private void BuildComponent <FValue>(RenderTreeBuilder builder, FieldData fieldData)
{
FValue value = (FValue)fieldData.PropertyInfo.GetValue(Model);
// build up the access method
var constant = Expression.Constant(Model, Model !.GetType());
var exp = Expression.Property(constant, fieldData.Name);
var valueExpression = Expression.Lambda <Func <FValue> >(exp);
// build the event callback, include a notification that the field has updated as well as the model
var valueChanged =
Microsoft.AspNetCore.Components.CompilerServices.RuntimeHelpers.TypeCheck(
EventCallback.Factory.Create <FValue?>(
this,
EventCallback.Factory.CreateInferred(
this,
__value =>
{
fieldData.PropertyInfo.SetValue(Model, __value);
ModelChanged.InvokeAsync(Model);
},
value
)
)
);
// put our surrogate component in the render pipeline
// parsing in the needed variable that will be loading into it as params by the infrastructure (magic)
var elementType = typeof(PlaceHolderComponent <FValue>);
builder.OpenComponent(0, elementType);
builder.AddAttribute(1, nameof(PlaceHolderComponent <FValue> .FieldData), fieldData);
builder.AddAttribute(2, nameof(PlaceHolderComponent <FValue> .Value), value);
builder.AddAttribute(3, nameof(PlaceHolderComponent <FValue> .ValueExpression), valueExpression);
builder.AddAttribute(4, nameof(PlaceHolderComponent <FValue> .ValueChanged), valueChanged);
builder.AddAttribute(5, nameof(PlaceHolderComponent <FValue> .ReadOnly), ReadOnly);
builder.AddAttribute(6, nameof(PlaceHolderComponent <FValue> .UseValidationMessages), UseValidationMessages);
builder.CloseComponent();
}