Multiselect picture gallery with winforms c#

Question

I'm trying to create a multiselect picturegallery with winforms.

Currently I have created a flowcontrolpanel that adds images as a selectablepicturebox control.

The selectablepicturebox control is a customer usercontrol that is a blank control with a picturebox and a checkbox on the top right of the picturebox. The picturebox is slightly smaller and centered in the usercontrol.

Clicking on the selectablepicturebox control will turn the background on and off indication selection.

What I want to be able to do is to select a bunch of selectablepicturebox controls and be able to capture the spacebar event to check and uncheck the checkboxes in the selected controls.

The problem is that the flowlayoutpanel never knows to capture the spacebar event.

Does anyone know away of doing this or another technology? I'm happy to use any .net based tech.

Thanks

EDIT: Here is a link to the code

Answer 1

Are you trying the KeyDown event ?

As per MSDN, This member is not meaningful for this control.

Read here & here. Instead, you may try PreviewKeyDown

Solution: [The GitHub codebase]

[Code Changes] 1. SelectablePictureBox.cs - NOTE the Set Focus

public void SetToSelected()
        {
            SelectedCheckBox.Checked = true;
            PictureHolder.Focus();
        }


private void PictureHolder_Click(object sender, EventArgs e)
        {
            BackColor = BackColor == Color.Black ? Color.Transparent : Color.Black;

            // TODO: Implement multi select features;

            if ((Control.ModifierKeys & Keys.Shift) != 0)
            {
                // Set the end selection index.
            }
            else
            {
                // Set the start selection index.
            }

            PictureHolder.Focus();
        }


// subscribe to picture box's PreviewKeyDown & expose a public event

 public event PreviewKeyDownEventHandler OnPicBoxKeyDown;
 private void OnPicBoxPrevKeyDown(object sender, PreviewKeyDownEventArgs e)
        {
            if (OnPicBoxKeyDown != null)
            {
                OnPicBoxKeyDown(sender, e);
            }
        }

[Code Changes] 1. FormMain.cs

private void FormMain_Load(object sender, EventArgs e)
        {
            SensitiveInformation sensitiveInformation = new SensitiveInformation();
            int index = 0;
            //foreach (var photo in Flickr.LoadLatestPhotos(sensitiveInformation.ScreenName))
            for (int i = 0; i < 10; i++)
            {
                SelectablePictureBox pictureBox = new SelectablePictureBox(index);

                // subscribe to picture box's event
                pictureBox.OnPicBoxKeyDown += new PreviewKeyDownEventHandler(pictureBox_OnPicBoxKeyDown);
                PictureGallery.Controls.Add(pictureBox);
                index++;
            }
        }

// this code does the selection. Query the FLowLayout control which is the 1st one and select all the selected ones
void pictureBox_OnPicBoxKeyDown(object sender, PreviewKeyDownEventArgs e)
        {
            if (e.KeyCode != Keys.Space) return;
            foreach (SelectablePictureBox item in Controls[0].Controls)
            {
                if (item.IsHighlighted)
                {
                    item.SetToSelected();
                }
            }
        }