Help with this PieChart control

Alan Zhao

hi, I've been coding this PieChart control all day now, just couldn't get it to work, if you know how to write a custom control, plese help me. The main problem I have here is at the OnPaint() the PieChart doesn't draw all the pies except the first pie. What am I missing on writing a custom control here? Complete codes are below or you can download the project here PieChart.cs

using System;
using System.Collections;
using System.ComponentModel;
using System.ComponentModel.Design;
using System.Drawing;
using System.Drawing.Drawing2D;
using System.Drawing.Design;
using System.Data;
using System.Windows.Forms;

namespace ColorControl.Controls
{
public class PieChart : System.Windows.Forms.Control
{
// collection
private PieChartItemCollection _Items = new PieChartItemCollection();

    public PieChart() 
    { 
        base.Size = new Size(200, 200); 
        SetStyle( 
            ControlStyles.AllPaintingInWmPaint | 
            ControlStyles.ResizeRedraw | 
            ControlStyles.DoubleBuffer | 
            ControlStyles.UserPaint, 
            true 
            ); 
    } 
     
    public PieChartItemCollection Items 
    { 
        get 
        { 
            return \_Items; 
        } 
        set 
        { 
            \_Items = value; 
            this.Invalidate(); 
        } 
    } 

    protected override void OnPaint(System.Windows.Forms.PaintEventArgs e) 
    { 
        int valueSum = 0; 
        int startDegree = 0; 
        int sweepDegree; 

        // sum of values 
        foreach (PieChartItem item in \_Items) 
        { 
            valueSum += (int)item.Value; 
        } 

        e.Graphics.SmoothingMode = SmoothingMode.AntiAlias; 
        Rectangle rect = new Rectangle(ClientRectangle.X, ClientRectangle.Y, 
            ClientRectangle.Width - 1, ClientRectangle.Height - 1); 

        if (valueSum != 0) 
        { 
            // draw each pie 
            foreach (PieChartItem item in \_Items) 
            { 
                // degree of each pie 
                sweepDegree = (int)(item.Value / valueSum \* 360); 

                SolidBrush brush = new SolidBrush(item.Color);

leppie

You should use Matrix transforms to rotate the drawing "canvas".

top secret AdvancedTextBox

Alan Zhao

Can you explain please, I really want this control to work. Thank!