Adding Data to an ASP.NET Core Website | ASP.NET Core 101 [3 of 13]


>>Hey, we’re making
an ASP.NET website in this ASP.NET 101 series, and we did a Hello World.>>Yes.>>I’m feeling pretty
successful already.>>That’s pretty great. Self-esteem.>>Self-esteem is an all time high.>>Yes.>>Let’s add some
data to our website. Now, when we last left our heroes, we had made the Contoso
Crafts website. It’s a local website, and all we did at this point was we successfully changed that code.>>Where are the crafts?>>That’s cool. We have no
crafts, that’s a problem. We also have no database.>>Not good.>>So data comes in lots
of different forms. We could make a database, we could find a website that
would give us database.>>Well. What is a database? Database is where you
store all that information that you’re going to go
and retrieve from it.>>It could be a static database, which doesn’t change very often. It could be a SQL Server. You here things like that, or SQLite. We also can use a file as a database.>>Yes. I feel like databases you can do a whole new tutorial
series just on that alone. So maybe we should focus on a file.>>We should do that. Let’s
do that will make sure that we have a database
tutorial series, but for now, let’s use
a file, good idea. So I have one on my desktop
called products.json.>>What do you know?>>So if we go over
to our application, we need to find a place to put that. I’m not really sure what the
first place to put it is.>>Well, why don’t we
make a model’s folder, and this is where we can
hold all of our products and any other related assets
or contents that we want to show the user on our site.>>Okay. So right now, we’ve got a folder here
I just right-clicked, and I said “Models”. So on the right hand side here, we’ve got a number of
different folders. You can see we’ve got pages, we’ve got wwwroot,
and we’ve got models. So I’ve got a folder
where I’ll put my models, and a model is a C# file, right?>>Yes.>>It’s going to describe what a product is or something like
that but where’s my data? Well, I’ve got this file
called product.json. You had said in the
first video that we can put things that
can be served here. I’m just going to go
and cheat a little bit, and then I click and
say “New Folder”, and I’ll just put data here.>>Make sense.>>Everyone’s system is different. I realize that this
might be non-standard or not what you’re used to
doing but it’s a way->>Yes.>>-that people can do
stuff. So this is a file.>>I’m noticing the
extension is different from the usual HTML and CSS that
we’ve been seeing recently. So this is a JSON file.>>Exactly yes. This is JSON file. So that’s JavaScript Object Notation. It’s a database. It’s basically an object that
describes the shape of some data, and we’re using it in
lieu of a database, or as the poor person’s database.>>Yes. So we can extract this
data from this JSON file, and then convert it into the kind
of object that we want to see.>>That’s a great point. In
our previous videos on C#, we talked about lists and
collections of objects. With Kendra, I did a bank, and the bank account
had transactions. With you, we’re going
to have products, and each one of these is a product, but you see that there’s
some abbreviations in there, and maybe our object will be shaped
like this and maybe it won’t.>>Also, I want to name
somethings differently.>>That’s a good point.
So let’s do this. Let’s go back to our models that
you had me make. That’s a folder.>>All right.>>I’m going to right-click
and “Add” a new class. What should we call that? We
have a bunch of products.>>Yes.>>Plural.>>Why don’t we call
it “Product” singular.>>”Product” singular. Notice this is interesting because
the folder was called Models, I ended up getting the
three name space there.>>So convenient.>>That’s cool. All right,
public class Product. Now, one thing I could do is I could actually right-click on this tab. You see this tabs that show
all of our different files? I can right-click it and I
could say New Vertical Tab. I could have it next to my thing. So I got my code here, and I got my database over
here. So I’m just going to->>That’s great.>>-put that off to the side, just
so we can hear what’s going on. All right. This is the
boring part, right?>>Yes.>>Public string Id. Yes. Exactly thank you for
looking at your watch.>>I’ve heard of something
else that exists in Visual Studio called Code Snippets, maybe if you try typing in “Prop”.>>Right, because we’re
making properties.>>Yes. You should get
a nifty the template.>>Look at that.>>Yes.>>Code Snippet for property. So prop, Tab, Tab, string, Tab, Tab, Maker, Enter, Enter, prop, Tab, Tab. Aren’t we having fun?>>Yes.>>Enter, Enter, prop, Tab, Tab URL, that’s a string. String, Tab, Tab. Yes. Now the pressure is on.>>You see when he put on your,
get to it playlist on Spotify.>>Well people are like is he
really typing or is this real. I don’t know. He’s talking
while he’s typing.>>Right.>>Int.>>Do it in your sleep.>>I don’t know we’ve
got some ratings. We’re going to talk about
ratings a little bit later. I said image though. See, look
at that I said image instead of->>That’s interesting
how are we going to make sure that’s gets
an app correctly?>>So this is a JavaScript file, and this is a C# class
that represents that data. I want to have lists of products. We need to map those two together. You’re absolutely right.
