Improve company productivity with a Business Account.Sign Up

x
  • Status: Solved
  • Priority: Medium
  • Security: Public
  • Views: 660
  • Last Modified:

GDI Drawing Lines triggered off a button click.

I have no problem with the following code:

/***************************
      protected override void OnPaint(PaintEventArgs pe)
      {
            Graphics g = pe.Graphics ;
            Pen L1Pen = new Pen(Color.Red);
            Point L1x = new Point(100, 800);
            Point L1y = new Point(275, 800);
            
            Pen L2Pen = new Pen(Color.Blue);
            Point L2x = new Point(275, 800);
            Point L2y = new Point(625, 800);
            
            Pen L3Pen = new Pen(Color.Orange);
            Point L3x = new Point(625, 800);
            Point L3y = new Point(775, 800);
            
            Pen L4Pen = new Pen(Color.Black);
            Point L4x = new Point(775, 800);
            Point L4y = new Point(950, 800);
            
            
            
            g.DrawLine(L1Pen, L1x, L1y);
            g.DrawLine(L2Pen, L2x, L2y);
            g.DrawLine(L3Pen, L3x, L3y);
            g.DrawLine(L4Pen, L4x, L4y);
      }

***************/

However when I attempt to build the following code to trigger it in a off a button click I receive the following build error: The type or namespace name 'pe' could not be found (are you missing a using directive or an assembly reference?)
.

For example:
/*******************************
private void button1_Click(object sender, System.EventArgs e)
      {
            Graphics g = pe.Graphics ;
            Pen L1Pen = new Pen(Color.Red);
            Point L1x = new Point(100, 800);
            Point L1y = new Point(275, 800);
            
            Pen L2Pen = new Pen(Color.Blue);
            Point L2x = new Point(275, 800);
            Point L2y = new Point(625, 800);
            
            Pen L3Pen = new Pen(Color.Orange);
            Point L3x = new Point(625, 800);
            Point L3y = new Point(775, 800);
            
            Pen L4Pen = new Pen(Color.Black);
            Point L4x = new Point(775, 800);
            Point L4y = new Point(950, 800);
            
            
            
            g.DrawLine(L1Pen, L1x, L1y);
            g.DrawLine(L2Pen, L2x, L2y);
            g.DrawLine(L3Pen, L3x, L3y);
            g.DrawLine(L4Pen, L4x, L4y);
}

**************/
0
int200
Asked:
int200
  • 2
  • 2
1 Solution
 
millsoftCommented:
Hi int200,

In the first function 'pe' is an argument to the Paint function.  You need to get the Graphics object to the window upon which you want to draw in the Click Event.

Is it the Button's parent window?  
For example:

            private void PaintMe( Graphics g )
            {
                  Pen L1Pen = new Pen(Color.Red);
                  Point L1x = new Point(10, 80);
                  Point L1y = new Point(27, 80);
         
                  Pen L2Pen = new Pen(Color.Blue);
                  Point L2x = new Point(27, 80);
                  Point L2y = new Point(62, 80);
         
                  Pen L3Pen = new Pen(Color.Orange);
                  Point L3x = new Point(62, 80);
                  Point L3y = new Point(77, 80);
         
                  Pen L4Pen = new Pen(Color.Black);
                  Point L4x = new Point(77, 80);
                  Point L4y = new Point(95, 80);
         
         
         
                  g.DrawLine(L1Pen, L1x, L1y);
                  g.DrawLine(L2Pen, L2x, L2y);
                  g.DrawLine(L3Pen, L3x, L3y);
                  g.DrawLine(L4Pen, L4x, L4y);
            }

            private void button1_Click(object sender, System.EventArgs e)
            {
                  System.Windows.Forms.Button b = (System.Windows.Forms.Button) sender;
                  PaintMe( b.Parent.CreateGraphics() );
            }
Cheers!
Brad
0
 
int200Author Commented:
Thanks for the response, but I just put in your code and can not see any graphics drawn on the window.  I created a simple C# Windows App, created a button to the form and added your code.
Here is the entire code:

