常連

[パート 6: ASP.NET Core のコントローラーのメソッドとビュー](https://docs.microsoft.com/ja-jp/aspnet/core/tutorials/first-mvc-app/controller-methods-views?view=aspnetcore-6.0)

decimal変換でエラーが発生しています。

エラー内容
```
InvalidCastException: Unable to cast object of type 'System.String' to type 'System.Decimal'.
Microsoft.Data.SqlClient.SqlBuffer.get_Decimal()
lambda_method35(Closure , QueryContext , DbDataReader , ResultContext , SingleQueryResultCoordinator )
Microsoft.EntityFrameworkCore.Query.Internal.SingleQueryingEnumerable<T>+AsyncEnumerator.MoveNextAsync()
Microsoft.EntityFrameworkCore.EntityFrameworkQueryableExtensions.ToListAsync<TSource>(IQueryable<TSource> source, CancellationToken cancellationToken)
Microsoft.EntityFrameworkCore.EntityFrameworkQueryableExtensions.ToListAsync<TSource>(IQueryable<TSource> source, CancellationToken cancellationToken)
MvcMovie.Controllers.MoviesController.Index() in MoviesController.cs
+
              return _context.Movie != null ? 
Microsoft.AspNetCore.Mvc.Infrastructure.ActionMethodExecutor+TaskOfIActionResultExecutor.Execute(IActionResultTypeMapper mapper, ObjectMethodExecutor executor, object controller, object[] arguments)
System.Threading.Tasks.ValueTask<TResult>.get_Result()
System.Runtime.CompilerServices.ValueTaskAwaiter<TResult>.GetResult()
Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker.<InvokeActionMethodAsync>g__Awaited|12_0(ControllerActionInvoker invoker, ValueTask<IActionResult> actionResultValueTask)
Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker.<InvokeNextActionFilterAsync>g__Awaited|10_0(ControllerActionInvoker invoker, Task lastTask, State next, Scope scope, object state, bool isCompleted)
Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker.Rethrow(ActionExecutedContextSealed context)
Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker.Next(ref State next, ref Scope scope, ref object state, ref bool isCompleted)
Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker.<InvokeInnerFilterAsync>g__Awaited|13_0(ControllerActionInvoker invoker, Task lastTask, State next, Scope scope, object state, bool isCompleted)
Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.
```

MovieController.cs
```C#
using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;
using Microsoft.AspNetCore.Mvc;
using Microsoft.AspNetCore.Mvc.Rendering;
using Microsoft.EntityFrameworkCore;
using MvcMovie.Data;
using MvcMovie.Models;

namespace MvcMovie.Controllers
{
    public class MoviesController : Controller
    {
        private readonly MvcMovieContext _context;

        public MoviesController(MvcMovieContext context)
        {
            _context = context;
        }

        // GET: Movies
        public async Task<IActionResult> Index()
        {
              return _context.Movie != null ? 
                          View(await _context.Movie.ToListAsync()) :
                          Problem("Entity set 'MvcMovieContext.Movie'  is null.");
        }

        // GET: Movies/Details/5
        public async Task<IActionResult> Details(int? id)
        {
            if (id == null || _context.Movie == null)
            {
                return NotFound();
            }

            var movie = await _context.Movie
                .FirstOrDefaultAsync(m => m.Id == id);
            if (movie == null)
            {
                return NotFound();
            }

            return View(movie);
        }

        // GET: Movies/Create
        public IActionResult Create()
        {
            return View();
        }

        // POST: Movies/Create
        // To protect from overposting attacks, enable the specific properties you want to bind to.
        // For more details, see http://go.microsoft.com/fwlink/?LinkId=317598.
        [HttpPost]
        [ValidateAntiForgeryToken]
        public async Task<IActionResult> Create([Bind("Id,Title,ReleaseDate,Genre,Price")] Movie movie)
        {
            if (ModelState.IsValid)
            {
                _context.Add(movie);
                await _context.SaveChangesAsync();
                return RedirectToAction(nameof(Index));
            }
            return View(movie);
        }

        // GET: Movies/Edit/5
        public async Task<IActionResult> Edit(int? id)
        {
            if (id == null || _context.Movie == null)
            {
                return NotFound();
            }

            var movie = await _context.Movie.FindAsync(id);
            if (movie == null)
            {
                return NotFound();
            }
            return View(movie);
        }

        // POST: Movies/Edit/5
        // To protect from overposting attacks, enable the specific properties you want to bind to.
        // For more details, see http://go.microsoft.com/fwlink/?LinkId=317598.
        [HttpPost]
        [ValidateAntiForgeryToken]
        public async Task<IActionResult> Edit(int id, [Bind("Id,Title,ReleaseDate,Genre,Price")] Movie movie)
        {
            if (id != movie.Id)
            {
                return NotFound();
            }

            if (ModelState.IsValid)
            {
                try
                {
                    _context.Update(movie);
                    await _context.SaveChangesAsync();
                }
                catch (DbUpdateConcurrencyException)
                {
                    if (!MovieExists(movie.Id))
                    {
                        return NotFound();
                    }
                    else
                    {
                        throw;
                    }
                }
                return RedirectToAction(nameof(Index));
            }
            return View(movie);
        }

        // GET: Movies/Delete/5
        public async Task<IActionResult> Delete(int? id)
        {
            if (id == null || _context.Movie == null)
            {
                return NotFound();
            }

            var movie = await _context.Movie
                .FirstOrDefaultAsync(m => m.Id == id);
            if (movie == null)
            {
                return NotFound();
            }

            return View(movie);
        }

        // POST: Movies/Delete/5
        [HttpPost, ActionName("Delete")]
        [ValidateAntiForgeryToken]
        public async Task<IActionResult> DeleteConfirmed(int id)
        {
            if (_context.Movie == null)
            {
                return Problem("Entity set 'MvcMovieContext.Movie'  is null.");
            }
            var movie = await _context.Movie.FindAsync(id);
            if (movie != null)
            {
                _context.Movie.Remove(movie);
            }
            
            await _context.SaveChangesAsync();
            return RedirectToAction(nameof(Index));
        }

        private bool MovieExists(int id)
        {
          return (_context.Movie?.Any(e => e.Id == id)).GetValueOrDefault();
        }
    }
}

