Replace List of string into an existing string C#?

Question

I Have a class and inside this class a string variable. I want to replace all the occurrences of specific words inside this variable with the List<string> of string.

using System;
using System.Collections.Generic;
public class HelloWorld
{
    List<string> lst = new List<string>();
    lst.Add("Sunil");
    lst.Add("Sunil123");
    lst.Add("Sunil@123");
    string smsTemplate = "Dear {#var#},You have successfully register to online system please login to system by below credentials,User Name : {#var#}   Password : {#var#}  SunSoft, DeshlahreMiniGraden";
    string searchStr = "{#var#}";
}

So the output of this "smsTemplate" variable should be replaced with the list of strings provided. For example "Sunil" should be placed at the position of first "{#var#}","Sunil123" should be replaced at the position of second "{#var#}" and so on.

Answer 1

You could do it in a quite straight-forward manner by splitting the smsTemplate on the searchStr and building a new string by appending the split parts from smsTemplate and each item in lst in an alternating manner. For instance:

List<string> lst = new List<string>();

lst.Add("Sunil");
lst.Add("Sunil123");
lst.Add("Sunil@123");

string smsTemplate = "Dear {#var#},You have successfully register to online system please login to system by below credentials,User Name : {#var#}   Password : {#var#}  SunSoft, DeshlahreMiniGraden";
string searchStr = "{#var#}";

var templateParts = smsTemplate.Split(searchStr);

// In case the {#var#} count in smsTemplate differs from the lst count
var replacementCount = Math.Min(lst.Count, templateParts.Length - 1);

var builder = new StringBuilder(templateParts[0]);

for (var i = 0; i < replacementCount; i++)
{
    builder.Append(lst[i]);
    builder.Append(templateParts[i + 1]);
}

var sms = builder.ToString();

A fiddle is found here.