CSHARP

remove all text after string c#

string input = "text?here";
int index = input.LastIndexOf("?"); // Character to remove "?"
if (index > 0)
    input = input.Substring(0, index); // This will remove all text after character ?

remove all letters from string c#

// add directive at the top 
using System.Text.RegularExpressions;

string numberOnly = Regex.Replace(s, "[^0-9.]", "")