Create Ellipse Control in C#

Create your own Ellipse Control in Windows Forms Applications for free without using any third party tool or framework. Ellipse tool is used to round the corners of different elements of C# like a Border Less Form, Panel, GridView e.t.c.

In this short example we’ll create an ellipse tool for C# desktop Applications of WinForm Apps.

Tools Required:

1. Visual Studio 2010 or later version.

Steps to Follow:

1. Open Visual Studio and Create a new windows forms applications project or you continue with your existing WinForm Application Project.
2. Go to the Solution Explorer and right click on project file and Add->Class.
3. Name this class as ElipseControl and inherit it from main Component class.
4. Add the following code:

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Drawing;
using System.Drawing.Drawing2D;
using System.Linq;
using System.Runtime.InteropServices;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;

namespace ElipseToolDemo
{
    class ElipseControl : Component
    {
        private Control hostControl;
        [DllImport("Gdi32.dll", EntryPoint = "CreateRoundRectRgn")]
        private static extern IntPtr CreateRoundRectRgn
            (
               int nLeftRect,
               int nTopRect,
               int nRightRect,
               int nBottomRect,
               int nWidthEllipse,
               int nHeightEllipse
            );
        private Control _cntrl;
        private int _CornerRadius = 30;

        public Control TargetControl
        {
            get { return _cntrl; }
            set
            {
                _cntrl = value;
                _cntrl.SizeChanged += (sender, eventArgs) => _cntrl.Region = Region.FromHrgn(CreateRoundRectRgn(0, 0, _cntrl.Width, _cntrl.Height, _CornerRadius, _CornerRadius));
            }
        }

        public int CornerRadius
        {
            get { return _CornerRadius; }
            set
            {
                _CornerRadius = value;
                if(_cntrl != null)
                    _cntrl.Region = Region.FromHrgn(CreateRoundRectRgn(0, 0, _cntrl.Width, _cntrl.Height, _CornerRadius, _CornerRadius));
            }
        }
       
       
    }
}

In this control, we have added two main properties which are TargetControl and CornerRadius. From the target Control property, we can select the control on which we want to add the ellipse (round corner) effect. From border Radius Property, we can set the roundness of the borders of the Targeted Control.

Video Tutorial:

Watch full video tutorial to learn how to create ellipse control in C#.

Source Code:

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