这个程序应该像加入点一样工作，用户选择要显示的点数并且能够在画布上绘制，问题在于保存，每当我尝试保存它根本不工作时，它给出我是一个黑色的矩形..
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Drawing.Imaging;
using System.Linq;
using System.Text;
using System.Windows.Forms;
using System.Threading;
namespace Painting2
{
public partial class Form1 : Form
{
Bitmap drawing;
bool draw = false;
Color C = Color.Black;
int size = 14;
bool startdraw = false;
public Form1(string parameter1)
{
InitializeComponent();
this.Text = parameter1;
}
private void Form1_Load(object sender, EventArgs e)
{
drawing = new Bitmap (pnlcanvas.Width, pnlcanvas.Height, pnlcanvas.CreateGraphics());
cbdots.Items.Add("2");
cbdots.Items.Add("3");
cbdots.Items.Add("4");
cbdots.Items.Add("5");
cbdots.Items.Add("6");
cbdots.Items.Add("7");
cbdots.Items.Add("8");
cbdots.Items.Add("9");
cbdots.Items.Add("10");
cbdots.Items.Add("11");
cbdots.Items.Add("12");
cbdots.Items.Add("13");
cbdots.Items.Add("14");
cbdots.Items.Add("15");
}
private void pnlcanvas_MouseDown(object sender, MouseEventArgs e)
{
draw = true;
Graphics g = Graphics.FromImage(drawing);
SolidBrush b = new SolidBrush(C);
if (startdraw == true)
{
g.FillEllipse(b, e.X, e.Y, size, size);
pnlcanvas.CreateGraphics().DrawImageUnscaled(drawing, new Point(0, 0));
}
}
private void pnlcanvas_MouseUp(object sender, MouseEventArgs e)
{
draw = false;
}
private void pnlcanvas_Move(object sender, EventArgs e)
{
}
private void pnlcanvas_MouseMove(object sender, MouseEventArgs e)
{
if (draw == true && startdraw == true)
{
Graphics g = Graphics.FromImage(drawing);
SolidBrush b = new SolidBrush(C);
g.FillEllipse(b, e.X, e.Y, size, size);
pnlcanvas.CreateGraphics().DrawImageUnscaled(drawing, new Point(0, 0));
}
}
private void btncolor_Click(object sender, EventArgs e)
{
}
private void button1_Click(object sender, EventArgs e)
{
C = Color.White;
size = 25;
}
private void button2_Click(object sender, EventArgs e)
{
drawing = new Bitmap(pnlcanvas.Width, pnlcanvas.Height, pnlcanvas.CreateGraphics());
pnlcanvas.CreateGraphics().Clear(Color.White);
}
private void comboBox1_SelectedIndexChanged(object sender, EventArgs e)
{
}
private void btnsave_Click(object sender, EventArgs e)
{
//if (saveDialog.ShowDialog() == DialogResult.OK)
//{
// Bitmap tosave = new Bitmap(pnlcanvas.Width, pnlcanvas.Height);
// pnlcanvas.DrawToBitmap(tosave, new Rectangle(0, 0, pnlcanvas.Width, pnlcanvas.Height));
// tosave.Save(saveDialog.FileName, System.Drawing.Imaging.ImageFormat.Jpeg);
//}
using (Bitmap bitmap = new Bitmap(pnlcanvas.ClientSize.Width,
pnlcanvas.ClientSize.Height))
{
pnlcanvas.DrawToBitmap(bitmap, pnlcanvas.ClientRectangle);
bitmap.Save(@"C:\Users\xejns_000\Desktop\TestDrawToBitmap.bmp", ImageFormat.Bmp);
}
}
private void label2_Click(object sender, EventArgs e)
{
}
private void label3_Click(object sender, EventArgs e)
{
}
private void btnstart_Click(object sender, EventArgs e)
{
DialogResult result = cd.ShowDialog();
if (result == DialogResult.OK)
{
C = cd.Color;
}
startdraw = true;
}
private void cbdots_SelectedIndexChanged(object sender, EventArgs e)
{
drawing = new Bitmap(pnlcanvas.Width, pnlcanvas.Height, pnlcanvas.CreateGraphics()); //clearing
pnlcanvas.CreateGraphics().Clear(Color.White); //clearing
Random r = new Random();
for (int i = 0; i <= Convert.ToInt32(cbdots.SelectedItem.ToString()) -1; i++)
{
Color RandC = Color.Black; ;
int randomcolor = r.Next(1, 11);
int randomx = r.Next(10, 730);
int randomy = r.Next(10, 390);
switch (randomcolor) // choosing random color
{
case 1:
RandC = Color.PaleVioletRed;
break;
case 2:
RandC = Color.PowderBlue;
break;
case 3:
RandC = Color.Fuchsia;
break;
case 4:
RandC = Color.DarkGoldenrod;
break;
case 5:
RandC = Color.LavenderBlush;
break;
case 6:
RandC = Color.Tomato;
break;
case 7:
RandC = Color.SpringGreen;
break;
case 8:
RandC = Color.Wheat;
break;
case 9:
RandC = Color.Salmon;
break;
case 10:
RandC = Color.LightSteelBlue;
break;
}
Graphics g = Graphics.FromImage(drawing); // painting dots
SolidBrush b = new SolidBrush(RandC); // painting dots
g.FillEllipse(b, randomx, randomy, 40, 40); // painting dots
pnlcanvas.CreateGraphics().DrawImageUnscaled(drawing, new Point(0, 0));
}
}
}
}