How to Create a Circular ProgressBar

Environment

Product Version	Product	Author
2019.3.917	RadProgressBar for WinForms	Desislava Yordanova

Description

The main purpose of RadProgressBar is to indicate progress. However, it doesn't offer circular style. This tutorial aims to demonstrate a sample approach how to achieve a circular progress bar using the existing circular waiting styles for RadWaitingBar

Solution

Create a derivative of RadWaitingBar and manipulate the InitialStartElementAngle, SweepAngle and MinSweepAngle to represent the equivalent value within the range [0-100]. A sample implementation is demonstrated in the following code snippet:

• C#
• VB.NET

        public class CircularProgressBar : RadWaitingBar
        {
            private decimal _value;
            private Color _color;

            public override string ThemeClassName
            {
                get
                {
                    return typeof(RadWaitingBar).FullName;
                }
            }

            protected override RadWaitingBarElement CreateWaitingBarElement()
            {
                RadWaitingBarElement waitingElement = base.CreateWaitingBarElement();
                waitingElement.WaitingStyle = Telerik.WinControls.Enumerations.WaitingBarStyles.FadingRing;
                FadingRingWaitingBarIndicatorElement indicator = waitingElement.ContentElement.WaitingIndicators[0] as FadingRingWaitingBarIndicatorElement;
                this._color = Color.Blue;
                waitingElement.Text = "0 %";

                indicator.InitialStartElementAngle = 90;
                indicator.SweepAngle = 360;
                indicator.MinSweepAngle = 0;

                return waitingElement;
            }

            public decimal ProgressValue
            {
                get
                {
                    return this._value;
                }

                set
                {
                    _value = value;
                    FadingRingWaitingBarIndicatorElement indicator = 
                        this.WaitingBarElement.ContentElement.WaitingIndicators[0] as FadingRingWaitingBarIndicatorElement;
                    this.WaitingBarElement.Text = value + "%";
                    indicator.MinSweepAngle = (int)ConvertProgressValueToAngle(value);
                    UpdateVisualStyles();
                }
            }

            public Color ProgressColor
            {
                get
                {
                    return _color;
                }
                set
                {
                    this._color = value;
                    FadingRingWaitingBarIndicatorElement indicator = 
                        this.WaitingBarElement.ContentElement.WaitingIndicators[0] as FadingRingWaitingBarIndicatorElement;
                    indicator.ElementColor = this.ProgressColor;
                    indicator.ElementColor2 = this.ProgressColor;
                }
            }

            private void UpdateVisualStyles()
            {
                FadingRingWaitingBarIndicatorElement indicator = 
                    this.WaitingBarElement.ContentElement.WaitingIndicators[0] as FadingRingWaitingBarIndicatorElement;
                indicator.ElementColor = this.ProgressColor;
                indicator.ElementColor2 = this.ProgressColor;
                indicator.GradientStyle = Telerik.WinControls.GradientStyles.Solid;
                indicator.InnerRadius = this.Width / 4 + 10;
                indicator.Radius = this.Width / 4 + 20;
            }

            private decimal ConvertProgressValueToAngle(decimal value)
            {
                decimal angleValue = 0;
                angleValue = value * 360 / 100;
                return angleValue;
            }
        } 

        CircularProgressBar circularProgressBar = new CircularProgressBar();

        public RadForm1()
        {
            InitializeComponent();

            circularProgressBar.Size = new Size(100, 100);
            circularProgressBar.Location = new Point(10, 10);
            this.Controls.Add(circularProgressBar);
            circularProgressBar.ProgressValue = 50;
            circularProgressBar.ProgressColor = Color.DarkRed;
            circularProgressBar.BackColor = Color.Transparent;
            circularProgressBar.WaitingBarElement.DrawBorder = false;

        }

    Public Class CircularProgressBar
        Inherits RadWaitingBar

        Private _value As Decimal
        Private _color As Color

        Public Overrides Property ThemeClassName As String
            Get
                Return GetType(RadWaitingBar).FullName
            End Get
            Set(value As String)
                MyBase.ThemeClassName = value
            End Set
        End Property

        Protected Overrides Function CreateWaitingBarElement() As RadWaitingBarElement
            Dim waitingElement As RadWaitingBarElement = MyBase.CreateWaitingBarElement()
            waitingElement.WaitingStyle = Telerik.WinControls.Enumerations.WaitingBarStyles.FadingRing
            Dim indicator As FadingRingWaitingBarIndicatorElement = TryCast(waitingElement.ContentElement.WaitingIndicators(0), FadingRingWaitingBarIndicatorElement)
            Me._color = Color.Blue
            waitingElement.Text = "0 %"
            indicator.InitialStartElementAngle = 90
            indicator.SweepAngle = 360
            indicator.MinSweepAngle = 0
            Return waitingElement
        End Function

        Public Property ProgressValue As Decimal
            Get
                Return Me._value
            End Get
            Set(ByVal value As Decimal)
                _value = value
                Dim indicator As FadingRingWaitingBarIndicatorElement = _
                    TryCast(Me.WaitingBarElement.ContentElement.WaitingIndicators(0), FadingRingWaitingBarIndicatorElement)
                Me.WaitingBarElement.Text = value & "%"
                indicator.MinSweepAngle = CInt(ConvertProgressValueToAngle(value))
                UpdateVisualStyles()
            End Set
        End Property

        Public Property ProgressColor As Color
            Get
                Return _color
            End Get
            Set(ByVal value As Color)
                Me._color = value
                Dim indicator As FadingRingWaitingBarIndicatorElement = _
                    TryCast(Me.WaitingBarElement.ContentElement.WaitingIndicators(0), FadingRingWaitingBarIndicatorElement)
                indicator.ElementColor = Me.ProgressColor
                indicator.ElementColor2 = Me.ProgressColor
            End Set
        End Property

        Private Sub UpdateVisualStyles()
            Dim indicator As FadingRingWaitingBarIndicatorElement = _
                TryCast(Me.WaitingBarElement.ContentElement.WaitingIndicators(0), FadingRingWaitingBarIndicatorElement)
            indicator.ElementColor = Me.ProgressColor
            indicator.ElementColor2 = Me.ProgressColor
            indicator.GradientStyle = Telerik.WinControls.GradientStyles.Solid
            indicator.InnerRadius = Me.Width / 4 + 10
            indicator.Radius = Me.Width / 4 + 20
        End Sub

        Private Function ConvertProgressValueToAngle(ByVal value As Decimal) As Decimal
            Dim angleValue As Decimal = 0
            angleValue = value * 360 / 100
            Return angleValue
        End Function
    End Class

    Private _circularProgressBar As CircularProgressBar = New CircularProgressBar()

    Public Sub New()
        InitializeComponent()

        _circularProgressBar.Size = New Size(100, 100)
        _circularProgressBar.Location = New Point(10, 10) 
        Me.Controls.Add(_circularProgressBar)
        _circularProgressBar.ProgressValue = 50
        _circularProgressBar.ProgressColor = Color.DarkRed
        _circularProgressBar.BackColor = Color.Transparent
        _circularProgressBar.WaitingBarElement.DrawBorder = False

    End Sub