关于c＃：不返回传递的值

Passed value is not returned

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// here is the full code.
// I would expect the btnLine_Click() method to start the timer (which it does) and then
// accept"angle" from the"public float myangle" getter but it does not. So it only draws // one 30 degree hard coded line. I desire the line to be incremented around in 10
// degree steps sort of like the second hands of a clock.

using System;
using System.Drawing;
using System.Drawing.Drawing2D;
using System.Collections;
using System.ComponentModel;
using System.Windows.Forms;
using System.Data;
using System.Drawing.Imaging;
using System.Collections.Generic;
using System.Text.RegularExpressions;
using System.IO;
using System.Text;

namespace DrawingShapesApp
{
public class Form1 : Form
{
private Bitmap DrawingArea;
private Pen myPen;
private System.Windows.Forms.Timer timer1;
private System.ComponentModel.IContainer components;
private Button btnLine;
float angle;
public float x1=300; // 1st point pair
public float y1=500;
public float x2=500; // 2nd point pair
public float y2=300;
public double angleX = 30; // 30 degrees
public double Xdist;

public double sqrt;

public Form1()
{
InitializeComponent();
}

protected override void Dispose( bool disposing )
{
if( disposing )
{
if (components != null)
{
components.Dispose();
}
}
base.Dispose( disposing );
}

private void InitializeComponent()
{
this.ClientSize = new System.Drawing.Size(800, 650);
this.Text="line5";
this.components = new System.ComponentModel.Container();
this.timer1 = new System.Windows.Forms.Timer(this.components);
this.SuspendLayout();

btnLine = new Button();
this.btnLine.Location = new System.Drawing.Point(8, 88);
this.btnLine.Name ="btnLine";
this.btnLine.Size = new System.Drawing.Size(40, 40);
this.btnLine.TabIndex = 1;
this.btnLine.Text ="Step";
this.Controls.Add(this.btnLine);

// Load this"frmGraphics_Load" at load time
this.Load += new System.EventHandler(this.frmGraphics_Load);
this.Closed += new System.EventHandler(this.frmGraphics_Closed);
this.Paint += new System.Windows.Forms.PaintEventHandler(this.frmGraphics_Paint);
this.ResumeLayout(false);
myPen = new Pen(Color.Blue);
this.btnLine.Click += new System.EventHandler(this.btnLine_Click);
}

static void Main()
{
Application.Run(new Form1());
}

private void frmGraphics_Load(object sender, System.EventArgs e) // a clickable event
{
Console.WriteLine("First...load this: frmGraphics_Load");
// create a new bitmap...defining the bitmap the same size as the form
DrawingArea = new Bitmap(
this.ClientRectangle.Width,
this.ClientRectangle.Height,
System.Drawing.Imaging.PixelFormat.Format24bppRgb);
InitializeDrawingArea();
}

// copy from bitmap to the form
private void InitializeDrawingArea()
{
Graphics oGraphics; // oGraphics is the form
oGraphics = Graphics.FromImage(DrawingArea); // copy bitmap to form
myPen.Color = Color.AliceBlue;
for ( int x = 0; x 359)
angle=0;
Console.WriteLine("**timer1 angle= {0}", angle);
float myangle = angle;
if(angle == 90)
this.timer1.Enabled = false;
Invalidate();
}

public float myangle
{
set { angle = value; }
get { return angle; }
}

private void btnLine_Click(object sender, System.EventArgs e)
{
this.timer1.Enabled = true;
this.timer1.Tick += new System.EventHandler(this.timer1_Tick);
// timer now active...why does it not take the angle from timer1_Tick() ?
// I need to increment the drawline by 10 degrees like the hand of a clock

Console.WriteLine("in btnLine_Click");

// draws a hardcoded line but cannot get"angle" from timer1_Tick()
Graphics oGraphics;
oGraphics = Graphics.FromImage(DrawingArea); // copy from bitmap to form
Pen Grn = new Pen(Color.Green, 2);
Pen penBlue = new Pen(Color.Blue, 1);
Rectangle rect = new Rectangle(100, 100, 400, 400); // draw circle
oGraphics.DrawEllipse( penBlue, rect );
oGraphics.DrawLine(Grn, 300, 300, 500, 300); // draw horiz. line

PointF p1 = new PointF(x1, y1);
PointF p2 = new PointF(x2, y2);
double Xdist = Math.Abs(p2.X - p1.X);
Console.WriteLine("Xdist= {0}", Xdist);

double angle30 = Math.Cos(DegreeToRadian(30)); // need myangle in place of 30
Console.WriteLine("angle30= {0}", angle30);

double side_c = Math.Tan(DegreeToRadian(angleX)) * Xdist;
Console.WriteLine("side_c= {0}", side_c);

sqrt = (Xdist*Xdist + side_c*side_c);
double side_a = Math.Sqrt(sqrt);
Console.WriteLine("side_a= {0}", side_a);

// this draws a
oGraphics.DrawLine(Grn, 300, 300, 300+(float)173.21, 300-100); // intersects circle
oGraphics.DrawLine(Grn, 300+(float)173.21, 300, 300+(float)173.21, 300-100); // draw vert. line

oGraphics.Dispose(); // clean up graphics object
this.Invalidate(); // force form to redraw itself
}

private double DegreeToRadian(double angle)
{
return Math.PI * angle / 180.0;
}

private double RadianToDegree(double angle)
{
return angle * (180.0 / Math.PI);
}

public void timer_stop()
{
Console.WriteLine("Halting timer!");
this.timer1.Enabled = false; // halts operation
}

}

}