```

SeedData.cs

```C#
using Microsoft.EntityFrameworkCore;
using Microsoft.Extensions.DependencyInjection;
using MvcMovie.Data;
using System;
using System.Linq;

namespace MvcMovie.Models
{
    public static class SeedData
    {
        public static void Initialize(IServiceProvider serviceProvider)
        {
            using (var context = new MvcMovieContext(
                serviceProvider.GetRequiredService<
                    DbContextOptions<MvcMovieContext>>()))
            {
                // Look for any movies.
                if (context.Movie.Any())
                {
                    return;   // DB has been seeded
                }

                context.Movie.AddRange(
                    new Movie
                    {
                        Title = "When Harry Met Sally",
                        ReleaseDate = DateTime.Parse("1989-2-12"),
                        Genre = "Romantic Comedy",
                        Price = 7.99M
                    },

                    new Movie
                    {
                        Title = "Ghostbusters ",
                        ReleaseDate = DateTime.Parse("1984-3-13"),
                        Genre = "Comedy",
                        Price = 8.99M
                    },

                    new Movie
                    {
                        Title = "Ghostbusters 2",
                        ReleaseDate = DateTime.Parse("1986-2-23"),
                        Genre = "Comedy",
                        Price = 9.99M
                    },

                    new Movie
                    {
                        Title = "Rio Bravo",
                        ReleaseDate = DateTime.Parse("1959-4-15"),
                        Genre = "Western",
                        Price = 3.99M
                    }
                );
                context.SaveChanges();
            }
        }
    }
}
```

Movie.cs
```
using System;
using System.ComponentModel.DataAnnotations;
using System.ComponentModel.DataAnnotations.Schema;

namespace MvcMovie.Models
{
    public class Movie
    {
        public int Id { get; set; }
        public string? Title { get; set; }

        [Display(Name = "Release Date")]
        [DataType(DataType.Date)]
        public DateTime ReleaseDate { get; set; }
        public string? Genre { get; set; }

        [Column(TypeName = "decimal(18, 2)")]
        public decimal? Price { get; set; }
    }
}
```
イメージ追記：
![イメージ説明](https://ddjkaamml8q8x.cloudfront.net/questions/2022-08-29/f7161d91-f1e1-4f23-b357-ed7b9448d541.png)


