How to remove the black border from the disabled button?-CodePudding

I created a changing_button with a background image. The FlatAppearance.BorderSize property of this button is zero, so normally it displays without a border. But if I make changing_button disabled, it will have a black border:

border around my button

How can I remove this border?

I guess that the border appears because changing_button is in focus then I change its Enable property. For that reason, I tried to remove focus from the button and set changing_button.TabStop = false, but it didn't help.

using System;
using System.Drawing;
using System.Windows.Forms;

namespace winforms_test_1
{
    public partial class Form1 : Form
    {
        Button changing_button;

        private readonly Image enable_img = Image.FromFile("D://images//enable_img.png");
        private readonly Image disable_img = Image.FromFile("D://images//disable_img.png");

        public Form1()
        {
            InitializeComponent();
            TableLayoutPanel main_panel = new TableLayoutPanel
            {
                BackColor = Color.White,
                Dock = DockStyle.Fill
            };

            CreateButton();

            Controls.Add(changing_button);
        }

        private void CreateButton()
        {
            changing_button = new Button
            {
                BackgroundImage = enable_img,
                BackgroundImageLayout = ImageLayout.Center,
                TabIndex = 1,
                TabStop = false,
                FlatStyle = FlatStyle.Flat,
                Margin = new Padding(10, 10, 0, 0),
                Location = new Point(40, 40),
            };
            changing_button.FlatAppearance.BorderSize = 0;
            changing_button.Size = new Size(80, 50);

            changing_button.Click  = new System.EventHandler(this.Button_Click);
        }

        void Button_Click(object sender, EventArgs e)
        {
            changing_button.BackgroundImage = disable_img;
            changing_button.Enabled = false;
            changing_button.TabStop = false;


        }
    }
}

enable_img.png: enter image description here disable_img.png:

CodePudding user response：

To workaround this, I set the border size to 1.

Then set the border color to be the same color of BackColor. Just change on the click event to match the current state.