How to apply Filter to url load image c#

Question

I am using this method to load the image to my picturebox:

private void asdToolStripMenuItem_Click(object sender, EventArgs e)
    {
        pictureBox1.Load(textBox1.Text);
        pictureBox1.Visible = true;
    }

The image is loaded perfectly, but when I apply any filter to the image I get error:

Object reference not set to an instance of an object.

So how can I connect my url loaded image to my filters of image processing like gray, RGB and more...

in my menu strip i create an gray filter for example it is working well for openfiledialog image load but i get error when i load it with url This is my gray filter code: https://jpst.it/YovG — mohamed momo, Apr 26 '17 at 15:56
This is my whole code Ofir Winegarten : https://jpst.it/Yowb — mohamed momo, Apr 26 '17 at 16:00
This the whole code from the beginning to the end : https://jpst.it/YoD4 — mohamed momo, Apr 26 '17 at 16:35
the line who causes the error: Bitmap gimage = new Bitmap(img); — mohamed momo, Apr 26 '17 at 16:37

score 0 · Answer 1 · edited May 23 '17 at 11:54

0

You're getting a NullReferenceExceptionat the line

Bitmap gimage = new Bitmap(img);

because img has not been assigned a value. You need to give it a value when you load a new image, something like:

private void asdToolStripMenuItem_Click(object sender, EventArgs e)
{
    pictureBox1.Load(textBox1.Text);
    pictureBox1.Visible = true;
    img = new Bitmap(textBox1.Text); //Add this line.
}

I noticed you already had this line inside saveToolStripMenuItem_Click, but not inside asdToolStripMenuItem_Click

Edit: If you're loading a bitmap from a URL, you can't load directly into a bitmap object like you would for a pictureBox. Check out Download image and create bitmap to learn how to do it.

edited May 23 '17 at 11:54

Community

1
1

answered Apr 26 '17 at 16:52

Tee

414
2
8
19

i added this line : 'img = new Bitmap(textBox1.Text);' now i get this error: **The given path's format is not supported.** and the image not loaded already !! _if i dont add that line the image loaded but the filter not work_ – mohamed momo Apr 28 '17 at 14:45
what's the value of textBox1.Text? – Tee Apr 28 '17 at 15:24
i use url of img i use this : https://trends.google.com/trends/resources/2327917647-google-icon.png – mohamed momo Apr 28 '17 at 16:01
see the edit I made to the answer – Tee Apr 28 '17 at 17:48

How to apply Filter to url load image c#

1 Answers1