wlwl2/csharp-teleprompter-console

Basic C# File I/O and Async Programming.

TeleprompterConsole (.NET Core 5/VSCode)

dotnet --version should be version 5 (e.g. 5.0.401).

Type in dotnet run in the VSCode terminal in the root/main folder to run the application.

Use Ctrl-C to stop the teleprompter.

This project shows:

• The basics of the .NET Core CLI
• The structure of a C# Console Application
• Console I/O
• The basics of File I/O APIs in .NET
• The basics of the Task-based Asynchronous Programming in .NET

Use VSCode.

https://docs.microsoft.com/en-us/dotnet/csharp/tutorials/console-teleprompter

Creating a new console app

1. dotnet new console
2. dotnet restore

1. Program.cs

using System;
using System.Collections.Generic;
using System.IO;
using System.Threading.Tasks;

namespace TeleprompterConsole {
    class Program {
        static void Main (string[] args) {
            RunTeleprompter().Wait();
        }

        private static async Task ShowTeleprompter (TelePrompterConfig config) {
            IEnumerable<string> words = ReadFrom("sampleQuotes.txt");
            foreach (string line in words) {
                Console.Write(line);
                if (!string.IsNullOrWhiteSpace(line)) {
                    await Task.Delay(config.DelayInMilliseconds);
                }
            }
            config.SetDone();
        }

        static IEnumerable<string> ReadFrom (string file) {
            string line;
            using (StreamReader reader = File.OpenText(file)) {
                while ((line = reader.ReadLine()) != null) {
                    string[] words = line.Split(' ');
                    int lineLength = 0;
                    foreach (string word in words) {
                        yield return word + " ";
                        lineLength += word.Length + 1;
                        if (lineLength > 70) {
                            yield return Environment.NewLine;
                            lineLength = 0;
                        }
                    }
                    yield return Environment.NewLine;
                }
            }
        }

        private static async Task GetInput (TelePrompterConfig config) {
            Action work = () => {
                do {
                    ConsoleKeyInfo key = Console.ReadKey(true);
                    if (key.KeyChar == '>') {
                        config.UpdateDelay(-10);
                    } else if (key.KeyChar == '<') {
                        config.UpdateDelay(10);
                    }
                } while (!config.Done);
            };
            await Task.Run(work);
        }

        private static async Task RunTeleprompter () {
            TelePrompterConfig config = new TelePrompterConfig();
            Task displayTask = ShowTeleprompter(config);
            Task speedTask = GetInput(config);
            await Task.WhenAny(displayTask, speedTask);
        }
    }
}

2. TeleprompterConsole.cs

using static System.Math;

namespace TeleprompterConsole {
    internal class TelePrompterConfig {
        private object lockHandle = new object();
        public int DelayInMilliseconds { get; private set; } = 200;
        public void UpdateDelay (int increment) {
            int newDelay = Min(DelayInMilliseconds + increment, 1000);
            newDelay = Max(newDelay, 20);
            lock (lockHandle) {
                DelayInMilliseconds = newDelay;
            }
        }
        public bool Done { get; private set; }
        public void SetDone () {
            Done = true;
        }
    }
}