Multi tool use

Displaying an Image from Azure Storage before downloading - C#

I'm writing a program that will allow the user to download selected images from Azure Blob Storage.

I have it working, however, currently, the images are downloaded to a file and then this file path is used to display the images. I want the images to be displayed and then allow the user to select which images can be downloaded.

Below is my code for downloading the images.

for (int i = 1; i<=dira.ListBlobs().Count(); i++)
{
try
{
CloudBlob blob = dira.GetBlobReference(i + ".png");
blob.DownloadToFile(localFilePath + "/" + i.ToString() + ".png", FileMode.Create);
// MessageBox.Show(i.ToString());
}
catch (StorageException ex)
{
}
}


Then my code for displaying the downloaded image is here:

pictureBox1.BackgroundImage= Image.FromFile(filePath + ".png");


How would I display the images before they have been downloaded?

CloudBLob

PictureBox.Location

3 Answers
3

As you said above, we can download them to memory.

Here is simple code for your reference:

CloudBlob blob = dira.GetBlobReference(i + ".png");
MemoryStream memoryStream = new MemoryStream();
blob.DownloadToStream(memoryStream);
pictureBox1.BackgroundImage = System.Drawing.Image.FromStream(memoryStream);


If you want to really save some network traffic (aka time to download) between PC and Blob storage all you have to do is create thumbnail in Azure.

I found a very nice and complete example how to do that.
Mechanism is pretty neat and 'cloudy'

Please bear in mind, that above could raise your Azure bill. As in other cases in this too you need to consider what are your priorities:

I need to be super quick and save network for my users -> create thumbnails in Azure

I want to save costs on my side and performance is not a concern -> download full sized image and create thumbnail on host

You can not show images without downloading it

But instead,

You should create a thumbnail image with your actual image so when you show the list to a user you can download thumbnails from the server and then actual images on user selection

you can create thumbnail using below code

public static System.Drawing.Bitmap ResizeImage(System.Drawing.Image image, int width, int height)
{
//a holder for the result
Bitmap result = new Bitmap(width, height);

//use a graphics object to draw the resized image into the bitmap
using (Graphics graphics = Graphics.FromImage(result))
{
//set the resize quality modes to high quality
graphics.CompositingQuality = System.Drawing.Drawing2D.CompositingQuality.HighQuality;
graphics.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.HighQualityBicubic;
graphics.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.HighQuality;
//draw the image into the target bitmap
graphics.DrawImage(image, 0, 0, result.Width, result.Height);
}

//return the resulting bitmap
return result;
}


Ref:- C# Creating thumbnail

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