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How to use Tabs in ASP.NET CORE

By Jacob
I want to show Components in a tabs , so first of all create few components. In this project we have three components, First View Component  public class AllViewComponent : ViewComponent     {         private readonly UserManager<ApplicationUser> _userManager;         public AllViewComponent(UserManager<ApplicationUser> userManager)         {             _userManager = userManager;         }         public async Task<IViewComponentResult> InvokeAsync()         {             List<StudentViewModel> allUsers = new List<StudentViewModel>();             var items = await _userManager.Users.ToListAsync();             foreach (var item in items)             {                 allUsers.Add(new StudentViewModel {Id=item.Id, EnrollmentNo = item.EnrollmentNo, FatherName = item.FatherName, Name = item.Name, Age = item.Age, Birthdate = item.Birthdate, Address = item.Address, Gender = item.Gender, Email = item.Email });             }            
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fix parameters dictionary contains a null entry

By Jacob

Introduction

Basically that's type of error occurs due to null value. But i have already try to pass some value, manually in the controller function. Always i get this error. Ok let's start to story of the error. I want to get the record from single department table and that's name is hyperlinked. Now, When i click to any hyperlink then open respective employee details, which is stored in another table. What i was done. First i was write the code for retrieving the value from single data base table, on that time, my code run successfully. But in Next time when i wrote the code for retrieving the record from two database table, on that time, i got the error.

What steps i have taken

  1. First step to prepare classes for employee and department
  2. Second step to create a context for both class
  3. third step to prepare a controller for department, as well as prepare view for department
  4. forth step to prepare controller for employee, as well as prepare view for employee.

Error

The parameters dictionary contains a null entry for parameter 'deptid' of non-nullable type 'System.Int32' for method 'System.Web.Mvc.ActionResult linkEmp(Int32)' in 'WebApplication10.Controllers.EmployeeController'. An optional parameter must be a reference type, a nullable type, or be declared as an optional parameter. Parameter name: parameters.

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How to fix it

Prepare the seperate Context class for each model. I have two class that is employee and department , If you want to retrieve data from both class then you want to make two seperate context for each. I have two context that is 1. EmployeeContext 2. DepartmentContext
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How to use Tabs in ASP.NET CORE

By Jacob
I want to show Components in a tabs , so first of all create few components. In this project we have three components, First View Component  public class AllViewComponent : ViewComponent     {         private readonly UserManager<ApplicationUser> _userManager;         public AllViewComponent(UserManager<ApplicationUser> userManager)         {             _userManager = userManager;         }         public async Task<IViewComponentResult> InvokeAsync()         {             List<StudentViewModel> allUsers = new List<StudentViewModel>();             var items = await _userManager.Users.ToListAsync();             foreach (var item in items)             {                 allUsers.Add(new StudentViewModel {Id=item.Id, EnrollmentNo = item.EnrollmentNo, FatherName = item.FatherName, Name = item.Name, Age = item.Age, Birthdate = item.Birthdate, Address = item.Address, Gender = item.Gender, Email = item.Email });             }            
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Polynomial representation using Linked List for Data Structure in 'C'

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Print the asp.net webpage using button

By Jacob
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