimbRepair =
new Dictionary<string, bool> {
{
"Head",
new Repair { Active = false, mechDef => mechDef.Head.CurrentInternalStructure = yourFunctionForHead }
},
{
"LeftArm",
new Repair { Active = false, mechDef => mechDef.LeftArm.CurrentInternalStructure = yourFunctionForLeftArm }
},
// ... and so on
};
}
Then in the loop you will call correct update action, become much cleaner to use settings class with benefits of strong types and compiler help which prevent dynamic runtime errors
var updates = settings.LimbRepair.Where(pair => pair.Value.Active == false)
.Select(pair => pair.Value);
foreach (var repair in updates)
{
repair.Update();
}

Reflection to get List<object> data

I'm trying to loop through a DetailClass objects inside a List using reflection just like for string fields, but I can't figure out how.
class DetailClass
{
public string FieldDetail1 { get; set; }
public string FieldDetail2 { get; set; }
public string FieldDetail3 { get; set; }
}
class SomeClass
{
public string Field1 { get; set; }
public string Field2 { get; set; }
public string Field3 { get; set; }
public List<DetailClass> Artikli { get; set; }
}
private static PropertyInfo[] GetProperties(object obj)
{
return obj.GetType().GetProperties();
}
var myData = new SomeClass();
var prop = GetProperties(myData);
foreach (var item in prop)
{
if (item.PropertyType == typeof(string))
{
var name = item.Name,
var value = item.GetValue(myData).ToString()));
}
//how to get name and value for data inside List<DetailClass>?
}

You were trying to enumerate properties of the parent class
GetValue needs the a reference to the class you are dealing with
Code
var myData = new SomeClass();
myData.Artikli = new List<DetailClass>() { new DetailClass() { FieldDetail1 = "asd", FieldDetail2 = "sdfd", FieldDetail3 = "sdfsg" } };
foreach (var obj in myData.Artikli)
{
foreach (var item in obj.GetType().GetProperties())
{
if (item.PropertyType == typeof(string))
{
var name = item.Name;
var val = item.GetValue(obj);
Console.WriteLine(name + ", " + val);
}
}
}
Demo Here
Additional Resources
PropertyInfo.GetValue Method (Object)
Returns the property value of a specified object.
Parameters
obj
Type: System.Object
The object whose property value will be returned.

You can use your method recursively to get inside all layer of properties
You can check if
item.PropertyType.GetInterfaces().Contains(typeof(IEnumerable))
and if true cast (IEnumerable)item.GetValue(myData) and iterate on the result
recursively.

Just like TheDude answered, you can use a recursive method like so;
private void Recursion(object obj)
{
var props = GetProperties(obj);
foreach (var item in props)
{
if (item.PropertyType == typeof(string))
{
var name = item.Name;
var value = item.GetValue(obj)?.ToString();
}
else if (item.PropertyType == typeof(List<DetailClass>))
{
var test = (List<DetailClass>) item.GetValue(obj);
foreach (var t in test)
{
Recursion(t);
}
}
}
}
And do whatever you want with the name and values in the list.

How to correctly use Expression Trees on properties (without reflection)

Objective: process an object and if the object implements an expected type, I want to change a specific property value (this part is working fine), and I also would like to apply the same logic to all property lists (that I explicit point) that are of the same expected type.
I have the following code:
public abstract class BaseObject
{
public int Id { get; set; }
}
public class Father : BaseObject
{
public DateTime CreatedOn { get; set; }
public string Name { get; set; }
public IEnumerable<ChildA> Children1 { get; set; }
public IEnumerable<ChildB> Children2 { get; set; }
public IEnumerable<ChildA> Children3 { get; set; }
public IEnumerable<ChildB> Children4 { get; set; }
}
public class ChildA : BaseObject
{
public int Val1 { get; set; }
}
public class ChildB : BaseObject
{
public string Name { get; set; }
public int Total { get; set; }
}
I want to process an object by applying some changes on a specific property on the target object and on all property children that I explicit say:
public void Start()
{
var listA = new List<ChildA> { new ChildA { Id = 1, Val1 = 1 }, new ChildA { Id = 2, Val1 = 2 } };
var listB = new List<ChildB> { new ChildB { Id = 1, Name = "1", Total = 1 } };
var obj = new Father { Id = 1, CreatedOn = DateTime.Now, Name = "F1", ChildrenA = listA, ChildrenB = listB };
// I explicit tell to process only 2 of the 4 lists....
ProcessObj(obj, x => new object[] { x.Children1, x.Children2 });
}
I was able to write this function:
public void ProcessObj<T>(T obj, Expression<Func<T, object[]>> includes = null)
{
var objBaseObject = obj as BaseObject;
if (objBaseObject == null) return;
// Here I change the ID - add 100 just as an example....
objBaseObject.Id = objBaseObject.Id + 100;
if (includes == null) return;
var array = includes.Body as NewArrayExpression;
if (array == null) return;
var exps = ((IEnumerable<object>)array.Expressions).ToArray();
for (var i = 0; i < exps.Count(); i++)
{
var name = ((MemberExpression)exps[i]).Member.Name;
var childProperty = obj.GetType().GetProperties(
BindingFlags.Public | BindingFlags.Instance
).FirstOrDefault(prop => prop.Name == name);
if (childProperty == null) continue;
// NOT correct because I think I am getting a copy of the object
// and not pointing to the object in memory (by reference)
var childList = childProperty.GetValue(obj);
// TODO: loop on the list and apply the same logic as the father....
// change the ID field....
}
}
In this prototype I started writing reflection, but I really would like to avoid it if possible....
How can I do this???