[パート 6: ASP.NET Core のコントローラーのメソッドとビュー](https://docs.microsoft.com/ja-jp/aspnet/core/tutorials/first-mvc-app/controller-methods-views?view=aspnetcore-6.0)

decimal変換でエラーが発生しています。

エラー内容
```
InvalidCastException: Unable to cast object of type 'System.String' to type 'System.Decimal'.
Microsoft.Data.SqlClient.SqlBuffer.get_Decimal()
lambda_method35(Closure , QueryContext , DbDataReader , ResultContext , SingleQueryResultCoordinator )
Microsoft.EntityFrameworkCore.Query.Internal.SingleQueryingEnumerable<T>+AsyncEnumerator.MoveNextAsync()
Microsoft.EntityFrameworkCore.EntityFrameworkQueryableExtensions.ToListAsync<TSource>(IQueryable<TSource> source, CancellationToken cancellationToken)
Microsoft.EntityFrameworkCore.EntityFrameworkQueryableExtensions.ToListAsync<TSource>(IQueryable<TSource> source, CancellationToken cancellationToken)
MvcMovie.Controllers.MoviesController.Index() in MoviesController.cs
+
              return _context.Movie != null ? 
Microsoft.AspNetCore.Mvc.Infrastructure.ActionMethodExecutor+TaskOfIActionResultExecutor.Execute(IActionResultTypeMapper mapper, ObjectMethodExecutor executor, object controller, object[] arguments)
System.Threading.Tasks.ValueTask<TResult>.get_Result()
System.Runtime.CompilerServices.ValueTaskAwaiter<TResult>.GetResult()
Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker.<InvokeActionMethodAsync>g__Awaited|12_0(ControllerActionInvoker invoker, ValueTask<IActionResult> actionResultValueTask)
Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker.<InvokeNextActionFilterAsync>g__Awaited|10_0(ControllerActionInvoker invoker, Task lastTask, State next, Scope scope, object state, bool isCompleted)
Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker.Rethrow(ActionExecutedContextSealed context)
Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker.Next(ref State next, ref Scope scope, ref object state, ref bool isCompleted)
Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker.<InvokeInnerFilterAsync>g__Awaited|13_0(ControllerActionInvoker invoker, Task lastTask, State next, Scope scope, object state, bool isCompleted)
Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.
```

MovieController.cs
```C#
using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;
using Microsoft.AspNetCore.Mvc;
using Microsoft.AspNetCore.Mvc.Rendering;
using Microsoft.EntityFrameworkCore;
using MvcMovie.Data;
using MvcMovie.Models;

namespace MvcMovie.Controllers
{
    public class MoviesController : Controller
    {
        private readonly MvcMovieContext _context;

        public MoviesController(MvcMovieContext context)
        {
            _context = context;
        }

        // GET: Movies
        public async Task<IActionResult> Index()
        {
              return _context.Movie != null ? 
                          View(await _context.Movie.ToListAsync()) :
                          Problem("Entity set 'MvcMovieContext.Movie'  is null.");
        }

        // GET: Movies/Details/5
        public async Task<IActionResult> Details(int? id)
        {
            if (id == null || _context.Movie == null)
            {
                return NotFound();
            }

            var movie = await _context.Movie
                .FirstOrDefaultAsync(m => m.Id == id);
            if (movie == null)
            {
                return NotFound();
            }

            return View(movie);
        }

        // GET: Movies/Create
        public IActionResult Create()
        {
            return View();
        }

        // POST: Movies/Create
        // To protect from overposting attacks, enable the specific properties you want to bind to.
        // For more details, see http://go.microsoft.com/fwlink/?LinkId=317598.
        [HttpPost]
        [ValidateAntiForgeryToken]
        public async Task<IActionResult> Create([Bind("Id,Title,ReleaseDate,Genre,Price")] Movie movie)
        {
            if (ModelState.IsValid)
            {
                _context.Add(movie);
                await _context.SaveChangesAsync();
                return RedirectToAction(nameof(Index));
            }
            return View(movie);
        }

        // GET: Movies/Edit/5
        public async Task<IActionResult> Edit(int? id)
        {
            if (id == null || _context.Movie == null)
            {
                return NotFound();
            }

            var movie = await _context.Movie.FindAsync(id);
            if (movie == null)
            {
                return NotFound();
            }
            return View(movie);
        }

        // POST: Movies/Edit/5
        // To protect from overposting attacks, enable the specific properties you want to bind to.
        // For more details, see http://go.microsoft.com/fwlink/?LinkId=317598.
        [HttpPost]
        [ValidateAntiForgeryToken]
        public async Task<IActionResult> Edit(int id, [Bind("Id,Title,ReleaseDate,Genre,Price")] Movie movie)
        {
            if (id != movie.Id)
            {
                return NotFound();
            }

            if (ModelState.IsValid)
            {
                try
                {
                    _context.Update(movie);
                    await _context.SaveChangesAsync();
                }
                catch (DbUpdateConcurrencyException)
                {
                    if (!MovieExists(movie.Id))
                    {
                        return NotFound();
                    }
                    else
                    {
                        throw;
                    }
                }
                return RedirectToAction(nameof(Index));
            }
            return View(movie);
        }

        // GET: Movies/Delete/5
        public async Task<IActionResult> Delete(int? id)
        {
            if (id == null || _context.Movie == null)
            {
                return NotFound();
            }

            var movie = await _context.Movie
                .FirstOrDefaultAsync(m => m.Id == id);
            if (movie == null)
            {
                return NotFound();
            }

            return View(movie);
        }

        // POST: Movies/Delete/5
        [HttpPost, ActionName("Delete")]
        [ValidateAntiForgeryToken]
        public async Task<IActionResult> DeleteConfirmed(int id)
        {
            if (_context.Movie == null)
            {
                return Problem("Entity set 'MvcMovieContext.Movie'  is null.");
            }
            var movie = await _context.Movie.FindAsync(id);
            if (movie != null)
            {
                _context.Movie.Remove(movie);
            }
            
            await _context.SaveChangesAsync();
            return RedirectToAction(nameof(Index));
        }

        private bool MovieExists(int id)
        {
          return (_context.Movie?.Any(e => e.Id == id)).GetValueOrDefault();
        }
    }
}

