ASP.NET core MVC オプション検索を作成する

PM> Install-Package -ProjectName プロジェクト名 -Id Microsoft.EntityFrameworkCore.SqlServer
PM> Install-Package -ProjectName プロジェクト名 -Id Microsoft.EntityFrameworkCore.Tools

PM> Scaffold-DbContext -Provider Microsoft.EntityFrameworkCore.SqlServer -Connection "Data Source=192.168.xxx.xxx;Database=hoge;user id=sa;password=password" -f -OutputDir "Models" -Context "MemberDbContext" -UseDatabaseNames -DataAnnotations

//        protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder)
//        {
//            if (!optionsBuilder.IsConfigured)
//            {
//#warning To protect potentially sensitive information in your connection string, you should move it out of source code. You can avoid scaffolding the connection string by using the Name= syntax to read it from configuration - see https://go.microsoft.com/fwlink/?linkid=2131148. For more guidance on storing connection strings, see http://go.microsoft.com/fwlink/?LinkId=723263.
//                optionsBuilder.UseSqlServer("Data Source=192.168.xxx.xxx;Database=hoge;user id=sa;password=password");
//            }
//        }

{
  "Logging": {
    "LogLevel": {
      "Default": "Information",
      "Microsoft.AspNetCore": "Warning"
    }
  },
  "AllowedHosts": "*",
  "ConnectionStrings": {
    "DefaultConnection": "Server=192.168.xxx.xxx;Database=hoge;User ID=sa;Password=password;"
  }
}

var builder = WebApplication.CreateBuilder(args);

// Add services to the container.
builder.Services.AddControllersWithViews();

// 追加
builder.Services.AddDbContext<MemberDbContext>(
    options => options.UseSqlServer(
        builder.Configuration.GetConnectionString("DefaultConnection")
        )
    );

using System;
using System.Collections.Generic;
using System.ComponentModel.DataAnnotations;
using System.ComponentModel.DataAnnotations.Schema;
using Microsoft.AspNetCore.Mvc.Rendering;
using Microsoft.EntityFrameworkCore;

namespace aspcoremvc.Models
{    
    public partial class memberViewModel
    {
        public List<member> member { get; set; }
        public int id { get; set; }
        public int department { get; set; }
        public string year { get; set; } = null!;
        public SelectList month { get; set; }
        public int employee { get; set; }        
        public DateTime created_data { get; set; }        
        public DateTime updated_data { get; set; }
        public string memberSerch { get; set; }
        
    }
}

        public async Task<IActionResult> Index(string memberSerch,string strSearch)
        {
            // 全てのmonth取得
            IQueryable<string> all = from m in _context.members
                                            orderby m.month
                                            select m.month;

            // 全データ取得
            var member = from m in _context.members
                         select m;

            // オプション設定時の処理
            if (!string.IsNullOrEmpty(memberSerch))
            {
                member = member.Where(x => x.month == memberSerch);
            }

            // 各プロパティを作成
            var memberList = new memberViewModel
            {
                month = new SelectList(await all.Distinct().ToListAsync()),
                member = await member.ToListAsync()
            };

            return View(memberList);
        }

@model aspcoremvc.Models.memberViewModel

@{
    ViewData["Title"] = "Index";
}

<h1>Index</h1>

<p>
    <a asp-action="Create">Create New</a>
</p>
<form asp-controller="members" asp-action="Index" method="get">
    <div class="row">
        <div class="col">
            <select class="form-select" asp-for="memberSerch" asp-items="Model.month">
                <option value="">全て</option>
            </select>
        </div>
        <div class="col">
            <input class="btn btn-primary" type="submit" value="検索" />
        </div>
    </div>
</form>
<table class="table">
    <thead>
        <tr>
            <th>
                @Html.DisplayNameFor(model => model.department)
            </th>
            <th>
                @Html.DisplayNameFor(model => model.year)
            </th>
            <th>
                @Html.DisplayNameFor(model => model.month)
            </th>
            <th>
                @Html.DisplayNameFor(model => model.employee)
            </th>
            <th>
                @Html.DisplayNameFor(model => model.created_data)
            </th>
            <th>
                @Html.DisplayNameFor(model => model.updated_data)
            </th>
            <th></th>
        </tr>
    </thead>
    <tbody>
@foreach (var item in Model.member) {
        <tr>
            <td>
                @Html.DisplayFor(modelItem => item.department)
            </td>
            <td>
                @Html.DisplayFor(modelItem => item.year)
            </td>
            <td>
                @Html.DisplayFor(modelItem => item.month)
            </td>
            <td>
                @Html.DisplayFor(modelItem => item.employee)
            </td>
            <td>
                @Html.DisplayFor(modelItem => item.created_data)
            </td>
            <td>
                @Html.DisplayFor(modelItem => item.updated_data)
            </td>
            <td>
                <a asp-action="Edit" asp-route-id="@item.id">Edit</a> |
                <a asp-action="Details" asp-route-id="@item.id">Details</a> |
                <a asp-action="Delete" asp-route-id="@item.id">Delete</a>
            </td>
        </tr>
}
    </tbody>
</table>