Fill variable if MemberInfo name is same as a string

Question

I'm trying to build a fast system to fill variables on classes from a text file. I surely can do this in a simple way by reading certain lines on a text file, but I'm trying to do this dynamic as possible without the need to hardcode almost everything.

I use a static class to fill a Dictionary with key val strings that are taken from the text file (splitting each line), and I can get to the point to see if the text file have the variable names equal to the class variables names using MemberInfo, the problem is I don't know how to return back that variable as depending on the type I have to parse the string to int or float or anything else. This is what I've done so far on retrieving the text file strings:

 static public void GetVariableLine (string path, MemberInfo m) {
     
     string text = projectPath + "/" + path;
     
 using (StreamReader sr = new StreamReader(text)) {

     string line;
 
     while ((line = sr.ReadLine()) != null) {
         string[] newLine = line.Split('=');
         keyVal.Add(newLine[0], newLine[1]);
             
         foreach (MemberInfo member in m.GetType().GetMembers()) {
             if(member.Name == newLine[0])
                     Debug.Log (member.Name);
         }
             
         Debug.Log (newLine[1]);
     }
         
     sr.Close();
     keyVal.Clear();
         
     }
 }

And I call this function by the script I want the variables filled:

 void Start () {
     NFParser.GetVariableLine(file, this.GetType());
 }

So as you can see for now there are only debug logs in there, what I would like to do is to get back the variable from the dictionary for the corrisponding memberinfo name of the class, but I'm at a dead end, not even sure this is possible.

Answer 1

Firstly - I believe there is an error in your method signature. You have

 MemberInfo m

and later you're calling

 m.GetType().GetMembers()

so I guess the parameter should be actual object instance.

Anyway, if I had to implement filling an object using values from file, I would do it this way:

 static Dictionary<string, string> keyVal = new Dictionary<string, string>();
 
 static public void FillObjectDataFromFile(string path, object instance)
 {
     string text = projectPath + "/" + path;
 
     var dicPropertyInfosByName = instance.GetType().GetProperties().ToDictionary(x => x.Name);
     var dicFieldInfosByName = instance.GetType().GetFields().ToDictionary(x => x.Name);
 
     keyVal.Clear();
     using (StreamReader sr = new StreamReader(text))
     {
         string line;
 
         while ((line = sr.ReadLine()) != null)
         {
             string[] newLine = line.Split('=');
             keyVal.Add(newLine[0], newLine[1]);
         }
     }
 
     foreach (var kv in keyVal)
     {
         if (dicFieldInfosByName.ContainsKey(kv.Key))
         {
             SetFieldValue(instance, dicFieldInfosByName[kv.Key], kv.Value);
         }
         else if (dicPropertyInfosByName.ContainsKey(kv.Key))
         {
             SetPropertyValue(instance, dicPropertyInfosByName[kv.Key], kv.Value);
         }
     }
 }
 
 private static void SetFieldValue(object instance, FieldInfo fieldInfo, string value)
 {
     fieldInfo.SetValue(instance, GetConvertedValue(value, fieldInfo.FieldType));
 }
 
 private static void SetPropertyValue(object instance, PropertyInfo propertyInfo, string value)
 {
     propertyInfo.SetValue(instance, GetConvertedValue(value, propertyInfo.PropertyType), null);
 }
 
 private static object GetConvertedValue(string value, Type type)
 {
     if (type == typeof(string) || type == typeof(object))
     {
         return value;
     }
     if (type == typeof(int))
     {
         return int.Parse(value);
     }
     if (type == typeof(float))
     {
         return float.Parse(value, NumberFormatInfo.InvariantInfo);
     }
     // if conditions for other types
 
     throw new Exception("Unknown type: " + type.FullName);
 }

This is of course some basic code, because it works for public properties/fields only, and is able to convert a few types only, but I think you should be able to expand it to fit your needs.

I hope I didn't misunderstand you, but if this is not the answer you expected, please comment :)

Fill variable if MemberInfo name is same as a string

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