Use the Append() method to append two strings, an int, and a bool to StringBuilder : StringBuilder « String « C# / CSharp Tutorial

1. C# / CSharp Tutorial
2. String
3. StringBuilder

using System;
using System.Text;

class MainClass
{
  public static void Main()
  {
    StringBuilder myStringBuilder = new StringBuilder();
    
    myStringBuilder.Append("myString");
    myStringBuilder.Append(" ... ");
    int myInt = 1234;
    myStringBuilder.Append(myInt);
    bool myBool = true;
    myStringBuilder.Append(myBool);


    Console.WriteLine(myStringBuilder);
  }
}

myString ... 1234True