|
// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
using System.Diagnostics.CodeAnalysis;
using System.Globalization;
using Microsoft.AspNetCore.Components.Rendering;
namespace Microsoft.AspNetCore.Components.Forms;
/// <summary>
/// An input component for editing numeric values.
/// Supported numeric types are <see cref="int"/>, <see cref="long"/>, <see cref="short"/>, <see cref="float"/>, <see cref="double"/>, <see cref="decimal"/>.
/// </summary>
public class InputNumber<[DynamicallyAccessedMembers(DynamicallyAccessedMemberTypes.All)] TValue> : InputBase<TValue>
{
private static readonly string _stepAttributeValue = GetStepAttributeValue();
private static string GetStepAttributeValue()
{
// Unwrap Nullable<T>, because InputBase already deals with the Nullable aspect
// of it for us. We will only get asked to parse the T for nonempty inputs.
var targetType = Nullable.GetUnderlyingType(typeof(TValue)) ?? typeof(TValue);
if (targetType == typeof(int) ||
targetType == typeof(long) ||
targetType == typeof(short) ||
targetType == typeof(float) ||
targetType == typeof(double) ||
targetType == typeof(decimal))
{
return "any";
}
else
{
throw new InvalidOperationException($"The type '{targetType}' is not a supported numeric type.");
}
}
/// <summary>
/// Gets or sets the error message used when displaying an a parsing error.
/// </summary>
[Parameter] public string ParsingErrorMessage { get; set; } = "The {0} field must be a number.";
/// <summary>
/// Gets or sets the associated <see cref="ElementReference"/>.
/// <para>
/// May be <see langword="null"/> if accessed before the component is rendered.
/// </para>
/// </summary>
[DisallowNull] public ElementReference? Element { get; protected set; }
/// <inheritdoc />
protected override void BuildRenderTree(RenderTreeBuilder builder)
{
builder.OpenElement(0, "input");
builder.AddAttribute(1, "step", _stepAttributeValue);
builder.AddAttribute(2, "type", "number");
builder.AddMultipleAttributes(3, AdditionalAttributes);
builder.AddAttributeIfNotNullOrEmpty(4, "name", NameAttributeValue);
builder.AddAttributeIfNotNullOrEmpty(5, "class", CssClass);
builder.AddAttribute(6, "value", CurrentValueAsString);
builder.AddAttribute(7, "onchange", EventCallback.Factory.CreateBinder<string?>(this, __value => CurrentValueAsString = __value, CurrentValueAsString));
builder.SetUpdatesAttributeName("value");
builder.AddElementReferenceCapture(8, __inputReference => Element = __inputReference);
builder.CloseElement();
}
/// <inheritdoc />
protected override bool TryParseValueFromString(string? value, [MaybeNullWhen(false)] out TValue result, [NotNullWhen(false)] out string? validationErrorMessage)
{
if (BindConverter.TryConvertTo<TValue>(value, CultureInfo.InvariantCulture, out result))
{
validationErrorMessage = null;
return true;
}
else
{
validationErrorMessage = string.Format(CultureInfo.InvariantCulture, ParsingErrorMessage, DisplayName ?? FieldIdentifier.FieldName);
return false;
}
}
/// <summary>
/// Formats the value as a string. Derived classes can override this to determine the formatting used for <c>CurrentValueAsString</c>.
/// </summary>
/// <param name="value">The value to format.</param>
/// <returns>A string representation of the value.</returns>
protected override string? FormatValueAsString(TValue? value)
{
// Avoiding a cast to IFormattable to avoid boxing.
switch (value)
{
case null:
return null;
case int @int:
return BindConverter.FormatValue(@int, CultureInfo.InvariantCulture);
case long @long:
return BindConverter.FormatValue(@long, CultureInfo.InvariantCulture);
case short @short:
return BindConverter.FormatValue(@short, CultureInfo.InvariantCulture);
case float @float:
return BindConverter.FormatValue(@float, CultureInfo.InvariantCulture);
case double @double:
return BindConverter.FormatValue(@double, CultureInfo.InvariantCulture);
case decimal @decimal:
return BindConverter.FormatValue(@decimal, CultureInfo.InvariantCulture);
default:
throw new InvalidOperationException($"Unsupported type {value.GetType()}");
}
}
}
|