Monika Lachowicz Monika Lachowicz - 1 year ago 129
C# Question

How to implement automatically checked and unchecked radio button and timer in C#?

I need to write a Windows Application in C# but I don't know how to do some things. I'm very fresh in C# Programming.

What should do my app ?

  • First step : I need to do from my radiobuttons or from something else colorful icons, these icon should random light up and I must to power off this with corresponding buttons (for exaple red radiobutton = red button).

  • Second step : There is a timer, which start counting my reflex from lit button to power off this button.

What I've done ?

  • Implemented radio buttons, button and two labels

  • Responsible for every component clicked empty methods

Which program I'm using ?

  • Visual Studio 2008 Express

What I don't know how to do ?

  • How to implement timer and set counting to check my reflex

  • How to set radio button automatically checked in random order and turn this off with other button

  • How to show in label my timer

My source code :

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Ling;
using System.Text;
using System.Windows.Forms;

namespace App{
public partial class Form1 : Form{
public Form1(){
private void label1Click(object sender, EventArgs e){
private void radioButton1_CheckedChanged(object sender, EventArgs e){

private void radioButton2_CheckedChanged(object sender, EventArgs e){

private void radioButton3_CheckedChanged(object sender, EventArgs e){

private void GreenButton_Click(object sender, EventArgs e){
GreenButton.Backcolor = Color.gray;
private void RedButton_Click(object sender, EventArgs e){
RedButton.Backcolor = Color.gray;

private void BlueButton_Click(object sender, EventArgs e){
BlueButton.Backcolor = Color.gray;
private void label2Click(object sender, EventArgs e){


I will be very thankful for every kind of help <3

Answer Source

Instead of a System.Windows.Forms.Timer, you should use a System.Diagnostics.Stopwatch to measure the reflex time.

Just create a stopwatch at class level:

private Stopwatch stopwatch = new Stopwatch();

After you light up the radio button, you start the stopwatch:


When the correct button is clicked by the user, you stop the stopwatch and get the elapsed time:

var elapsedTime = stopwatch.ElapsedMilliseconds;

Also, you should uncheck all radio buttons here:

radioButton1.Checked = false;
radioButton2.Checked = false;
radioButton3.Checked = false;

Then you can display this variable to the user by doing something like this:

<insert your label's name here>.Text = "Your time: " + elapsedTime;

I have already answered the first and third of your difficulties. For the second one, here's a simple approach.

First we need to decide when to light up a radio button. It can be light up after some delay after the user clicks on a start button. To create this delay, use System.Windows.Forms.Timer. You can learn how to use it by going to here. This may also be helpful.

Now create a Random object at class level. This is used to randomly light up the radio buttons

private Random random = new Random();

In the Timer.Tick event handler, first stop the timer because we only want it to fire once. Then you can first generate a random number between 0 and 2:

var randomNumber = random.Next(0, 3);

Then depending on the random number, we light up radio buttons:

if (randomNumber == 0) {
    radioButton1.Checked = true;
} else if (randomNumber == 1) {
    radioButton2.Checked = true;
} else {
    radioButton3.Checked = true;
// this is where you want to start the stopwatch!
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