C# Simple app to convert images into Base64 asynchronously-CodePudding

I'm trying to make a simple winforms app to convert an image to Base64. When debugging I notice that the ui freezes when I click the button to convert to base64, so I started making changes in the code to call the method asynchronously. (It happens that I never used Async methods so I kinda don't know what I'm doing)

My form1.cs code:

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 ImageToBase64
{
    public partial class main : Form
    {
        public main()
        {
            InitializeComponent();
        }

        Util Util = new Util();

        private void button1_Click(object sender, EventArgs e)
        {
            imageDialog.FileName = "";
            imageDialog.Title = "Selecionar Imagem";
            imageDialog.Filter = "JPEG|*.JPG|PNG|*.png";
            imageDialog.ShowDialog();
            imagePathText.Text = imageDialog.FileName;
        }

        private void button2_Click(object sender, EventArgs e)
        {
            imageCode.Text = "";
            Task<string> base64Code = Task.Run(() => Util.ToBase64(imageDialog.FileName));
            imageCode.Text = base64Code.Result;
            
        }
    }
}

My Util.cs code:

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

namespace ImageToBase64
{
    class Util
    {
        public async Task<string> ToBase64(string img)
        {
            string path = img;
            using (System.Drawing.Image image = System.Drawing.Image.FromFile(path))
            {
                using (MemoryStream m = new MemoryStream())
                {
                    image.Save(m, image.RawFormat);
                    byte[] imageBytes = m.ToArray();
                    string base64String = null;
                    base64String = Convert.ToBase64String(imageBytes);
                    return base64String;
                }
            }
        }
    }
}

Even after these changes the UI still freezes, what can I do to fix that?

CodePudding user response：

First, the code blocks the task. Second, the method ToBase64 ends up producing and encoding the original bytes, assuming nothing is lost due to lossy compression. image.Save(m, image.RawFormat); saves the image data in the original format, so at best it produces the same data.

The code could be reduced to:

private async void button2_Click(object sender, EventArgs e)
{
    //Only needed to provide a visual cue
    imageCode.Text="";
    var bytes=await File.ReadAllBytes(imageDialog.FileName);
    imageCode.Text = await Task.Run(()=>Convert.ToBase64String(bytes));
}

Using an Image would make sense if you wanted to convert the image to a different format before encoding, or if you wanted to encode the raw RGB values

CodePudding user response：

The reason is this

imageCode.Text = base64Code.Result;

.Result will block until the string can be produced, and that is probably not what you want.

You should instead be using async/await:

imageCode.Text = await base64Code;

Note that this requires the method to be marked as async. And you probably also want to catch any exceptions, since they otherwise risk being lost.

I would also recommend using some profiling tools, since these can usually tell you what parts of the code is blocking the UI.