```

SeedData.cs

```C#
using Microsoft.EntityFrameworkCore;
using Microsoft.Extensions.DependencyInjection;
using MvcMovie.Data;
using System;
using System.Linq;

namespace MvcMovie.Models
{
    public static class SeedData
    {
        public static void Initialize(IServiceProvider serviceProvider)
        {
            using (var context = new MvcMovieContext(
                serviceProvider.GetRequiredService<
                    DbContextOptions<MvcMovieContext>>()))
            {
                // Look for any movies.
                if (context.Movie.Any())
                {
                    return;   // DB has been seeded
                }

                context.Movie.AddRange(
                    new Movie
                    {
                        Title = "When Harry Met Sally",
                        ReleaseDate = DateTime.Parse("1989-2-12"),
                        Genre = "Romantic Comedy",
                        Price = 7.99M
                    },

                    new Movie
                    {
                        Title = "Ghostbusters ",
                        ReleaseDate = DateTime.Parse("1984-3-13"),
                        Genre = "Comedy",
                        Price = 8.99M
                    },

                    new Movie
                    {
                        Title = "Ghostbusters 2",
                        ReleaseDate = DateTime.Parse("1986-2-23"),
                        Genre = "Comedy",
                        Price = 9.99M
                    },

                    new Movie
                    {
                        Title = "Rio Bravo",
                        ReleaseDate = DateTime.Parse("1959-4-15"),
                        Genre = "Western",
                        Price = 3.99M
                    }
                );
                context.SaveChanges();
            }
        }
    }
}
```

Movie.cs
```
using System;
using System.ComponentModel.DataAnnotations;
using System.ComponentModel.DataAnnotations.Schema;

namespace MvcMovie.Models
{
    public class Movie
    {
        public int Id { get; set; }
        public string? Title { get; set; }

        [Display(Name = "Release Date")]
        [DataType(DataType.Date)]
        public DateTime ReleaseDate { get; set; }
        public string? Genre { get; set; }

        [Column(TypeName = "decimal(18, 2)")]
        public decimal? Price { get; set; }
    }
}
```

@@ -280,3 +280,6 @@
     }
 }
 ```
+イメージ追記：
+![イメージ説明](https://ddjkaamml8q8x.cloudfront.net/questions/2022-08-29/f7161d91-f1e1-4f23-b357-ed7b9448d541.png)

質問編集履歴