PromptPlus

# PromptPlus ## **KeyPress — Methods** [](https://www.nuget.org/packages/PromptPlus) [](https://opensource.org/licenses/MIT) [](https://dotnet.microsoft.com/)

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Every fluent method on IKeyPressControl. Each returns the same control instance, so calls chain in any order. Call Run last.

The factory is PromptPlus.Controls.KeyPress(string prompt = "", string? description = null, bool showresult = false), which returns IKeyPressControl. The Confirm factory has the identical signature and returns the same interface — so every method below applies to Confirm too.

Quick jump: AddValidKey · ShowMessage · ShowMessageAsync · Styles · Options · Run

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The factory parameters

IKeyPressControl KeyPress(string prompt = "", string? description = null, bool showresult = false)

Parameter	Meaning
prompt	The prompt text shown to the user. Default empty.
description	An optional description line shown under the prompt. Default null.
showresult	When true, the pressed-key answer line stays on screen after the control finishes; when false (default) it is hidden after finish.

// Keep the answer line visible after the key is pressed
PromptPlus.Controls.KeyPress("Pick one", "Press 1 or 2", showresult: true)
    .Run();

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Restricting which keys are accepted

AddValidKey

IKeyPressControl AddValidKey(ConsoleKey key, ConsoleModifiers? requiredModifiers = null, string? displayText = null)

Registers one key (optionally with a required modifier) as an accepted input. Calls accumulate: each AddValidKey adds one more accepted combination. If you never call it, any key is accepted.

Parameter	Meaning
key	The ConsoleKey to accept.
requiredModifiers	A ConsoleModifiers that must be held at the same time (e.g. ConsoleModifiers.Control). Use null (default) to accept the key with no modifier.
displayText	An optional friendlier label shown in the tooltip instead of the raw key name.

PromptPlus.Controls.KeyPress("Press a valid key")
    .AddValidKey(ConsoleKey.A)                              // A
    .AddValidKey(ConsoleKey.B, ConsoleModifiers.Control)   // Ctrl+B
    .AddValidKey(ConsoleKey.N, null, "Off")                // N, shown as "Off"
    .AddValidKey(ConsoleKey.Y, null, "On")                 // Y, shown as "On"
    .Run();

Once one or more valid keys are registered, pressing any other key does not end the control — it triggers the invalid-key message (see below) and the control keeps waiting.

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Message for rejected keys

ShowMessage

IKeyPressControl ShowMessage(Func<ConsoleKeyInfo, string>? message)

Sets a synchronous callback that builds the error text shown when the user presses a key that is not in the accepted set. The callback receives the rejected ConsoleKeyInfo and returns the text to display. Pass null to suppress the message.

PromptPlus.Controls.KeyPress("Press a valid key")
    .AddValidKey(ConsoleKey.A)
    .AddValidKey(ConsoleKey.Y, null, "On")
    .ShowMessage(key => $"Invalid key '{key.Key}'. Try A or Y.")
    .Run();

The message is painted with KeyPressStyles.Error and clears when the next key is pressed.

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ShowMessageAsync

IKeyPressControl ShowMessageAsync(Func<ConsoleKeyInfo, CancellationToken, Task<string>>? message = null)

Asynchronous counterpart of ShowMessage, for message text that awaits I/O. The callback receives the rejected ConsoleKeyInfo and a CancellationToken tied to the control’s lifetime, and returns the text. Pass null to suppress the message. Registering an async callback replaces any synchronous one set via ShowMessage.

PromptPlus.Controls.KeyPress("Choose mode", "Only D (Debug) or R (Release)")
    .AddValidKey(ConsoleKey.D, null, "Debug")
    .AddValidKey(ConsoleKey.R, null, "Release")
    .ShowMessageAsync(async (key, cancellationToken) =>
    {
        await Task.Delay(80, cancellationToken);
        return $"'{key.Key}' is not valid. Use D or R.";
    })
    .Run();

⚠️ The async callback is awaited synchronously (blocking) on the UI thread — it does not run in parallel with the render loop. Keep it fast; long calls freeze the prompt until they return.

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Appearance & behavior

Styles

IKeyPressControl Styles(KeyPressStyles styleType, Style style)

Overrides the color of one visual region of this control instance. See the full region list and examples on the Styles page.

using PromptPlusLibrary;
using ConsolePlusLibrary;   // Color, Style live here

PromptPlus.Controls.KeyPress("Styled sample")
    .Styles(KeyPressStyles.Prompt, new Style(Color.Yellow, Color.Default))
    .Run();

Throws ArgumentNullException if style is null.

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Options

IKeyPressControl Options(Action<IControlOptions> configureOptions)

Overrides global behaviors (PromptPlus.Config) for this one control — prompt/description text, abort key, tooltip visibility, hide-after-finish, and the extra-info affixes.

PromptPlus.Controls.KeyPress("Continue?")
    .Options(o => o
        .EnabledAbortKey(false)     // no Esc for this prompt
        .ShowTooltip(true)
        .HideAfterFinish(false))    // keep the UI after a key is pressed
    .Run();

See Global Behaviors → Per-Control Override for the complete IControlOptions list. Throws ArgumentNullException if configureOptions is null.

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Running the control

Run

ResultPrompt<ConsoleKeyInfo?> Run(CancellationToken cancellationToken = default)

Renders the prompt and blocks until the user presses an accepted key or aborts (Esc). Returns a ResultPrompt<ConsoleKeyInfo?> — read .Content.HasValue before .Content.Value.

Parameter	Meaning
cancellationToken	A CancellationToken that cancels the wait while the control waits for input.

using var cts = new CancellationTokenSource(TimeSpan.FromSeconds(30));
var result = PromptPlus.Controls.KeyPress("Press any key").Run(cts.Token);

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See also

• Operations — how these methods behave at runtime
• Styles — the KeyPressStyles regions
• Index — overview and method map
• Confirm → Methods — the same API, pre-set for yes/no

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