BinaryImageComboBox

Initialises a new image combo box in ListStyle.Standard style, with no images and no items.

The control is a DropDownList that draws from Imagelist (UseImageListForComboBox is true); set Imagelist or Bitmaps next.

Gets or sets the bitmaps the items' images are drawn from: bitmap n beside item n.

Setting it also sets UseImageListForComboBox to false. Set BitmapsAssociatedText to the matching text, in the same order. Available in code only; in the designer use Imagelist.

Gets or sets the text of each item, in the same order as Bitmaps; setting it replaces the Items of the list.

Setting an array clears Items and adds one item for each string. Setting null leaves Items as they are. Available in code only.

Gets or sets the colour of the frame drawn round each item's image.

Used while DrawRectangleAroundImage is true. The frame is one logical pixel wide, just outside the image; the disabled control draws it in SystemColors.ControlDark.

Gets or sets what the control lists: your own images and text, the computer's drives, or the installed fonts.

ListStyle.DriveList replaces the items with an entry for the computer itself followed by every drive, each with its shell icon and display name, selects the first, and raises DriveSelectionChanged as the user picks.

ListStyle.FontList replaces the items with the name of every installed font family that has a regular style, unsorted, and selects the first. Each name is drawn in the control's font or in its own typeface, as FontDisplayStyle says.

Both set the control's font to Microsoft Sans Serif 9 point, and the list is built when the property is set, so set it again to pick up a drive or font added since. Setting ListStyle.Standard afterwards clears the items: refill them, or set BitmapsAssociatedText again.

var fontPicker = new BinaryImageComboBox { Location = new Point(12, 12), Width = 240 };
fontPicker.ComboListStyle = ListStyle.FontList;
fontPicker.FontDisplayStyle = FontNameDisplayStyle.DisplayUsingFontFamilyName;
fontPicker.SelectedIndexChanged += (sender, e) =>
    previewBox.Font = new Font(fontPicker.SelectedItem.ToString(), 12f);
Controls.Add(fontPicker);

Gets or sets the height of the space each item's image is drawn in.

Until this is set, the rows keep the height the combo box gives them for its font, and an image taller than a row is drawn smaller to fit. Setting it makes every row tall enough for an image of this height with two logical pixels above and below it, or for a line of text if that is taller, and the closed control grows with the rows.

Windows limits a combo box row to 255 device pixels; on a display scaled far enough for a row to reach that, the images are drawn smaller to fit, keeping their shape. The drive and font lists size their own rows.

Gets or sets the width of the space each item's image is drawn in.

An image keeps its shape: it is scaled to fit the box this property and DesiredHeightForDrawingTheImages describe, and centred in it. Every item keeps this space, with or without an image, and the text starts after it.

Gets or sets whether a frame is drawn round each item's image.

Turn it off for icons with transparent backgrounds, which look better unframed.

Gets the style of the control, which is always DropDownList: the user picks from the list and cannot type.

Gets or sets whether a font list draws each font's name in that font, or all of them in the control's own font.

Applies in ListStyle.FontList style. Drawing each name in its own typeface is the more useful preview, but symbol fonts then show symbols rather than a readable name.

Gets or sets the image list the items' images are drawn from: image n beside item n.

Setting it also sets UseImageListForComboBox to true. The text comes from Items, which you fill yourself; an item beyond the last image is drawn without one.

The images are drawn at the size of the image box (DesiredWidthForDrawingTheImages by DesiredHeightForDrawingTheImages), not at ImageList.ImageSize, so give the list an image size at least that large for sharp pictures on high-DPI displays.

var icons = new ImageList { ImageSize = new Size(32, 32), ColorDepth = ColorDepth.Depth32Bit };
icons.Images.Add(cardIcon);
icons.Images.Add(bankTransferIcon);
icons.Images.Add(invoiceIcon);

paymentMethodPicker.Imagelist = icons;
paymentMethodPicker.Items.AddRange(new object[] { "Card", "Bank transfer", "Invoice" });
paymentMethodPicker.SelectedIndex = 0;

Gets the items of the list – the text shown beside each image.

Setting BitmapsAssociatedText, or switching ComboListStyle, replaces the items. In the designer the items are saved with the form.

Gets or sets which image source the items are drawn with: Imagelist, or Bitmaps.

Setting Imagelist sets this to true, and setting Bitmaps sets it to false, so it rarely needs setting by hand. While the chosen source is empty, a click does not open the list.

Releases the resources the control uses.

The images in Imagelist and Bitmaps belong to the application and are not disposed.

Returns the text shown for one item when the control is bound to a data source: the item's DisplayMember value.

The item's display text; the object's own ToString text when there is no display member; or an empty string when there is no data source, the item does not exist, or (for a list of objects) the property is not a string.

Raises the Control.DpiChangedAfterParent event and sizes the rows again for the new display scale.

Raises the Control.FontChanged event and sizes the rows again, so they stay tall enough for the text.

Prepares the new window, and sizes the rows for the images when DesiredHeightForDrawingTheImages has been set.

Raises the Control.KeyDown event; for Alt+Down and Alt+Up it raises DropDownAboutToBeShown first, and a handler that cancels stops the key there.

Raises the Control.KeyUp event, first raising DropDownAboutToBeShown when the Alt key is part of the key combination.

Sets the height of each row of a drive list to the system's small icon size plus two logical pixels, and raises the ComboBox.MeasureItem event for it.

In the other styles the event is not raised and the rows keep the height already set.

Raises the ComboBox.SelectedIndexChanged event; an exception thrown by a handler is absorbed rather than propagated.

Draws one item – its image, the image's frame and its text – in the list or on the closed control, or a drive or font entry in those styles.

Redraws the selected item – image and text – on the closed control.

Draws the disabled control: the selected item with its image greyed and half transparent, and its frame and text in the system's dimmed colours.

Processes Windows messages, raising DropDownAboutToBeShown when the user clicks the control, and keeping a click from opening the list while there is no image source.

Occurs when the user picks a different entry in a drive list, with the details of the drive picked.

Raised only in ListStyle.DriveList style. The first entry is the computer itself, whose DriveInformation.DrivePathString is empty; check it before using the path.

drivePicker.ComboListStyle = ListStyle.DriveList;
drivePicker.DriveSelectionChanged += (sender, drive) =>
{
    if (drive.DrivePathString.Length == 0)
        return;   // the "This PC" entry

    folderList.Items.Clear();
    folderList.Items.AddRange(Directory.GetDirectories(drive.DrivePathString));
    Text = drive.DriveDisplayName + " - " + drive.DriveTypeString;
};

Occurs when the user is about to open the list – by clicking the control, or pressing Alt+Down or Alt+Up – and lets the handler stop it.

Set the handler's cancelNow argument to true to keep the list closed. The event can be raised more than once for one gesture, so keep the handler free of side effects such as message boxes.

paymentMethodPicker.DropDownAboutToBeShown += (object sender, ref bool cancelNow) =>
{
    cancelNow = orderIsLocked;   // the payment method cannot change once the order is invoiced
};