I’m trying to select the previous image in the list view and display it in the picture box on the right. I’m using _imageIndex to keep track of what’s in the picture box currently and if it’s less than the image list length then I select the image in the list view and using the _imageIndex counter to access the image.
But it’s like it’s not getting the image index at all. It just keeps reading it at 0 and decrementing it to negative 1 and return an error when I click btnPrevious again.
System.ArgumentOutOfRangeException: 'InvalidArgument=Value of '-1' is not valid for 'index'.
Parameter name: index'
I know I set it to _imageIndex to 0 in the mnuOpen_Click event. Other than that I don’t know how to solve this. For clarity here is an image of the GUI. Ideas please?
public partial class Form1 : Form
{
string _big_fileName;
int _counter = 0;
int _imageIndex;
public Form1()
{
InitializeComponent();
}
//Displays larger instance of selected image in picture box.
private void listView1_SelectedIndexChanged(object sender, EventArgs e)
{
//FOR i is less than the first image.
for (int i = 0; i < listView1.SelectedItems.Count;i++)
{
//GET filename from listview and store in index.
_big_fileName = listView1.SelectedItems[i].Text;
//Create larger instance of image.
pictureBox1.Image = Image.FromFile(_big_fileName);
//Fill panel to the width and height of picture box.
panel1.AutoScrollMinSize = new Size(pictureBox1.Image.Width, pictureBox1.Image.Height);
}
}
private void mnuOpen_Click(object sender, EventArgs e)
{
loadImageList();
_imageIndex = 0;
}
private void btnPrevious_Click(object sender, EventArgs e)
{
if (pictureBox1.Image != null)
{
//IF Image is less than Image list size.
if (_imageIndex < imageList1.Images.Count)
{
//SELECT listview items with counter.
listView1.Items[_imageIndex].Selected = true;
//GO to previous entry.
_imageIndex--;
}
}
else
{
MessageBox.Show("No image.");
}
}
//Cycle to next image in image list and display in Picturebox.
private void btnNext_Click(object sender, EventArgs e)
{
if(pictureBox1.Image != null)
{
//IF Image is less than Image list size.
if (_imageIndex < imageList1.Images.Count)
{
listView1.Items[_imageIndex].Selected = true;
_imageIndex++;
}
}
else
{
MessageBox.Show("No image.");
}
}
private void loadImageList()
{
imageList1.Images.Clear();
listView1.Clear();
oFD1.InitialDirectory = "C:\\";
oFD1.Title = "Open an Image File";
oFD1.Filter = "JPEGS|*.jpg|GIFS|*.gif|PNGS|*.png|BMPS|*.bmp";
//Open Dialog Box.
var oldResults = oFD1.ShowDialog();
if (oldResults == DialogResult.Cancel)
{
return;
}
try
{
//GET amount of filenames.
int num_of_files = oFD1.FileNames.Length;
//Store filenames in string array.
string[] arryFilePaths = new string[num_of_files];
//FOREACH filename in the file.
foreach (string single_file in oFD1.FileNames)
{
//ACCESS array using _counter to find file.
arryFilePaths[_counter] = single_file;
//CREATE image in memory and add image to image list.
imageList1.Images.Add(Image.FromFile(single_file));
_counter++;
}
//BIND image list to listview.
listView1.LargeImageList = imageList1;
for (int i = 0; i < _counter; i++)
{
//DISPLAY filename and image from image index param.
listView1.Items.Add(arryFilePaths[i], i);
}
}
catch (Exception ex)
{
MessageBox.Show("Error " + ex.Message);
}
}
}
First of all, you're not setting _imageIndex anywhere, except in btnPrevious_Click, where you set it to 0.
You need to set it to selected index, in SelectedIndexChanged method, like this (notice the last line added to your previous code):
private void listView1_SelectedIndexChanged(object sender, EventArgs e)
{
//FOR i is less than the first image.
for (int i = 0; i < listView1.SelectedItems.Count; i++)
{
//GET filename from listview and store in index.
_big_fileName = listView1.SelectedItems[i].Text;
//Create larger instance of image.
pictureBox1.Image = Image.FromFile(_big_fileName);
//Fill panel to the width and height of picture box.
panel1.AutoScrollMinSize = new Size(pictureBox1.Image.Width, pictureBox1.Image.Height);
_imageIndex = listView1.SelectedIndices[0];
}
}
Next, in btnPreviousClick, you need to make few changes:
private void btnPrevious_Click(object sender, EventArgs e)
{
if (pictureBox1.Image != null)
{
//IF Image is less than Image list size.
if (_imageIndex >= 0 && _imageIndex < imageList1.Images.Count)
{
//De-select current item
listView1.Items[_imageIndex].Selected = false;
//GO to previous entry.
_imageIndex--;
//Select new item
if(_imageIndex>=0){
listView1.Items[_imageIndex].Selected = true;
listView1.Select();
}
}
}
else
{
MessageBox.Show("No image.");
}
}
It's necessary to call Select() method on listView1. Biggest issue was that you didn't set _imageIndex though.
Hope this is what you were looking for :)
Best regards,