Question

我尝试使用从结构饼中获取的数据来创建饼图。在这个结构中，我有3个计数器（r_count，i_count，j_count）和一个总数（total_count）。我使用了上面的代码但是出现的表单是空的。任何想法或解决方案？

float p1 = pie.r_count / pie.total_instr;
float p2 = pie.i_count / pie.total_instr;
float p3 = pie.j_count / pie.total_instr;

Graphics graphics = pictureBox1.CreateGraphics();

Rectangle rect = new Rectangle(0, 0, 150, 150);

Brush b1 = new SolidBrush(Color.Red);
Brush b2 = new SolidBrush(Color.Blue);
Brush b3 = new SolidBrush(Color.Maroon);

Pen p = new Pen(Color.Black, 2);

graphics.Clear(Form1.DefaultBackColor);
graphics.DrawPie(p, rect, 0, p1);
graphics.FillPie(b1, rect, 0, p1);
graphics.DrawPie(p, rect, p1, p2);
graphics.FillPie(b2, rect, p1, p2);
graphics.DrawPie(p, rect, p2 + p1, p3);
graphics.FillPie(b3, rect, p2 + p1, p3);

Answer 1

您必须将两个integers中的一个投放到float：

float p1 = (float)pie.r_count / pie.total_instr;

或

float p1 = pie.r_count / (float)pie.total_instr;

否则结果将始终为0.为什么？

当我们划分两个整数时，让我们说a和b，那么结果将是0，如果a<b。

根据您的理解，您必须对p2和p3进行相同的更改。

<强>更新

从MSDN，我们看到DrawPie方法的签名如下：

public void DrawPie(
    Pen pen,
    RectangleF rect,
    float startAngle,
    float sweepAngle
)

其中startAngle是从饼形的x轴到第一边顺时针测量的角度，endAngle是从startAngle参数到顺时针的度数测量的角度馅饼形状的第二面。

话虽如此，你必须做出以下改变：

float p1 = ((float)pie.r_count / pie.total_instr)*360;
float p2 = ((float)pie.i_count / pie.total_instr)*360;
float p3 = ((float)pie.j_count / pie.total_instr)*360;

Answer 2

我终于找到了解决这个问题的方法。代码如下所示：

public partial class Form3 : Form
{
    public chart pie;
    Graphics graphics;

    public float d1;
    public float d2;
    public float d3;

    public Form3(chart ch)
    {
        InitializeComponent();
        pie = ch;
        graphics = pictureBox1.CreateGraphics();
    }

    private void Form3_Load(object sender, EventArgs e)
    {

       d1 = 360 * (((float)pie.r_count)/((float)pie.total_instr));
       d2 = 360 * (((float)pie.i_count) / ((float)pie.total_instr));
       d3 = 360 * (((float)pie.j_count) / ((float)pie.total_instr));
       //comboBox1.SelectedIndex = 0;
    }

    private void button1_Click(object sender, EventArgs e)
    {
        SolidBrush b1 = new SolidBrush (Color.Blue);
        SolidBrush b2 = new SolidBrush(Color.Red);
        SolidBrush b3 = new SolidBrush(Color.LawnGreen);
        Rectangle rect = new Rectangle(60,10,200,200);
        Pen p = new Pen(Color.Black);

        graphics.DrawPie(p, rect, 0, d1);
        graphics.FillPie(b1, rect, 0, d1);
        graphics.DrawPie(p, rect, d1, d2);
        graphics.FillPie(b2, rect, d1, d2);
        graphics.DrawPie(p, rect, d1 + d2, d3);
        graphics.FillPie(b3, rect, d1+d2, d3);
        comboBox1.SelectedIndex = 0;

            label1.Text = "R_type   (" + (d1 * 100 / 360).ToString() + "%)";
            label2.Text = "I_type   (" + (d2 * 100 / 360).ToString() + "%)";
            label3.Text = "J_type   (" + (d3 * 100 / 360).ToString() + "%)";
            label5.Enabled = false;




    }

    private void comboBox1_SelectedIndexChanged(object sender, EventArgs e)
    {
        if (comboBox1.SelectedIndex == 0)
        {
            label1.Text = "R_type   (" + (d1 * 100 / 360).ToString() + "%)";
            label2.Text = "I_type   (" + (d2 * 100 / 360).ToString() + "%)";
            label3.Text = "J_type   (" + (d3 * 100 / 360).ToString() + "%)";
            label5.Enabled = false;

        }
        else
        {
            label1.Text = "R_type   (" + (pie.r_count).ToString() + ")";
            label2.Text = "I_type   (" + (pie.i_count).ToString() + ")";
            label3.Text = "J_type   (" + (pie.j_count).ToString() + ")";
            label5.Text += "Total Instructions = " + pie.total_instr.ToString();
            label5.Enabled = true;
        }
    }

结果如下所示！谢谢大家的帮助！

enter image description here

Answer 3

如果pie.total_instr是int你需要这个：

float p1 = pie.r_count / (float)pie.total_instr;

避免在你的情况下始终为0的整数除法

Answer 4

在绘制前将p1，p2，p3乘以360，DrawPie函数取度

float p1 = pie.r_count * 360 / pie.total_instr;
float p2 = pie.i_count * 360 / pie.total_instr;
float p3 = pie.j_count * 360 / pie.total_instr;

使用3个整数的值创建饼图

4 个答案: