KeyDown and MouseWheel don t working in c#

Question

KeyDown and MouseWheel don t working in c#, the function does not fire and nothing happens.

I first tried:

add the ImageForm_KeyDown property of the keydown event through the graphical interface, without success.

Then I tried adding this.KeyDown += ImageForm_KeyDown. unsuccessfully.

Then I tried adding this.KeyDown += new KeyEventHandler(ImageForm_KeyDown), without success.

Then I tried following this tutorial https://learn.microsoft.com/pt-br/dotnet/api/system.windows.forms.control.isinputkey?view=windowsdesktop-7.0, also without success.

I only got the mousewheel.

Follow source code:

using System;

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

namespace app_manga12
{
    public partial class Form1 : Form
    {


        int Index;
        List<string> Caminho;
        string caminho2;
        
        public Form1(string Caminho2, List<string> caminho, int index)
        {


            InitializeComponent();
            Index = index;
            Caminho = caminho;
            caminho2 = Caminho2;
            KeyPreview = true;
        }

        private void Form1_Load(object sender, EventArgs e)
        {
            //flowLayoutPanel1.BackgroundImage = Image.FromFile(@Caminho[Index]);
            BackgroundImage = Image.FromFile(@caminho2);
            BackgroundImageLayout = ImageLayout.Center;
          //  SizeMode = PictureBoxSizeMode.Zoom;

        }

        private void button1_Click(object sender, EventArgs e)
        {
            // flowLayoutPanel1.BackgroundImage = Image.FromFile(@Caminho[++Index]);
            BackgroundImage = Image.FromFile(@Caminho[++Index]);
            BackgroundImageLayout = ImageLayout.Center;
            //    SizeMode = PictureBoxSizeMode.Zoom;
        }

        private void ImageForm_KeyDown(object sender, KeyEventArgs e)
        {
            if (e.KeyCode == Keys.Right || e.KeyCode == Keys.Space)
            {
                BackgroundImage = Image.FromFile(@Caminho[++Index]);
                BackgroundImageLayout = ImageLayout.Center;
            }
            else if (e.KeyCode == Keys.Left)
            {
                BackgroundImage = Image.FromFile(@Caminho[--Index]);
                BackgroundImageLayout = ImageLayout.Center;
            }
        }

        private void ImageForm_MouseWheel(object sender, MouseEventArgs e)
        {
            if (e.Delta > 0)
            {
                BackgroundImage = Image.FromFile(@Caminho[++Index]);
                BackgroundImageLayout = ImageLayout.Center;
            }
            else if (e.Delta < 0)
            {
                BackgroundImage = Image.FromFile(@Caminho[--Index]);
                BackgroundImageLayout = ImageLayout.Center;
            }
        }

        private void button2_Click(object sender, EventArgs e)
        {
           // flowLayoutPanel1.BackgroundImage = Image.FromFile(@Caminho[--Index]);
            BackgroundImage = Image.FromFile(@Caminho[--Index]);
            BackgroundImageLayout = ImageLayout.Center;
            //  SizeMode = PictureBoxSizeMode.Zoom;
        }
    }
}

Answer 1

don t working in c#,

"Don't working" means what in detail? Error message, unexpected behaviour or ...?

Answer 2

Hi,

There is no information about relationship between Form1 and ImageForm. You put the Key Down function of ImageForm in From1.

Does ImageForm_KeyDown belong to Form1?

Please ensure the KeyDown event is bound in form's properties and add break points to check.

You can also use this.KeyDown += ImageForm_KeyDown in the initialization of form.

Best regards,

Minxin Yu

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