操作符& # 39;= = & # 39;不能应用于'方法group'和& # 39;int # 39;

我写信是为了开发一个有关某公司股票的程序。

我在int中有可变数量的库存，我试图获得所有数量并与文本框上写的结果进行比较。

我使用以下代码:

SqlConnection sqlcon = new SqlConnection("server=.;database=DB_TEST;trusted_connection=true"); - SERVER CONNECTION

SqlCommand sqlcmd = new SqlCommand("Select SUM(Quantity) from Stock where ProductID='" + cmbxProductID.SelectedValue + "'", sqlcon); - GETTING TOTAL QUANTITY FROM DATABASE - quantity in int
sqlcon.Open(); - SQL CONNECTION OPEN
textBox1.Text = sqlcmd.ExecuteScalar().ToString(); -- transfering total quantity to textbox1
int result=int.Parse(textBox1.Text); -- CONVERT CONTENT OF TEXTBOX to ınt
if (result == 0)
        {
            MessageBox.Show("Stock is not adequate");
        }
        sqlcmd.ExecuteNonQuery();
        sqlcon.Close()
        MessageBox.Show("Stock is OK");

SqlConnection sqlcon = new SqlConnection("server=.;database=DB_TEST;" + 
                                     "trusted_connection=true");
SqlCommand sqlkmt = new SqlCommand("Select SUM(QUANTITY) from Stock " + 
                                   "where ProductID='" + 
                                    cmbxProductID.SelectedValue + "'",  sqlcon);                       
sqlcon.Open();
int result= sqlkmt.ExecuteScalar();
sqlcon.Close();
if (result == int.Parse(textBox1.Text))
{
    MessageBox.Show("Stock in not adeqaute");
}