Maybe I'm missing something, but it seems like you're complicating the problem by using expression trees. Can you just not use a regular Action and Func delegates to do this? Why do they need to be expression trees? Here's an example just using delegates:
public void ProcessObj<T>(T obj, Func<T, IEnumerable<object>> includes) {
var objBaseObject = obj as BaseObject;
if (objBaseObject == null) return;
// Create a reusable action to use on both the parent and the children
Action<BaseObject> action = x => x.Id += 100;
// Run the action against the root object
action(objBaseObject);
// Get the includes by just invoking the delegate. No need for trees.
var includes = includes(obj);
// Loop over each item in each collection. If the types then invoke the same action that we used on the root.
foreach(IEnumerable<object> include in includes)
{
foreach(object item in include)
{
var childBaseObject = item as BaseObject;
if(childBaseObject != null)
{
action(childBaseObject);
}
}
}
}
Useable just like before:
ProcessObj(obj, x => new object[] { x.Children1, x.Children2 });
No expression trees and no reflection, just regular delegate lambdas.
Hope that helps

Nested List Order In C#

I have a custom list called ServiceFormFields and it has a List property named ChildrenTables.
I want to order descending by ChildrenTables' names
var fields = activeForm.ServiceFormFields.OrderBy (o =>
o.ChildrenTables.OrderBy(c=>c)).ToList();
but it does not work.
I want to order ServiceFormFields list according to its children. Maybe I should do with GroupBy..
So, for example...
ServiceFormFields has FieldName property.. and Children is a List of String
FieldName = Matter, Children = Version
FieldName = Client, Children = Matter
FieldName = Status, Children = Null
FieldName = Version, Children = Null (but has parents, it is Matter)
so and I want to order like:
2,1,3,4
because Client is the on highest level, second is Matter, third one is Version because Matter is its parent, and final is Status, because it does not have any dependency.
Edit: This is structure of the class
public class ServiceForm
{
public List<ServiceFormField> ServiceFormFields { get; set; }
public string Id { get; set; }
public bool IsDefaultPrimary { get; set; }
public string Name { get; set; }
public string Title { get; set; }
public string Type { get; set; }
}
public class ServiceFormField
{
public FormProperty FormField {get;set;}
public bool IsVisible { get;set;}
public List<string> ParentTables { get; set; }
public bool HasChildren { get; set; }
public List<string> ChildrenTables { get; set; }
}
public partial class FormProperty
{
private string NameField;
private string SQLInfoField;
...
}
NameField contains Client, Matter, Version..

I don't know if this is what you want, but here's a solution with the least bits of code needed.
I just transformed all the Childrens into a single string, and then the order by compares against them.
This is certainly not the most performance-wise solution, if this matters.
here's a sample:
static void Main(string[] args)
{
ServiceForm sf = new ServiceForm();
sf.ServiceFormFields = new List<ServiceFormField>
{
new ServiceFormField { ChildrenTables = new List<string> { "a", "b", "c"}},
new ServiceFormField { ChildrenTables = new List<string> { "tra la la", "xxx"}},
new ServiceFormField { ChildrenTables = new List<string> { "TTTTT" }},
new ServiceFormField { ChildrenTables = new List<string> { "123455", "8157125", "1763123"}},
new ServiceFormField { ChildrenTables = new List<string> { " ", " ", " ", " "}}
};
var ordered= sf.ServiceFormFields.OrderByDescending(f => string.Join(",", f.ChildrenTables)).ToList();
foreach(ServiceFormField sff in ordered)
{
foreach(string s in sff.ChildrenTables)
{
Console.WriteLine(s);
}
}
}
Output:

