Add the name space in your controller at the top
using Microsoft.AspNet.Identity;
Wherever you need to get the user id use the following code in your controller
string userId = User.Identity.GetUserId();
Add the name space in your controller at the top
using Microsoft.AspNet.Identity;
Wherever you need to get the user id use the following code in your controller
string userId = User.Identity.GetUserId();
It is just a method that will return a string which can contain any content you wan from a simple string to a table of data.
method that returns a string. The string can represent any type of content that you want. For example, you can use HTML Helpers to render standard HTML tags like HTML <input>
and <img>
tags. In ASP.NET we have many standard HTML Helpers
In a web page we need to list the features of a product.
If the feature is present then show a Tick
If the feature is missing then show a Cross
As shown below.
This is achieved by using two different CSS classes which will render the Tick or the Cross
When I use my CSS class “plain” it will render a Cross
When I use the class “checked” it shows a Tick.
Now in razor view you would typically use the
@Html.DisplayFor(model => model.Alarm) which would render a standard check box ( if true then the checkbox will be ticked and if false the checkbox will be empty) But we want a better display hence we want to make use of our CSS classes.
In order to show the customised CSS we will have to write some logic in the Razor view which is not preferred at all as we would like to keep the logic out from the views and secondly it will need a lot of code as for each item we will have to use some kind of If loop as shown below.
Not recommended
@if (Model.AirConditioning == true)
{
<li class=”ticked”>@Html.LabelFor(model => model.AirConditioning)</li> }
else
{
<li class=”plain”>@Html.LabelFor(model => model.AirConditioning)</li> }
Let us write a Custom HTML Helper for it.
Create a Class
I created a folder called HTMLHelpers in my project and then created a class called myHTMLHelpers.cs as shown below
using System; using System.Collections.Generic; using System.Linq; using System.Web; namespace myapplication.Helpers { public static class myHTMLHelpers { public static IHtmlString TickOrCross(bool content) { string htmlString = ""; if(content==true) { htmlString = String.Format("checked"); // if content is true then we want the CSS class checked } else { htmlString = String.Format("plain"); // if content is falsethen we want the CSS class plain } return new HtmlString(htmlString); } } }
How te make use of this HTML Helper ?
Go to your Razor View
at the top of the page add the namespace under which we created our helper class
@using myapplication.Helpers
at the right place in your razor view I have made use of our custom html helper.
We pass the model value to it and it will set the class name accordingly to display a Tick or a Cross
<ul class=”span2″>
<li class=”@myHTMLHelpers.TickOrCross(Model.AirConditioning)“>Air Conditioning</li>
<li class=”@myHTMLHelpers.TickOrCross(Model.Alarm)“>Alarm</li>
</ul>
The other way would have been to put the logic into the view using the if block in our code,. which is not a good practice.
@if (Model.AirConditioning == true)
{
<li class=”ticked”>Air Conditioning</li> }
else
{
<li class=”plain”>Air Conditioning</li>
}
The easiest way to render an HTML link in is to use the HTML.ActionLink() helper.
With MVC, the Html.ActionLink() does not link to a view. It creates a link to a controller action.
The first parameter is the link text, and the second parameter is the name of the controller action.
The Html.ActionLink() helper above, outputs the following HTML:
When using @html.actionlink it normally renders it like a hyperlink. But there is a simple way to render it as a button.
@Html.ActionLink("Register,"Register")
and it will render it as a Hyperlink
I am using Boostrap so I have the CSS class called “btn” available. Otherwise you can use your own CSS which can create a button
@Html.ActionLink("Register", "Register" ,null, new { @class = "btn" })
@Html.ActionLink("Register", "Register" ,null, new with {.class = "btn" })
the null is for the Routevalues ( in the example we are using any route values hence null)
Hope this helps you
Problem description:
If you are getting the error while running your MVC4 application in VB.NET
You must call the “WebSecurity.InitializeDatabaseConnection” method before you call any other method of the “WebSecurity” class.
Solution
Add the following line in the GLOBAL.ASX
Ensure that you are using the correct connection string and other information as per your own application as shown in the highlighted line above.
Scenario: If you have two controllers with the same name in different areas, then you would end up with errors as shown below, while there are numerous examples available on the web but it took me a while to figure out the correct solution for VB.
Hope it help you and saves you time.
Problem Description
I have a HOME controller in my MVC4 application and then I created a new AREA called SUPERADMIN. I then created a HOME controller in that area as well.I received the following error.
Solution:
1. Fix the Route.Config in your MVC4 project under APP_Start folder. See the yellow coloured text,
vbnull is for constraints( so we are not adding special constraints
the next one “RealEstateVB” is the namespace , RealEstateVB is the name of my application and is taken as the default namespace.
2. Now Go to your AREA. I had an area called SUPERADMIN.
See the highlighted text. You have to define the namespace. eg. I have used “RealEstateVB.Areas.Superadmin for my SuperAdmin area.
Also make a note how I have added superadmin in front of the /{controller}/{action}/{id}
This should get your project going without any errors. For each area you have you will need to fix the xxxAreaRegistration.vb file as described in the above step(2)
Here is a simple way to do the role based Authorization in your MVC4 Controllers using VB.NET
IF you have a role called Client then simply add the following text on top of your each ActionResult( which displays the view)
<Authorize(Roles:=”Client”)>
See the following example. The Index View has been restricted and can only be viewed by someone in the Client role.
