Send a bmp to main Form from a class

Question

3.00/5 (2 votes)

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I want send a bmp from a class to picturebox in main form.
I think that may use delegate, but i don´t know how make it.

using System;
using System.Drawing;
using System.Windows.Forms;

namespace WindowsFormsApplication1
{
    public partial class Form1 : Form
    {
        class clsLoadBmp
        {
            public void LoadBmp()
            {
                Bitmap bmp = (Bitmap)Image.FromFile("c:\\test.jpg");
                UpdatePictureBox(bmp);
            }
        }

        public Form1()
        {
            InitializeComponent();
        }

        private void button1_Click(object sender, EventArgs e)
        {
            clsLoadBmp n = new clsLoadBmp();
            n.LoadBmp();
        }

        public void UpdatePictureBox(Bitmap bmp)
        {
            this.pictureBox1.Image = bmp;
        }
    }
}

Can you help me?

Thanks in advance.

Posted 1-Jul-14 10:22am

lostysoft

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Comments

Sergey Alexandrovich Kryukov 1-Jul-14 16:51pm

The request makes little sense. What do you really want? "From class to a picturebox"? And what, PictureBox is not a class, or what? You work not with classes, but instances (objecT) To show a bitmap on request? But what's the problem then? Where is the code which is supposed to "send" anything? What don't you know?

In all cases, you are not "sending" anything; this is the same process, same application. Also, there are no cases when hard-coded file paths could be useful (like "c:\test.jpg"). In newer version of Windows, 7 or 8, this path is not even legitimate.

—SA

3 solutions

Solution 1

Hello,

First I would recommend you read about delegates, a good start is MSDN:
http://msdn.microsoft.com/en-us/library/orm-9780596521066-01-17.aspx[^]

Anyway here is a way to do it using delegates:

public partial class Form1 : Form
{	
	public Form1()
	{
		InitializeComponent();
	}
	
	static void Loader(PictureBox pict)
    	{
        	Bitmap bmp = (Bitmap)Image.FromFile("c:\\test.jpg");
	        pict.Image = bmp;
    	}		
	
	void button1_Click(object sender, EventArgs e)
	{
		LoadBmpHelper myLoader = new LoadBmpHelper();
		LoadBmpHelper.PictureHandler loader = new LoadBmpHelper.PictureHandler(Loader);
        	myLoader.LoadBmp(loader, pictureBox1);
	}
}

public class LoadBmpHelper
{
    public delegate void PictureHandler(PictureBox pict);

    public void LoadBmp(PictureHandler pictureHandler, PictureBox pict)
    {
        if (pictureHandler != null)
        {
            pictureHandler(pict);
        }
    }
}

A delegate is a reference to a method, basically you declare a method signature. When you use the class that contains the delegate you pass it your own method that matches the signature. It's basically an easy way to decouple class.

Valery.

Posted 1-Jul-14 12:58pm

Valery Possoz

Solution 2

Hello

C#

using System;
using System.Drawing;
using System.Windows.Forms;

namespace WindowsFormsApplication1
{
    public partial class Form1 : Form
    {
        class clsLoadBmp
        {
            public Bitmap LoadBmp()
            {
                Bitmap bmp = (Bitmap)Image.FromFile("c:\\test.jpg");
                return bmp;
            }
        }

        public Form1()
        {
            InitializeComponent();
        }

        private void button1_Click(object sender, EventArgs e)
        {
            clsLoadBmp n = new clsLoadBmp();
            UpdatePictureBox(n.LoadBmp());
        }

        public void UpdatePictureBox(Bitmap bmp)
        {
            this.pictureBox1.Image = bmp;
        }
    }
}

Posted 1-Jul-14 19:28pm

CB Sharma

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lostysoft · Accepted Answer · 2014-07-10T08:39:00

Thanks to Valery. Your solution is not good for me, but your link was very usefull. This put me in the correct way. This is the code working:

using System;
using System.Drawing;
using System.Windows.Forms;

namespace WindowsFormsApplication1
{
    public partial class Form1 : Form
    {
        class clsLoadBmp
        {
            public delegate void BmpChangeHandler(Bitmap bmp);
            public BmpChangeHandler BmpChanged;

            public void LoadBmp()
            {

                Bitmap bmp = (Bitmap)Image.FromFile("c:\\test.jpg");
                BmpChanged(bmp);
            }
        }

        public Form1()
        {
            InitializeComponent();
        }

        private void button1_Click(object sender, EventArgs e)
        {
            clsLoadBmp n = new clsLoadBmp();
            n.BmpChanged += new clsLoadBmp.BmpChangeHandler(UpdatePictureBox);
            n.LoadBmp();
        }

        public void UpdatePictureBox(Bitmap bmp)
        {
            this.pictureBox1.Image = bmp;
        }
    }
}