Everytime I try to submit the form to create a new boat I get the System.NullReferenceException: 'Object reference not set to an instance of an object.' error.
This is the code in question, the boat model:
using SQLite;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
namespace MauiAVDApp2.Models
{
public class Boat
{
[PrimaryKey, AutoIncrement]
public int? BoatId { get; set; }
public string? BoatName { get; set; }
public string? BoatDescription { get; set; }
public string? BoatCity { get; set; }
public BoatType BoatType { get; set; }
public string? BoatManufacturer { get; set; }
public string? BoatModel { get; set; }
public string? BoatImage { get; set; }
public int? BoatSeats { get; set; }
public double? BoatPrice { get; set; }
public Boolean? BoatWithSkipper { get; set; }
public Boolean? BoatWithLicense { get; set; }
public double? BoatLatitude { get; set; }
public double? BoatLongitude { get; set; }
public double? BoatDistance { get; set; }
//public Host BoatHost { get; set; }
}
}
The boatservice:
using MauiAVDApp2.Models;
using SQLite;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
namespace MauiAVDApp2.Services
{
internal class BoatService : IBoatService
{
private SQLiteAsyncConnection _dbConnection;
public BoatService()
{
}
private async void SetupDb()
{
if (_dbConnection == null)
{
string dbPath = Path.Combine(Environment.GetFolderPath(Environment.SpecialFolder.LocalApplicationData), "BoatApplication.db3");
_dbConnection = new SQLiteAsyncConnection(dbPath);
await _dbConnection.CreateTableAsync<Boat>();
}
}
public async Task<int> AddBoat(Boat boat)
{
return await _dbConnection.InsertAsync(boat);
}
public async Task<int> DeleteBoat(Boat boat)
{
return await _dbConnection.DeleteAsync(boat);
}
public async Task<List<Boat>> GetBoatListAsync(Boat boat)
{
var boatList = await _dbConnection.Table<Boat>().ToListAsync();
return boatList;
}
public async Task<int> UpdateBoat(Boat boat)
{
return await _dbConnection.UpdateAsync(boat);
}
}
}
The iboatservice:
using MauiAVDApp2.Models;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
namespace MauiAVDApp2.Services
{
internal interface IBoatService
{
Task<List<Boat>> GetBoatListAsync(Boat boat);
Task<int> AddBoat(Boat boat);
Task<int> UpdateBoat(Boat boat);
Task<int> DeleteBoat(Boat boat);
}
}
The blazor component:
@page "/add-boat"
@using MauiAVDApp2.Services
@using MauiAVDApp2.Models
@inject IBoatService boatService
<h3>Add Boat</h3>
<div class="container">
<div class="row">
<form @onsubmit="FormSubmit">
<div class="mb-3">
<label for="exampleInputName1" class="form-label">Name:</label>
<input type="text" class="form-control" id="exampleInputName1" placeholder="Bautista" aria-describedby="nameHelp" @bind="boat.BoatName">
</div>
<div class="mb-3">
<label for="form-select" class="form-label">Choose boat type</label>
<select class="form-select" id="form-select" aria-label="Default select example" @bind="boat.BoatType">
<option value="0">Choose your boat type</option>
@foreach (var boatType in Enum.GetValues(typeof(BoatType)))
{
if ((int)boatType == (int)boat.BoatType)
{
<option value="@((int)boatType)" selected>@boatType</option>
}
else
{
<option value="@((int)boatType)">@boatType</option>
}
}
</select>
</div>
<div class="mb-3">
<label for="exampleInpuDescription1" class="form-label">Description:</label>
<input type="text" class="form-control" id="exampleInputDescription1" placeholder="Bestes boat ever" @bind="boat.BoatDescription">
</div>
<div class="mb-3">
<label for="exampleInputCity1" class="form-label">City:</label>
<input type="text" class="form-control" placeholder="Amsterdam" id="exampleInputCity1" @bind="boat.BoatCity">
</div>
<div class="mb-3">
<label for="exampleInpuDescription1" class="form-label">Manufacturer:</label>
<input type="text" class="form-control" placeholder="Yamaha" id="exampleInputDescription1" @bind="boat.BoatManufacturer">
</div>
<div class="mb-3">
<label for="exampleInpuDescription1" class="form-label">Model</label>
<input type="text" class="form-control" placeholder="GXR" id="exampleInputDescription1" @bind="boat.BoatModel">
</div>
<div class="mb-3">
<label for="exampleInpuDescription1" class="form-label">Image</label>
<input type="text" class="form-control" placeholder="https//:www.google.com/ray-bautista" id="exampleInputDescription1" @bind="boat.BoatImage">
</div>
<div class="mb-3">
<label for="exampleInpuDescription1" class="form-label">Seats</label>
<input type="number" class="form-control" placeholder="3" id="exampleInputDescription1" @bind="boat.BoatSeats">
</div>
<div class="mb-3">
<label for="exampleInpuDescription1" class="form-label">Price</label>
<input type="number" class="form-control" placeholder="3.00" id="exampleInputDescription1" @bind="boat.BoatPrice">
</div>
<div class="form-check form-switch">
<input class="form-check-input" type="checkbox" role="switch" id="flexSwitchCheckChecked" @bind="boat.BoatWithSkipper">
<label class="form-check-label" for="flexSwitchCheckChecked">With Skipper</label>
</div>
<div class="form-check form-switch">
<input class="form-check-input" type="checkbox" role="switch" id="flexSwitchCheckChecked" @bind="boat.BoatWithLicense">
<label class="form-check-label" for="flexSwitchCheckChecked">Customer needs license</label>
</div>
<button type="submit" class="btn btn-primary mt-3 d-block">Submit</button>
</form>
</div>
</div>
@code {
Boat boat = new Boat();
private async void FormSubmit()
{
var response = await boatService.AddBoat(boat);
if (response > 0)
{
boat.BoatSeats = 0;
boat.BoatPrice = 0.00;
boat.BoatWithLicense = boat.BoatWithSkipper = false;
boat.BoatCity = boat.BoatManufacturer = boat.BoatImage = boat.BoatDescription = boat.BoatModel = boat.BoatName = string.Empty;
await App.Current.MainPage.DisplayAlert("form submit invoked", "form submitted", "OK");
}
else
{
await App.Current.MainPage.DisplayAlert("Boat was not created", "Something went wrong, try again", "OK");
}
}
}
I've seen similar questions about System.NullReferenceException: 'Object reference not set to an instance of an object.'
But never about an on submit case, hence why I am asking this question now.
All help is much appreciated!
