using System;

using System.Text;

using System.Reflection;

public class Program

{

    public static void Main()

    {

        var mo = new MyObject();

        Console.WriteLine(mo);

        mo.TrimStrings();

        Console.WriteLine(mo);

    }

}

​

public class MyObject

{

    [DontTrim]

    public string A {get;set;} = "   hey man";

    public string B {get;set;} = "Hello there!      ";

    public string C {get;set;} = "Hi.";

    public string D {get;set;} = "          ";

    public int E {get;set;} = 32;

    public int F {get;set;} = 64;

    public override string ToString()

    {

        var sb = new StringBuilder();

        sb.Append(nameof(MyObject) + ": { ");

        foreach (var item in this.GetType().GetProperties(BindingFlags.Instance | BindingFlags.Public))

        {

            sb.Append("[" + item.Name + ": \"" + item?.GetValue(this, null) + "\"] ");

        }

        sb.Append("}");

        return sb.ToString();

    }

}

​

[AttributeUsage(AttributeTargets.Property, AllowMultiple = false)]

public class DontTrimAttribute : Attribute

{

}

​

public static class TrimExtension

{

    public static void TrimStrings(this object o)

    {

        foreach (var item in o?.GetType().GetProperties(BindingFlags.Public | BindingFlags.Instance))

        {

            if (!Attribute.IsDefined(item, typeof(DontTrimAttribute)) && item.PropertyType == typeof(string))

            {

                item.SetValue(o, (item.GetValue(o, null) as string)?.Trim(), null);

            }

        }

    }

}

​