btcpayserver/BTCPayServer/Views/Shared/Forms/InputElement.cshtml

@using BTCPayServer.Abstractions.Form
@using Newtonsoft.Json.Linq
@model BTCPayServer.Abstractions.Form.Field
@{
	var isInvalid = this.ViewContext.ModelState[Model.Name]?.ValidationState is Microsoft.AspNetCore.Mvc.ModelBinding.ModelValidationState.Invalid;
	var error = isInvalid ? this.ViewContext.ModelState[Model.Name].Errors[0].ErrorMessage : null;

}
<div class="form-group">
    @if (Model.Required)
    {
        <label class="form-label" for="@Model.Name" data-required>
            @Model.Label
        </label>
    }
    else
    {
        <label class="form-label" for="@Model.Name">
            @Model.Label
        </label>
    }

    <input class="form-control @(Model.IsValid() ? "" : "is-invalid")" id="@Model.Name" type="@Model.Type" required="@Model.Required" name="@Model.Name" value="@Model.Value" aria-describedby="@("HelpText" + Model.Name)"/>
	@if(isInvalid)
	{
		<span class="text-danger">@error</span>
	}
    @if (!string.IsNullOrEmpty(Model.HelpText))
    {
        <small id="@("HelpText" + Model.Name)" class="form-text text-muted">
            @Model.HelpText
        </small>
    }


</div>