How can we do that?>>I’ve had of something
called JSON Property, which is an attribute that you can stick at the top of your property, and then map that way.>>We’ve talked about attributes
before in other videos. It’s basically a post-it note
that you stick to a property, but if I type it, it
doesn’t say anything, it doesn’t know anything about it. It’s all confused, it’s squiggly
and maybe I spelled it wrong.>>What’s going on?>>Well I can use the
light bulb and it says, look, I know about that. That’s inside system.text. Remember that we use system.this
and system.that, so helpfully, Windows Visual Studio
rather says cool, and then adds up for me. Okay.>>We call those refactoring
tools in Visual Studio.>>So that was a refactoring.>>Yes. So if you’re feeling stuck, if you see that red or
sometimes green squiggly line, then check out the light bulb that’s most likely going to be next to it because
it might be of help.>>Hopefully, the light bulb will
have something helpful for you.>>Yes.>>So I’m going to say that
the JSON property name is img. What we’re doing is
we’re mapping img image.>>Cool. Yes, because I didn’t
want to abbreviate the img.>>Yes. I don’t want the shape of my database to affect maybe
the shape of my objects. So that’s a good call.>>Another thing that I’m thinking
of back in my college days, I was always told to put a ToString
method in all of my classes.>>ToString is really interesting. Every object or most objects
in.net have a ToString. So if you’ve got a thing, you can say thing .ToString, and it gives you a nice way to
look at that object as a String. So you’re suggesting that
we go and make a public. This is interesting if you say, ToString, ToString is actually a
thing that objects already have. So we have to go and make a
public one that is an override, because objects get
a ToString for free, and we’re doing our own, aren’t we?>>Yes. We sure are.>>Okay.>>So that basically means whatever the default was for
that ToString method, we’re saying just ignore that, here’s our own version of the ToString method
that we’re going to use.>>Right. We’re overriding
that one. Okay.>>Yes.>>Now at this point, I
suppose I could go like this, and I could type in like ID plus, Maker plus, I could
use a StringBuilder.>>But that’s redundant a little bit.>>Okay.>>Ultimately, what if
you wanted to convert all this information back into
the original JSON that we want?>>That’s a good point. I would want a JSON representation of a product. So let’s go and do that,
and I can do it two ways. I can go like this, which is interesting where I
have my brackets and I could say JsonSerializer. This is another one where
they’re going to go and say yes do you want to use this.>>I think I do?>>Systematics so the helpful
light bulb, appreciate that.>>Yes.>>We’re going to serialize
it. What does serialize mean?>>Yes, that’s a lot. So serialize is you’re taking
all of this object information, and you are converting it back into the text that will
be part of the JSON file.>>Right, and serial means to do
something one after the other. So to serialize is to
go and take product and product and product and all
the properties and the properties, and one after the other
make a nice String.>>Yes.>>We’re going to serialize that, and that wants to know about our
type. That’s what this type is.>>What are we serializing?>>We talked with Kendra about
have you’ve seen the little cup, that’s a cup of tea. See. Nerd humor, loving it. So we’re going to say that
is a type of product. We are going to serialize
type of product, and then what are we
going to serialize?>>This one.>>This one here. The one we
got right here. I can do that. But when you have a message that’s
just one line, you can do this. This is cool. I just
learned about this. You don’t even need these.
You don’t even those. What?>>No brackets.>>Rocket ship.>>Oh, [inaudible] .>>Rocket ship.>>Oh, [inaudible] .>>Look you are on the rocket ship.>>What.>>So that now we can do that now. Why is it mad?>>I don’t know.>>Well, it’s mad because we’re
actually returning a String.>>Yes.>>So ToString, literally ToString. So we need to make sure we
include it as a public. It’s now in charge it
overrides everything, and it is returning a String and then we just
happened to be fancy, and we used a little rocket
ship here to make that in a single statement rather than
doing it in curly braces.>>Make sense. I believe
that’s linked syntax, that greater than or
equal terms down here?>>Yes. You’ll see that
every once in a while. I think they say it goes to, there’s lots of different ways
to phrase that but I think it’s fun to call it the rocket
ship because it looks like one.>>Yes. But it’s been shorthand
if you don’t want to take up all the space with
nothing but brackets.>>So here’s the funny part. I’m
going to go ahead and just hit Control F5 and run my application
and you’re going to note, controller five of course
start with a debugging, that it still looks exactly the same, it compiled, it didn’t
give me any errors, but it does nothing.>>Yes.>>So we’re going to need to
do another video where we actually take that data
and do something with it.>>Sounds good. We
didn’t break it though.>>We didn’t break it.>>We did something. Right.>>That’s our motto.

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