Multiple rows updation in sql server

Use EF Core, for example in the following I take the liberty to change column names. Not sure why CurrentQuantity is a decimal and not an int but left it as is.

CREATE TABLE [dbo].[Products](
	[Id] [INT] IDENTITY(1,1) NOT NULL,
	[ProductName] [NVARCHAR](MAX) NULL,
	[CurrentQuantity] [DECIMAL](10, 2) NULL,
 CONSTRAINT [PK_Products] PRIMARY KEY CLUSTERED 
(
	[Id] ASC
)WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON, OPTIMIZE_FOR_SEQUENTIAL_KEY = OFF) ON [PRIMARY]
) ON [PRIMARY] TEXTIMAGE_ON [PRIMARY]

EF Core code generated by EF Power Tools.

Find full source here

EF Core model

public partial class Products : INotifyPropertyChanged
{
    private string _productName;
    private decimal? _currentQuantity;
    public int Id { get; set; }

    public string ProductName
    {
        get => _productName;
        set
        {
            if (value == _productName) return;
            _productName = value;
            OnPropertyChanged();
        }
    }

    public decimal? CurrentQuantity
    {
        get => _currentQuantity;
        set
        {
            if (value == _currentQuantity) return;
            _currentQuantity = value;
            OnPropertyChanged();
        }
    }

    public event PropertyChangedEventHandler PropertyChanged;
    protected virtual void OnPropertyChanged([CallerMemberName] string propertyName = null)
    {
        PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
    }
}

DContext

public partial class Context : DbContext
{
    public Context()
    {
    }

    public Context(DbContextOptions<Context> options)
        : base(options)
    {
    }

    public virtual DbSet<Products> Products { get; set; }

    protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder)
        => optionsBuilder.UseSqlServer(
            """
            Data Source=(localdb)\MSSQLLocalDB;
            Initial Catalog=Demo;
            Integrated Security=True
            """);

    protected override void OnModelCreating(ModelBuilder modelBuilder)
    {
        modelBuilder.Entity<Products>(entity =>
        {
            entity.Property(e => e.CurrentQuantity).HasColumnType("decimal(10, 2)");
        });

        OnModelCreatingPartial(modelBuilder);
    }

    partial void OnModelCreatingPartial(ModelBuilder modelBuilder);
}

Form code

public partial class Form1 : Form
{
    private Context _context = new();
    private BindingSource _bindingSource = new();
    private SortableBindingList<Products> _bindingList;
    public Form1()
    {
        InitializeComponent();
        
        _bindingList = new SortableBindingList<Products>(
            _context.Products.OrderBy(p => p.ProductName).ToList());

        _bindingSource.DataSource = _bindingList;
        dataGridView1.DataSource = _bindingSource;
        dataGridView1.Columns["Id"]!.ReadOnly = true;
        dataGridView1.ExpandColumns();
        dataGridView1.Spread();
    }

    private void SaveButton_Click(object sender, EventArgs e)
    {
        var affected = _context.SaveChanges();
        MessageBox.Show(affected == 0 ? "Nothing saved" : "Saved");
    }
}

Another option if this is only for simple updates is to look at a TableAdapter which is easy for what is being asked but getting into more advance coding without understanding TableAdapters can become frustrating. Best to use EF Core.

Below is the database which i have created in sql server .

No, its' not, it's a screenshot and I can't query screenshots.

Please post table design and some some sample data as SQL script and the expected result.