如何為INSERT參數化SQL？

Question

我已經嘗試了下面的代碼，但是我的SQL表為空，並且沒有錯誤消息。 下面是我的代碼：

private void button1_Click(object sender, EventArgs e)
{
        string mainconn = ConfigurationManager.ConnectionStrings["Delivery_Inspection.Properties.Settings.TransitiondayConnectionString"].ConnectionString;

        SqlConnection sqlconn = new SqlConnection(mainconn);

        String query = "INSERT INTO Table1 (Busnumber, Remarks, Dt1check1) VALUES (@bn, @rm, @dt1)";

        using (SqlCommand command = new SqlCommand(query, sqlconn))
        {
            command.Parameters.AddWithValue("@bn", label1.Text.ToString());
            command.Parameters.AddWithValue("@rm", richTextBox1.Text.ToString());
            command.Parameters.AddWithValue("@dt1", this.dataGridView1[1, 0].Value);

            sqlconn.Open();
            int result = command.ExecuteNonQuery();

            // Check Error
            if (result < 0)
                Console.WriteLine("Error inserting data into Database!");
        }
}

Answer 1

嘗試移動sqlconn.Open(); 在創建command並執行之前

我建議也將其投入使用：

 private void button1_Click(object sender, EventArgs e)
    {
        var mainconn = ConfigurationManager.ConnectionStrings["Delivery_Inspection.Properties.Settings.TransitiondayConnectionString"].ConnectionString;
        using (var sqlconn = new SqlConnection(mainconn))
        {
            sqlconn.Open();
            var query = "INSERT into Table1(Busnumber,Remarks,Dt1check1)VALUES (@bn,@rm,@dt1)";
            using (var command = new SqlCommand(query, sqlconn))
            {
                command.Parameters.AddWithValue("@bn", label1.Text.ToString());
                command.Parameters.AddWithValue("@rm", richTextBox1.Text.ToString());
                command.Parameters.AddWithValue("@dt1", this.dataGridView1[1, 0].Value);
                var result = command.ExecuteNonQuery();

                // Check Error
                if (result < 0)
                    Console.WriteLine("Error inserting data into Database!");
            }
        }
    }