PromptPlus

# PromptPlus ## **Slider — Operations** [![NuGet](https://img.shields.io/badge/NuGet-PromptPlus-blue)](https://www.nuget.org/packages/PromptPlus) [![License: MIT](https://img.shields.io/badge/License-MIT-yellow.svg)](https://opensource.org/licenses/MIT) [![.NET](https://img.shields.io/badge/.NET-8%20%7C%209%20%7C%2010-512BD4)](https://dotnet.microsoft.com/)

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How the Slider control behaves while it is running: keyboard, how the value steps, ranges and precision, colors and gradients, layout, history, and the details that matter in real apps.

Anatomy of the control

Select value 65                          ← prompt + live answer (same line)
Current selection: 65 %                  ← description (optional / dynamic)
0 [██████████████░░░░░░░░] 100           ← range · bar (LeftRight layout)
Left/Right: change  Enter: confirm  Esc  ← tooltip (toggle with F1 / Ctrl+F1)

The answer is written right after the prompt, on the same line — not next to the bar. It shows the current value formatted with FractionalDigits and Culture.
The range delimiters (0 … 100) and the min/max display can be hidden with HideElements.
The bar is drawn on its own line, with the character set from BarType and colored by ChangeColor / ChangeGradient.

Every region can be recolored — see Styles.

Keyboard

The keys that change the value depend on the Layout.

`LeftRight` layout (default — horizontal bar)

Key	Action
`←` / `→`	Decrease / increase by one `Step`
`Shift+Tab` / `Tab`	Decrease / increase by one `LargeStep`

`UpDown` layout (vertical, no bar)

Key	Action
`↓` / `↑`	Decrease / increase by one `Step`
`Shift+Tab` / `Tab`	Decrease / increase by one `LargeStep`

Actions (both layouts)

Key	Action
`Enter`	Confirm — returns the current value
`Esc`	Abort (when the abort key is enabled) → `IsAborted == true`, `Content == null`
`F1`	Cycle tooltip content
`Ctrl+F1`	Show / hide the tooltip

⚠️ There is no Home/End-to-min/max binding, and Page Up/Page Down do not trigger the large step — Tab/Shift+Tab do. There is also no F3 interactive history list like Input/Secret have; EnableHistory on Slider is passive — it only pre-loads the last confirmed value as the next run’s Default, nothing more.

How the value steps

Every change is clamped to the Range — you can never move below the minimum or above the maximum, but there’s no dedicated jump-to-min/max key; repeatedly pressing Tab/ Shift+Tab (or the arrow keys) is the only way there.
The arrow keys apply the small Step; Tab/Shift+Tab apply the larger LargeStep.
If you never set them, Step defaults to 1/100 of the range and LargeStep to 1/10 of the range. For the default 0..100 range that is 1 and 10.
The displayed number is rounded to FractionalDigits decimals and formatted with the active Culture (so pt-BR shows a comma separator).

💡 Choose a Step that is a meaningful increment for your domain — for example 5 for a percentage picked in fives — so keyboard navigation feels natural.

Colors & gradients

Two independent ways to color the bar:

ChangeColor(Func<double, Style>) recomputes the bar Style from the current value — ideal for thresholds (red below 30, gold above 70).
ChangeGradient(params Color[]) blends the supplied colors smoothly across the bar as the value grows.

Both react as the value changes. Use one or the other per control.

Layout differences

Layout(SliderLayout.UpDown) is more than a rotation:

Navigation moves to the Up / Down arrows.
The horizontal bar and its delimiters are hidden.
The [min,max] range display is still shown next to the answer by default — hide it too with HideElements(HideSlider.Range) if you want a bare value.
It is a compact form for tight screens or when the bar itself is not important.

The default LeftRight layout shows the full bar and uses the Left / Right arrows.

History

When EnableHistory(filename, …) is set:

Each confirmed value is persisted to the on-disk store named filename.
With Default(value, useDefaultHistory: true), the last saved value is pre-loaded as the starting position instead of value.
IHistoryOptions (expiration, max items, and so on) governs what is retained.

Unlike Input/Secret, Slider has no interactive history list — there’s no F3 hotkey and no Pagination/Selected/UnSelected history browsing UI. History here is purely passive: it just remembers the last confirmed value for next time.

You can also manage a history store directly with PromptPlus.Controls.History(filename) — add, save, or remove entries programmatically (used in the samples to seed reproducible data).

Options that change behavior

Set per instance via Options(...), or globally on PromptPlus.Config:

Option	Effect on `Slider`
`EnabledAbortKey(false)`	Removes Esc — the user must confirm
`HideAfterFinish(true)`	Erases the bar after confirm — the whole control is erased, not just the interactive part
`HideOnAbort(true)`	Erases the bar after Esc
`ShowTooltip(false)`	Hides the keyboard hint line
`Description(...)`	Overrides the description text

The global PromptPlus.Config.SliderWidth sets the default bar width; override it per control with Width.

Edge cases & gotchas

Aborted results carry Content == null, not the seeded Default. Always branch on IsAborted before reading the value.
Default must sit inside the range — a value outside min/max throws InvalidOperationException when the control runs, not ArgumentOutOfRangeException.
Precision is display + rounding — the returned value honors FractionalDigits; more decimals are not preserved beyond it.
Async description callbacks run while the prompt is open; keep them fast so stepping stays responsive.