create fixed size thumbnail dynamically on listview control

Question

how to create fixed size thumbnail dynamically and resize image in listview best fit the size of the thumbnail.

private void Treeview1_AfterSelect(System.Object sender, System.Windows.Forms.TreeViewEventArgs e)
{
    if (folder != null && System.IO.Directory.Exists(folder))
                {
                    try
                    {

                        DirectoryInfo dir = new DirectoryInfo(@folder);
                        foreach (FileInfo file in dir.GetFiles())
                        {
                            try
                            {
                                imageList.ImageSize = new Size(136, 136);
                                imageList.ColorDepth = ColorDepth.Depth32Bit;
                                Image img = new Bitmap(Image.FromFile(file.FullName));                                    
                                Graphics g = Graphics.FromImage(img);

                                g.DrawRectangle(Pens.Red, 0, 0, img.Width - 21, img.Height - 21);
                                //g.DrawRectangle(Pens.Red, 0, 0, img.Width, img.Height);                                                                                                                                                
                                imageList.Images.Add(img);
                            }
                            catch
                            {
                                Console.WriteLine("This is not an image file");
                            }     
                        }


                        for (int j = 0; j < imageList.Images.Count; j++)
                        {
                            this.ListView1.Items.Add("Item" + j);
                            this.ListView1.Items[j].ImageIndex = j;
                        }

                        this.ListView1.View = View.LargeIcon;
                        this.ListView1.LargeImageList = imageList;
                        //this.ListView1.DrawItem += new DrawListViewItemEventHandler(ListView1_DrawItem);                                                       

                        //import(folder);
                    }
                    catch (Exception ex)
                    {
                    }
}

score 0 · Accepted Answer · edited May 23 '17 at 12:19

I have code in this answer specifically for resizing images along with resolution:

public void GenerateThumbNail(HttpPostedFile fil, string sPhysicalPath, 
                              string sOrgFileName,string sThumbNailFileName,
                              ImageFormat oFormat, int rez)
{

    try
    {

        System.Drawing.Image oImg = System.Drawing.Image.FromStream(fil.InputStream);

        decimal pixtosubstract = 0;
        decimal percentage;

        //default
        Size ThumbNailSizeToUse = new Size();
        if (ThumbNailSize.Width < oImg.Size.Width || ThumbNailSize.Height < oImg.Size.Height)
        {
            if (oImg.Size.Width > oImg.Size.Height)
            {
                percentage = (((decimal)oImg.Size.Width - (decimal)ThumbNailSize.Width) / (decimal)oImg.Size.Width);
                pixtosubstract = percentage * oImg.Size.Height;
                ThumbNailSizeToUse.Width = ThumbNailSize.Width;
                ThumbNailSizeToUse.Height = oImg.Size.Height - (int)pixtosubstract;
            }
            else
            {
                percentage = (((decimal)oImg.Size.Height - (decimal)ThumbNailSize.Height) / (decimal)oImg.Size.Height);
                pixtosubstract = percentage * (decimal)oImg.Size.Width;
                ThumbNailSizeToUse.Height = ThumbNailSize.Height;
                ThumbNailSizeToUse.Width = oImg.Size.Width - (int)pixtosubstract;
            }

        }
        else
        {
            ThumbNailSizeToUse.Width = oImg.Size.Width;
            ThumbNailSizeToUse.Height = oImg.Size.Height;
        }

        Bitmap bmp = new Bitmap(ThumbNailSizeToUse.Width, ThumbNailSizeToUse.Height);
        bmp.SetResolution(rez, rez);
        System.Drawing.Image oThumbNail = bmp;

        bmp = null;

        Graphics oGraphic = Graphics.FromImage(oThumbNail);

        oGraphic.CompositingQuality = CompositingQuality.HighQuality;

        oGraphic.SmoothingMode = SmoothingMode.HighQuality;

        oGraphic.InterpolationMode = InterpolationMode.HighQualityBicubic;

        Rectangle oRectangle = new Rectangle(0, 0, ThumbNailSizeToUse.Width, ThumbNailSizeToUse.Height);

        oGraphic.DrawImage(oImg, oRectangle);

        oThumbNail.Save(sPhysicalPath  + sThumbNailFileName, oFormat);

        oImg.Dispose();

    }
    catch (Exception ex)
    {
        Response.Write(ex.Message);
    }

}

create fixed size thumbnail dynamically on listview control

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