There are two ways, first you can use the List.Sort function with the signature Comparison like:
activeForm.ServiceFormFields.Sort(new Comparison<ServiceFormField>((e1,e2)=>Compare(e1, e2)));
private static int Compare(ServiceFormField e1, ServiceFormField e2)
{
//Do your logic here
}
in this case you will have an inplace sort.
or use the linq orderby function with the signature to KeySelector, an IComparer and implement an IComparer like that
var result = activeForm.ServiceFormFields.OrderBy(e => e, new ServiceFormFieldComparer());
public class ServiceFormFieldComparer : IComparer<ServiceFormField>
{
private int Compare(ServiceFormField e1, ServiceFormField e2)
{
//Your logic here
}
}
in this case you will have an ordered list returned to you

Build hierarchy from strings C#

I have a collection of strings:
"Alberton;Johannesburg"
"Allendale;Phoenix"
"Brackenhurst;Alberton"
"Cape Town;"
"Durban;"
"Johannesburg;"
"Mayville;Durban"
"Phoenix;Durban"
"Sandton;Johannesburg"
that I want to structure into a hierarchical structure in the fastest possible manner, like:
Johannesburg
Alberton
Brackenhurst
Sandton
Cape Town
Durban
Phoenix
Allandale
Mayville
Currently I have nested for loops and checks, but was hoping I could achieve this with a single LAMBDA query?
The above mentioned strings are in a List.

I prepared lambda-like solution, but you should really think if it's more readable/efficient then your current one:
Helper Extension Method:
public static class ChildrenGroupExtensions
{
public static List<CityInfo> GetChildren(this IEnumerable<IGrouping<string, City>> source, string parentName)
{
var cities = source.SingleOrDefault(g => g.Key == parentName);
if (cities == null)
return new List<CityInfo>();
return cities.Select(c => new CityInfo { Name = c.Name, Children = source.GetChildren(c.Name) }).ToList();
}
}
Helper Classes:
public class City
{
public string Name { get; set; }
public string Parent { get; set; }
}
public class CityInfo
{
public string Name { get; set; }
public List<CityInfo> Children { get; set; }
}
Usage:
var groups = (from i in items
let s = i.Split(new[] { ';' })
select new City { Name = s[0], Parent = s[1] }).GroupBy(e => e.Parent);
var root = groups.GetChildren(string.Empty);
Where items is your List<string>
You can look the results with simple helper method like that one:
private static void PrintTree(List<CityInfo> source, int level)
{
if (source != null)
{
source.ForEach(c =>
{
Enumerable.Range(1, level).ToList().ForEach(i => Console.Write("\t"));
Console.WriteLine(c.Name);
PrintTree(c.Children, level + 1);
});
}
}
And the results are:
Cape Town
Durban
Mayville
Phoenix
Allendale
Johannesburg
Alberton
Brackenhurst
Sandton

You haven't specified any specific data structure so I just used a class called Area with a list of children of itself. Also, it's in 2 lines of linq. There is also no check to see if an area is a child of 2 separate parents as the code is. Here's the code for the test I used(Relevant lines in-between the equals comments):
[TestFixture]
public class CitiesTest
{
[Test]
public void Test()
{
var strings = new List<string>
{
"Alberton;Johannesburg",
"Allendale;Phoenix",
"Brackenhurst;Alberton",
"Cape Town;",
"Durban;",
"Johannesburg;",
"Mayville;Durban",
"Phoenix;Durban",
"Sandton;Johannesburg"
};
//===================================================
var allAreas = strings.SelectMany(x=>x.Split(';')).Where(x=>!string.IsNullOrWhiteSpace(x)).Distinct().ToDictionary(x=>x, x=>new Area{Name = x});
strings.ForEach(area =>
{
var areas = area.Split(';');
if (string.IsNullOrWhiteSpace(areas[1]))
return;
var childArea = allAreas[areas[0]];
if (!allAreas[areas[1]].Children.Contains(childArea))
allAreas[areas[1]].Children.Add(childArea);
childArea.IsParent = false;
});
var result = allAreas.Select(x=>x.Value).Where(x => x.IsParent);
//===================================================
}
public class Area
{
public string Name;
public bool IsParent;
public List<Area> Children { get; set; }
public Area()
{
Children = new List<Area>();
IsParent = true;
}
}
}