CODEWITHSUNDEEP
c#forms
Lyrk
Lyrk

Reputation: 2000

How to randomize Color enum in windows forms?

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;

namespace painter
{
public partial class Form1 : Form
{        
    Array values = Enum.GetValues(typeof(Color));
    Random random = new Random();

    public bool shouldpaint = false;
    public Form1()
    {
        InitializeComponent();
    }

    private void Form1_MouseDown(object sender, MouseEventArgs e)
    {
        shouldpaint = true;
    }

    private void Form1_MouseUp(object sender, MouseEventArgs e)
    {
        shouldpaint = false;
    }

    private void Form1_MouseMove(object sender, MouseEventArgs e)
    {
        if (shouldpaint == true)
        {
            Graphics a = CreateGraphics();

            Color randomColor = (Color)values.GetValue(random.Next(values.Length));

            a.FillEllipse(new SolidBrush(randomColor), e.X, e.Y, 5, 5);
        }
    }
}

}

I am trying to randomize SolidBrush(randomColor) so that when I move my mouse, its color will change and painted accordingly. I tried above code, it gave me "An unhandled exception of type 'System.ArgumentException' occurred in mscorlib.dll" . Can you check my randomization code? Before I added that code it was working as intended according to my predetermined color.

Upvotes: 0

Views: 142

Answers (1)

Morcilla de Arroz
Morcilla de Arroz

Reputation: 2172

If you want random colors, you have to create random number, into the max a min values allowed by the Color Enum.

I think it's better to forget the color enum, to use the old RGB constructor instead.

Dim oRandomNumbers As New Random
Dim oColor as Color 
oColor =Color.FromArgb(255, _
        oRandomNumbers.Next(0, 256), _
        oRandomNumbers.Next(0, 256), _
        oRandomNumbers.Next(0, 256))

In c#:

Random oRandomNumbers = new Random();
Color oColor = default(Color);
oColor = Color.FromArgb(255, oRandomNumbers.Next(0, 256),
                        oRandomNumbers.Next(0, 256), 
                        oRandomNumbers.Next(0, 256));

Edit: As @Enigmativity says, 256 its the exclusive upper limit, so this will give you random numbers from 0 to 255

Upvotes: 3

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