更改不会保存到SQL Server数据库

Question

代码可以正常编译，没有错误或警告，但数据库不会更改。我的意思是所做的更改不会保存到数据库中。

我编写了以下方法：

private void Test2()
    {
        connection = new SqlConnection();
        string Conn = @"Data Source=(LocalDB)\MSSQLLocalDB;"
                                    + @"AttachDbFilename=|DataDirectory|\User.mdf;"
                                    + "Integrated Security=True;"
                                    + "Connect Timeout=30";

       // string sqlString = Properties.Settings.Default.ConnectionString;
        SqlConnection sqlConnection = new SqlConnection(Conn);
        try
        {
                string SQL = "UPDATE Primuser SET Following = @Following WHERE Insta = @Insta";
                SqlCommand sqlCommand = new SqlCommand(SQL, sqlConnection);
                sqlCommand.Parameters.AddWithValue("@Following", "123");
                sqlCommand.Parameters.AddWithValue("@Insta", "hgd");
                sqlCommand.CommandText = SQL;

                sqlConnection.Open();
                sqlCommand.ExecuteNonQuery();
                sqlConnection.Close();

                MessageBox.Show("Record Updated");

        }
        catch (Exception err)
        {
            MessageBox.Show(err.Message);
        }

    }

，并且在此代码中，结果大于0。

private void Test2()
    {
        connection = new SqlConnection();
        connection.ConnectionString = @"Data Source=(LocalDB)\MSSQLLocalDB;"
                                    + @"AttachDbFilename=|DataDirectory|\User.mdf;"
                                    + "Integrated Security=True;"
                                    + "Connect Timeout=30";
        SqlCommand command = new SqlCommand();
        command.CommandText = "SELECT * FROM Primuser";
        command.Connection = connection;

        SqlDataAdapter adapter = new SqlDataAdapter();
        adapter.SelectCommand = command;
        DataSet dataset = new DataSet();
        adapter.Fill(dataset, "Primuser");

        foreach (DataRow row in dataset.Tables["Primuser"].Rows)
        {
            if (row["Insta"].ToString() == "1495")
            {
                row["Following"] = "1024";
            }
        }

        SqlCommandBuilder builder = new SqlCommandBuilder(adapter);

        try
        {
           var result = adapter.Update(dataset, "Primuser");

            if (result > 0)
                MessageBox.Show("Update Successful.");
            else
                MessageBox.Show("Update Failed.");
        }
        catch (SqlException ex)
        {
            MessageBox.Show(ex.Message);
        }
    }

，但数据库未更改。没有错误，其他查询正在运行。我可以插入，删除或选择，但是更新不起作用。