ROUTING WITH CUSOMT OPTIONS
1. program.cs
Add this middleware
app.MapContorller()
2. Contorller
Add [Route(“URL”)] above the method which needs to be called for that url
Ex [Route(“home”]
Public IActionResult Data(){ return View() } → this will show view related to home
[Route(“home/about”)]
Public IActionResult RandomName(){ return View() } ⇒ swill show about page
Adding [Route(“Home”)] above Contrl class, will help by elimantig the home name from other
routes below
I.e [Route(“Home”)]
Public class Homecntr : Cntrl{
[Route(“”)]
Public IActionResult Index(){ return View() }
[Route(“about”)]
Public IActionResult About(){ return View() }
}
MAP FOR ROUTING
Map(“/Home”, ()=> “Hello from Home”); - wrks w all mthds
MapGet(“/Home”, ()=> “Hello from Home get”); wrks w only get
MapPost(“/Home”, ()=> “Hello from Home post”); wrks w only post
MapPut(“/Home”, ()=> “Hello from Home put”); wrks w only put
MapDelete(“/Home”, ()=> “Hello from Home del”); wrks w only del method
Routing using UseRouting()
app.UseRouting();
app.UseEndpoints(endpoint => {
endpoint.MapGet(‘/Home”, async (cntx) =>
{ await cntx.Response.WriteAsync(‘this works “); }
endpoint.MapPut(“/Home”, async (cntx)=>
{ await cntx.Response.Wreitasync(“tis wrks”); }
} );
});
localhost:port/ < — in this case this code wl execute
app.Run( async ( HttpCntx cntx ) =>
{
Await cntx.Response.WriteAsync(‘First page w/o any appended url”);
}
RAZOR
Inline expressions starts with @
Enclose code blacks betwen @{ and }
Vars are decl with var keyword
Enclose strings in quotation marks
Layout View = Master Page – starts w _ naming convection - _Layout.cshtml
What is Master Page ?
Header
Center data → content changes
Footer
Common view is defined on master page, and changin are made separately and master
pg is connected to those separate files, via child relation. I.e index pg is child of master
pg, and Master pg is parent of index pg. We use Layout Property in child pages.
Master pg
<body>
<header>ahha</header>
@RenderBody()
<footer>asdf</footer>
</body>
Index pg
@{ Layout = “~/path to master pg “; }
<h2> this is index pg </h2>
Thats how yo connect child Indepg to parent Masterpg
PASSING DATE FROM CNTRL TO VIEW
4 METHODS - ViewData, ViewBag, TempData, StronglyTypedViews
1.VIEWDATA —
ViewData[“Key”] = <Value>; in cntrl
Ex ViewData[“data1”] = “program”;
@ViewData[“Key”] in Razor or view
Ex @ViewData[‘data1’]
For sending arrays
String[[ arr = {“adsf”,”afd”,”adf”};
ViewData[‘data3’] = arr;
In View, @{ foreach( var itm in (string[])ViewData[‘data3’])
{ <h2> @itm </h2> } }
So we type casted here, since razor wasnt able to figure out the data type w/o it
This data becomes null if view is changed, i.e abouts view wont work in contact view
2. VIEWBAG —-
ViewBag.<PropertyName> = <Value>;
Property – string and Value – string, obj, int, list, anything …
ViewBag.data1 = “ahha”;
@ViewBag.data1
Not type casting needed in this alike in viewdata, so we dont need to mention typ of
Value while using it or accessing it, below src
Viewbag and viewdata, can be interchgned in cntr and view
I.e cntr → ViewBag.data = “ads”; view– @ViewData[“data”] will work and viceversa
Data is lost in veiwbag alike in viewdata when view changed.
3.TempData
TempData[“data”] = “accs”; → cntrl
@TempData[‘data”] → view
This data can be used only with one view, any view across webapp, i.e made in index
cntr bt used in contact view is possible, bt than it cant be used in anyother view.
To get it kept, apply TempData.Keep( empty or keys ) at end of cntr program, this way
the value will be maintained across multiple views. Session concept makes this easy.
MODELS
Repository pattern
We make an extra class where we process the data between cntr and db data
This is loosely coupling and adds abstraction layer
In repository folder make a class exgtending IStudent
Public class studRepo : IStudent {
Public List<StudentMode> getAllstd(){ return alldata() }
Public StudentModel getstdbyId( int id ) { return alldata().Where( x => x.id == id ); }
Private List< Strudmode > alldata(){ fetched from db }
In cntrl mention the repo
Private readonly StudentRepositort _stdrepo = null;
Create its obj in constructor to access its method in cntrl
PASSING DATA OF MODEL TO VIEW FROM CNTRL USING VIEWDATA N OTHR…
THEN WRITE RAZOR IN VIEW FILES
4.STRONGLY TYPED VIEW
Used to send db data usually to view, ie Model obj are sent
Ex model emp initiated in cntrl, obj is fed vals and sent to view
This obj is recvd in view liek this
@model path.emp
@*<he> @Model.empId </h2> *@
If list of obj sent to view than use this way …
view
cntr
model
TAG HELPER
ADD IN VIEWIMPORTS FILE
@addTagHelper *, Microsoft.AspNetCore.Mvc.TagHelpers
This it can be used anywhere in asp app, line 4 is w/ tag helpers
MODEL BINDING
[Htpp Request]
Needs to be added above cntrlr action method
FORM VALIDATIONS
[Required] [StringLength] [EmailAddress] [Range] [RegularExpression]
[Compare] [Phone] [Url]
ENTITY FRAMEWORK - USED TO DB CNNECTIVITY
Step1 - all below install
TOOLS - migrations and automating Dbcntx
Design - design time logic
Step 2 - make model class
And Dbcntxt class
Dbcntrx is integral part of EF, we use in app to interafct with db, manages conn
STEP 3 - Create a Connection String in appsetings.json file
STEP 4 - Registering conn str in program.cs
Step 5 - Add migration and run migration
SESSION
Used to maintain state of vars,
STEP 1 - builder.Services.AddSession(); add this before build AND
app.UseSesson(); middleware
STEP 2 - Create session variable in cntrl
Using Microsoft.Aspnetcore.Http
HttpContext.Session.SetString(“KEY”,”value”);
STEP 3 - ACCESS SESSION VAR in actn methods by
HttpContext.Session.GetString(“KET”);
STEP 4 - To access session directly in view, use HttpContextAccessor
For this add in program.cs
builder.Services.AddSingleton<IHttpContextAccessor, HttpContextAccessor>()
And write this in view
DROPDOWN
BINDING MULTIPLE MODELS TO A VIEW
We can only bind one model to a view at a time, for multiple models, we put those
each models into a list, make a view which takes in list and add these lists into
that models list and than bind that model to the view and access the vals using
object operator
PARTIAL VIEWS
Its imp concept, kinda used for making SPA apps.Recom syntax of naming file is
starting name w underscore _Name.cshtml. We hv to insert it into main view to use.
Rest at shared folder. Multiple PV can be inserted in main view.
<partial name=”_Filename”/> —-> add this line in any view where u want PV to be.
TYPES 1. STATIC 2. DYNAMIC
PV WITH MODEL ( ALSO CALLED DYNAMIC PV )
We bind a model to our PV and than use that PV across diff views
THIS IS CNTRL CLASS SENDING DATA TO VIEW
THIS IS CNTRL VIEW
SAME VIEW, USING PV, SENDING THEM DATA RCVD FROM CNTRL
THIS IS PV BINDED TO MODEL PRODUCT
