I am trying to create a bespoke input for editform on Blazor deriving from inputbase however I am struggling to get a grasp of it as I have only recently picked up Blazor this week and C#, in general, this month.
I have foundhttps://www.meziantou.net/creating-a-inputselect-component-for-enumerations-in-blazor.htm (Or find code pasted below)and been able to use it for nullable enumarations inside of an inputselect however trying to replicate it for an input checkbox nullable has come to no avail. I was wondering if anyone has a link or would know how to tweak it to get this to work.
Thank you in advance, I will be on my computer all day virtually so feel free to ask questions, try not to berate me haha.
// file: Shared/InputSelectEnum.csusing System;using System.ComponentModel.DataAnnotations;using System.Globalization;using System.Reflection;using Humanizer;using Microsoft.AspNetCore.Components;using Microsoft.AspNetCore.Components.Forms;using Microsoft.AspNetCore.Components.Rendering;// Inherit from InputBase so the hard work is already implemented 😊// Note that adding a constraint on TEnum (where T : Enum) doesn't work when used in the view, Razor raises an error at build time. Also, this would prevent using nullable types...namespace OrderServiceFrontEnd.Shared{ public sealed class InputSelectEnum<TEnum> : InputBase<TEnum> { // Generate html when the component is rendered. protected override void BuildRenderTree(RenderTreeBuilder builder) { builder.OpenElement(0, "select"); builder.AddMultipleAttributes(1, AdditionalAttributes); builder.AddAttribute(2, "class", CssClass); builder.AddAttribute(3, "value", BindConverter.FormatValue(CurrentValueAsString)); builder.AddAttribute(4, "onchange", EventCallback.Factory.CreateBinder<string>(this, value => CurrentValueAsString = value, CurrentValueAsString, null)); // Add an option element per enum value var enumType = GetEnumType(); foreach (TEnum value in Enum.GetValues(enumType)) { builder.OpenElement(5, "option"); builder.AddAttribute(6, "value", value.ToString()); builder.AddContent(7, GetDisplayName(value)); builder.CloseElement(); } builder.CloseElement(); // close the select element } protected override bool TryParseValueFromString(string value, out TEnum result, out string validationErrorMessage) { // Let's Blazor convert the value for us 😊 if (BindConverter.TryConvertTo(value, CultureInfo.CurrentCulture, out TEnum parsedValue)) { result = parsedValue; validationErrorMessage = null; return true; } // Map null/empty value to null if the bound object is nullable if (string.IsNullOrEmpty(value)) { var nullableType = Nullable.GetUnderlyingType(typeof(TEnum)); if (nullableType != null) { result = default; validationErrorMessage = null; return true; } } // The value is invalid => set the error message result = default; validationErrorMessage = $"The {FieldIdentifier.FieldName} field is not valid."; return false; } // Get the display text for an enum value: // - Use the DisplayAttribute if set on the enum member, so this support localization // - Fallback on Humanizer to decamelize the enum member name private string GetDisplayName(TEnum value) { // Read the Display attribute name var member = value.GetType().GetMember(value.ToString())[0]; var displayAttribute = member.GetCustomAttribute<DisplayAttribute>(); if (displayAttribute != null) return displayAttribute.GetName(); // Require the NuGet package Humanizer.Core // <PackageReference Include = "Humanizer.Core" Version = "2.8.26" /> return value.ToString().Humanize(); } // Get the actual enum type. It unwrap Nullable<T> if needed // MyEnum => MyEnum // MyEnum? => MyEnum private Type GetEnumType() { var nullableType = Nullable.GetUnderlyingType(typeof(TEnum)); if (nullableType != null) return nullableType; return typeof(TEnum); } }}Blazor comp:
<InputSelectEnum @bind-Value="@_Order.IOSAppDetails.PhasedRelease"/>