KryptonSplitButton

Overview

KryptonSplitButton is a KryptonDropButton that is always a split: the button body raises Click (and executes KryptonCommand), and the chevron raises DropDown then shows KryptonContextMenu or ContextMenuStrip.

It lives in Krypton.Toolkit. Rendering, palettes, and menu positioning are unchanged from KryptonDropButton.

Why a dedicated type

Split behaviour already existed in two other places:

Type Default Typical use
KryptonButton No chevron Push button. ShowSplitOption = true is the legacy opt-in.
KryptonDropButton Chevron + splitter Split by default. Splitter = false makes the whole button a drop-down.
KryptonSplitButton Always split Toolbox type for “Save + menu” (WinForms SplitButton / ToolStripSplitButton).

ShowSplitOption is kept for compatibility. Prefer KryptonSplitButton for new UI.

Krypton.Toolkit.Utilities KryptonMiniToolbarSplitButton is a mini-toolbar item, not this control.

Architecture

VisualSimpleBase
  └── KryptonDropButton          // Splitter optional; mnemonic opens menu when Splitter is true
        ├── KryptonButton        // DropDown/Splitter off; ShowSplitOption re-enables both
        │     └── KryptonCheckButton
        └── KryptonSplitButton   // Splitter locked on; mnemonic fires Click

KryptonSplitButton is a sibling of KryptonButton, not a subclass. KryptonDropButton used to special-case this is KryptonButton for click routing and WM_CONTEXTMENU. Those are now virtuals:

  • OpensDropDownOnNonSplitterClick — true on drop-down; false on KryptonButton
  • SuppressSystemContextMenu — true on drop-down / split; false on KryptonButton
  • MnemonicPerformsDropDown — follows Splitter on drop-down; false on KryptonSplitButton

Splitter is virtual. The split-button override always returns true and ignores false.

Accessibility: KryptonSplitButtonAccessibleObject advertises AccessibleRole.SplitButton. Default action is still Press (PerformClick).

Designer: reuses KryptonDropButtonDesigner. The smart tag omits Splitter when the component is a KryptonSplitButton.

Public API

public class KryptonSplitButton : KryptonDropButton
{
    public KryptonSplitButton();

    // Always true. Hidden. Setting false is ignored.
    public override bool Splitter { get; set; }
}

Inherited (the ones that matter for consumers):

  • Click / PerformClick() — button body
  • DropDown / PerformDropDown() — chevron
  • KryptonContextMenu, ContextMenuStrip
  • DropDownPosition, DropDownOrientation
  • KryptonCommand — executed from OnClick (body), not from the chevron
  • Values, palettes, ButtonStyle, badges, pulsing border

There is no ShowSplitOption on this type. There is no WinForms-style DefaultItem (last menu item becomes the caption) in v1.

Usage

var save = new KryptonSplitButton
{
    Values = { Text = "&Save" },
    KryptonContextMenu = menu // items: Save, Save As, Save All
};
save.Click += (_, _) => SaveDocument();

Designer: drop KryptonSplitButton from the Toolbox, assign KryptonContextMenu, handle Click.

Mnemonic (&Save / Alt+S) fires Click, not the menu. That differs from KryptonDropButton with Splitter = true, where the mnemonic opens the drop-down.

Edge cases

  • Casting to KryptonDropButton and setting Splitter = false still leaves the splitter on (virtual override).
  • KryptonButton.ShowSplitOption is unchanged, including mnemonic → drop-down when the splitter is on.
  • Do not change KryptonDropButton.Splitter default (true); that would be breaking.
  • Right-click system context menu is suppressed (same as KryptonDropButton). Attach KryptonContextMenu for the chevron.
  • net472 / C# 7.3 only.