Below is a sample code snippet which demonstrates on how to convert all strings in a list to upper case using LINQ in C#.
Convert All Strings in a List to Upper Case using LINQ in C#
using System;
using System.Collections.Generic;
using System.Linq;
namespace AbundantCode
{
internal class Program
{
//Convert All Strings in a List to Upper Case using LINQ in C#
private static void Main(string[] args)
{
List<string> Names = new List<string>();
Names.Add("Abundantcode");
Names.Add("Programming");
Names.Add("Websites");
Names.Add("Coding");
Names.Add("Technologies");
Names.Add("USA");
Names.Add("C#");
Names.Add(".NET");
var result = Names.Select(m => m.ToUpper());
foreach (var item in result)
Console.WriteLine(item);
Console.ReadLine();
}
}
}Output

you can use “ConvertAll”
myList = myList.ConvertAll(d => d.ToUpper());