將DataGridView值插入MySql數據庫。 C＃

Question

我想從dataGridView1向MySql數據庫添加新值。 該代碼本身似乎是正確的，在Visual Studio 2012中沒有錯誤，但是在我的數據庫中沒有插入任何數據。 這是我正在使用的代碼：

private void button2_Click(object sender, EventArgs e)
{
   confirm exec = new confirm();      
}

public class confirm
{
   public void method(DataGridViewCellEventArgs f)
   {
      DataGridView dataGridView1 = new DataGridView();
      Label label1 = new Label(); // contains User ID which is used for payer_code
      Label label6 = new Label(); // contains current dayTime

      foreach (DataGridViewRow row in dataGridView1.Rows)
      {
         if ((bool)dataGridView1.Rows[f.RowIndex].Cells["paidDataGridViewTextBoxColumn"].Value == true)
         {
            try
            {
               string MyConnectionString = "Server=localhost; Database=contractsdb; Uid=root; Pwd=";
               MySqlConnection connection = new MySqlConnection(MyConnectionString);
               MySqlCommand cmd = new MySqlCommand();
               cmd = connection.CreateCommand();
               connection.Open();
               cmd.CommandText = "INSERT INTO payments(pay_name, pay_code, payer_code, pay_sum, pay_date)VALUES(@pay_name, @pay_code, @payer_code, @pay_sum, @pay_date)";
               cmd.Parameters.AddWithValue("@pay_name", dataGridView1.Rows[f.RowIndex].Cells["contractnameDataGridViewTextBoxColumn"].Value);
               cmd.Parameters.AddWithValue("@pay_code", dataGridView1.Rows[f.RowIndex].Cells["contractcodeDataGridViewTextBoxColumn"].Value);
               cmd.Parameters.AddWithValue("@payer_code", label1.Text);
               cmd.Parameters.AddWithValue("@pay_sum", dataGridView1.Rows[f.RowIndex].Cells["sumDataGridViewTextBoxColumn"].Value);
               cmd.Parameters.AddWithValue("@pay_date", label6.Text);
               cmd.ExecuteNonQuery();
               connection.Close();
            }   

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

Answer 1

我認為您對OOP有誤解。 像這樣做：

您的confirm類方法還應該具有datagridview1的引用（您正在創建一個空的datagridview因此它永遠不會進入foreach循環）

public void method(DataGridView datagridview1) //remove your first argument, you don't need it anymore
{
    //delete the line "DataGridView dataGridView1 = new DataGridView();"
    //and keep the rest of the code as it is
    foreach (DataGridViewRow row in dataGridView1.Rows)
    {
        if(row.Cells["paidDataGridViewTextBoxColumn"].Value == true) //it will check every row, and you don't need "DataGridViewCellEventArgs" argument now
        {
            try
            {
                //your code, it will be same here
            }
        }
}

用於調用方法：

（使用與您相同的button_click事件）

private void button2_Click(object sender, EventArgs e)
{
    confirm exec = new confirm();      
    exec.method(datagridview1); //pass "datagridview1" reference
}

它會把你原來的參考datagridview1到confirm類。