<Authorize(Roles:="Client")>
Function Index() As ActionResult
Return View(db.Purchasers.ToList())
End Function
If you want to password protect some pages on your MVC4 site using the Forms Authentication then it is best to to protect the whole site and then selectively allow Anonymous Access to the pages which are to be shown to every visitor.
Open the FilterConfig.VB file and add the line
filters.Add(New AuthorizeAttribute) in it
Once you run your application you would see that all the pages of your website are now protected, the users have to register before they can access.
Imports System.Web Imports System.Web.Mvc
Public Class FilterConfig
Public Shared Sub RegisterGlobalFilters(ByVal filters As GlobalFilterCollection)
filters.Add(New HandleErrorAttribute())
filters.Add(New AuthorizeAttribute)
End Sub
End Class
If you need to allow some pages for anonymous view then add the following decoration.
<AllowAnonymouse()> on each page which you want to open up for anonymous access.
<AllowAnonymous()>
Function Index() As ActionResult
ViewData("Message") = "Modify this template to jump-start your ASP.NET MVC application."
Dim rep As New RepositoryRealEstate
ViewBag.AgentCount = rep.GetAgentsCount
ViewBag.ProperyCount = rep.GetPropertyCount
ViewBag.VendorCount = rep.getvendorcount
Return View()
End Function
There are numerous example for C3 but I had to spend quite some time to adapt it to my project using VB.NET
Hope it can be of help to you.
I assume that you have
already added the GridMVC package from NUGET.
Here are step by step guide
Controller
No change needed , see a sample below,
Function Index() As ActionResult
Return View(db.Categories.ToList())
End Function
View
Add the following import at the top of your view
@imports GridMVC.html
You would need to reference the following also
Add the stylesheets (check the location after you install the GridMVC package)
<link href=”~/Content/Gridmvc.css” rel=”stylesheet” />
<link href=”~/Content/gridmvc.datepicker.min.css” rel=”stylesheet” />
For your paging support
Install the PagedList package also
Once you have installed this package then add the following reference to your view, this will help you format your paging buttons
properly.
<link href=”~/Content/PagedList.css” rel=”stylesheet” />
Add the following code for your Grid to appear – In the following examples my Model has three fields – CatId, CatName
and ParentCatId. Make changes to suit your needs.
@Html.Grid(Model).Columns(Function(columns)
columns.Add(Function(o) o.CatID).Titled(“Cat #“).SetWidth(40)
columns.Add(Function(o) o.CatName).Titled(“Category“).SetWidth(100)
columns.Add(Function(o) o.ParentCatID).Titled(“Parent Cat #“).SetWidth(40)
End Function
).WithPaging(10).Sortable(True)
In your Create Actions in a Controller in MVC4, if you try to save text with html tags then you get this annoying error.
A potentially dangerous Request.Form value was detected from the client
Description: ASP.NET has detected data in the request that is potentially dangerous because it might include HTML markup or script. The data might represent an attempt to compromise the security of your application, such as a cross-site scripting attack. If this type of input is appropriate in your application, you can include code in a web page to explicitly allow it. For more information, see http://go.microsoft.com/fwlink/?LinkID=212874.
This is a great protection if you do not want your client to save html text.
Here is how to get rid of this error
In the following example we have a create action which saves a new record. MVC4 controller will have two functions.
The first function is for GET ( this is the one which will render the page to save the new record
The second function is for POST. This function is responsible to receive the model
which has been populated by the data which the user has filled in on the form. We have to add the following text
<ValidateInput(False)>
for C# add
[ValidateInput(false)]
‘ GET: /admin/ManageAds/Create
Function Create() As ActionResult
Return View()
End Function
‘ POST: /admin/ManageAds/Create
<HttpPost()> _
<ValidateAntiForgeryToken()> _
<ValidateInput(False)>
Function Create(ByVal ad As Ad) As ActionResult
If ModelState.IsValid Then
db.Ads.Add(ad)
db.SaveChanges()
Return RedirectToAction(“Index”)
End If
Return View(ad)
End Function
How to allow File Downloads in MVC4 using VB.NET
We are using an ActionResult instead of FileResult.
Function download(id as Integer) As ActionResult
The reason is that if use the FileResult and your file does not exist then it will show a blank page, instead of this
we are using an ActionResult which is more versatile.
We can return the actual FileResult if the file exists
and in case of an error we can return a View (if we used a FileResult
Function download(id as Integer) As ActionResult
‘ In this example we are using the id to pick up the actual file from a model
Dim SoundFile as SoundFile = db.SoundFiles.Find(id)
Dim path As String = Server.MapPath(“~/myLocation/” & SoundFile.MP3File)
‘get file object as FileInfo
Dim fileinfo As System.IO.FileInfo = New System.IO.FileInfo(path)‘– if the file exists on the server
If fileinfo.Exists Then
rep.IncrementDownloadCount(id) ‘This is my routine to count the downloads, you will not need it
Return File(path, “application/octet-stream”, fileinfo.Name)
Else
Return View(“Error”)
End IfEnd Function