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

namespace GDITest2
{
      /// <summary>
      /// Summary description for Form1.
      /// </summary>
      public class Form1 : System.Windows.Forms.Form
      {
            private System.Windows.Forms.Button button1;
            /// <summary>
            /// Required designer variable.
            /// </summary>
            private System.ComponentModel.Container components = null;

            public Form1()
            {
                  //
                  // Required for Windows Form Designer support
                  //
                  InitializeComponent();

                  //
                  // TODO: Add any constructor code after InitializeComponent call
                  //
            }

            /// <summary>
            /// Clean up any resources being used.
            /// </summary>
            protected override void Dispose( bool disposing )
            {
                  if( disposing )
                  {
                        if (components != null)
                        {
                              components.Dispose();
                        }
                  }
                  base.Dispose( disposing );
            }

            #region Windows Form Designer generated code
            /// <summary>
            /// Required method for Designer support - do not modify
            /// the contents of this method with the code editor.
            /// </summary>
            private void InitializeComponent()
            {
                  this.button1 = new System.Windows.Forms.Button();
                  this.SuspendLayout();
                  //
                  // button1
                  //
                  this.button1.Location = new System.Drawing.Point(72, 64);
                  this.button1.Name = "button1";
                  this.button1.Size = new System.Drawing.Size(96, 32);
                  this.button1.TabIndex = 0;
                  this.button1.Text = "button1";
                  //
                  // Form1
                  //
                  this.AutoScaleBaseSize = new System.Drawing.Size(5, 13);
                  this.ClientSize = new System.Drawing.Size(292, 266);
                  this.Controls.Add(this.button1);
                  this.Name = "Form1";
                  this.Text = "Form1";
                  this.ResumeLayout(false);

            }
            #endregion

            
            private void PaintMe( Graphics g )
            {
                  Pen L1Pen = new Pen(Color.Red);
                  Point L1x = new Point(100, 1000);
                  Point L1y = new Point(100, 825);
         
                  Pen L2Pen = new Pen(Color.Blue);
                  Point L2x = new Point(100, 825);
                  Point L2y = new Point(100, 475);
         
                  Pen L3Pen = new Pen(Color.Orange);
                  Point L3x = new Point(100, 475);
                  Point L3y = new Point(100, 325);
         
                  Pen L4Pen = new Pen(Color.Black);
                  Point L4x = new Point(100, 325);
                  Point L4y = new Point(275, 325);
         
         
         
                  g.DrawLine(L1Pen, L1x, L1y);
                  g.DrawLine(L2Pen, L2x, L2y);
                  g.DrawLine(L3Pen, L3x, L3y);
                  g.DrawLine(L4Pen, L4x, L4y);
            }

            private void button1_Click(object sender, System.EventArgs e)
            {
                  System.Windows.Forms.Button b = (System.Windows.Forms.Button) sender;
                  PaintMe( b.Parent.CreateGraphics() );
            }

            /// <summary>
            /// The main entry point for the application.
            /// </summary>
            [STAThread]
            static void Main()
            {
                  Application.Run(new Form1());
            }
      }
}

Thanks
0
 
millsoftCommented:
There are two possibilites.

First, it doesn't appear the button has a event handler wired up.

You need something like
this.button1.click += new ....

I'm not at my C# machine so I don't have the exact syntax handy.

Second, the Y coordinate you are using (825) is probably off the bottom of the window.  That is why I used 80 instead for testing purposes.

0
 
int200Author Commented:
Hi Brad,

You were correct, I didn't double click on the button from the form which auto-generates the handler.  I just added the button and put the code in.

It works fine now.  Thanks!  By the way, I'm running 1600x1200 so that's why I'm using such large values.

Now, I need to look into how to pass variables a the points so I can use one function I can pass the x and y coorinates to.

Thanks and Best Regards!
0
Question has a verified solution.

Are you are experiencing a similar issue? Get a personalized answer when you ask a related question.

Have a better answer? Share it in a comment.

Join & Write a Comment

Featured Post

Free Tool: SSL Checker

Scans your site and returns information about your SSL implementation and certificate. Helpful for debugging and validating your SSL configuration.

One of a set of tools we are providing to everyone as a way of saying thank you for being a part of the community.

  • 2
  • 2
Tackle projects and never again get stuck behind a technical roadblock.
Join Now