How to convert the list containing different datatypes into a single string?

I have list containg float ,int and string values.How to convert all those values into a single string.

List<HandleValues> SaveValues = new List<HandleValues>();
  SaveValues.Add(new HandleValues(id,modname,Positionx,Positiony,Positionz,Rotationw,Rotationx,Rotationy,Rotationz));

//How to get all those values inside the SaveValues list as a single string so that I can convert it into JSON
string Alldetails=  SaveValues.(???????)

using System.Collections;
using System.Collections.Generic;

public class HandleValues 
    public int Id  { set; get; }
    public string Modelname { set; get; }
    public float Posx { set; get; }
    public float Posy { set; get; }
    public float Posz { set; get; }

    public float Rotw { set; get; }
    public float Rotx { set; get; }
    public float Roty { set; get; }
    public float Rotz { set; get; }

    public HandleValues(int id,string modelname,float posx,float posy,float posz,float rotw,float rotx,float roty,float rotz)
        this.Id = id;
        this.Modelname = modelname;
        this.Posx = posx;
        this.Posy = posy;
        this.Posz = posz;

        this.Rotw = rotw;
        this.Rotx = rotx;
        this.Roty = roty;
        this.Rotz = rotz;


just create a method inside that class

public override string ToString()
    return string.Concat(Id, Modelname, Posx, Posy, Posz, Rotw, Rotx, Roty, Rotz);

when you call tostring will give yuou that string so you can iterate over the list.

Convert your list to an array named, say, saveDetailsArraythen to convert it to JSON it’s simply:

string jsonString = JsonUtility.ToJson(saveDetailsArray, true);

that’ll get you a prettified JSON string with all the data… you might need to create a new serializable class for the array

public class YourNewArrayClass
    public HandleValues[] YourDetailsArray;

public YourNewArrayClass YourDetails;

string jsonString = JsonUtility.ToJson(YourDetails, true);