このコードを考えると：
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;
//Include mysql client namespace.
using MySql.Data.MySqlClient; // That one doesn't work !!!
using System.Configuration;
namespace CSharpMySqlSample
{
public partial class frmMySqlSample : Form
{
//Read connection string from application settings file
string ConnectionString = ConfigurationSettings.AppSettings["ConnectionString"];
MySqlConnection connection;
MySqlDataAdapter adapter;
DataTable DTItems;
public frmMySqlSample()
{
InitializeComponent();
}
private void frmMySqlSample_Load(object sender, EventArgs e)
{
//Initialize mysql connection
connection = new MySqlConnection(ConnectionString);
//Get all items in datatable
DTItems = GetAllItems();
//Fill grid with items
dataGridView1.DataSource = DTItems;
}
//Get all items from database into datatable
DataTable GetAllItems()
{
try
{
//prepare query to get all records from items table
string query = "select * from items";
//prepare adapter to run query
adapter = new MySqlDataAdapter(query, connection);
DataSet DS = new DataSet();
//get query results in dataset
adapter.Fill(DS);
// Set the UPDATE command and parameters.
adapter.UpdateCommand = new MySqlCommand(
"UPDATE items SET ItemName=@ItemName, Price=@Price, AvailableQuantity=@AvailableQuantity, Updated_Dt=NOW() WHERE ItemNumber=@ItemNumber;",
connection);
adapter.UpdateCommand.Parameters.Add("@ItemNumber", MySqlDbType.Int16, 4, "ItemNumber");
adapter.UpdateCommand.Parameters.Add("@ItemName", MySqlDbType.VarChar, 100, "ItemName");
adapter.UpdateCommand.Parameters.Add("@Price", MySqlDbType.Decimal, 10, "Price");
adapter.UpdateCommand.Parameters.Add("@AvailableQuantity", MySqlDbType.Int16, 11, "AvailableQuantity");
adapter.UpdateCommand.UpdatedRowSource = UpdateRowSource.None;
// Set the INSERT command and parameter.
adapter.InsertCommand = new MySqlCommand(
"INSERT INTO items VALUES (@ItemNumber,@ItemName,@Price,@AvailableQuantity,NOW());",
connection);
adapter.InsertCommand.Parameters.Add("@ItemNumber", MySqlDbType.Int16, 4, "ItemNumber");
adapter.InsertCommand.Parameters.Add("@ItemName", MySqlDbType.VarChar, 100, "ItemName");
adapter.InsertCommand.Parameters.Add("@Price", MySqlDbType.Decimal, 10, "Price");
adapter.InsertCommand.Parameters.Add("@AvailableQuantity", MySqlDbType.Int16, 11, "AvailableQuantity");
adapter.InsertCommand.UpdatedRowSource = UpdateRowSource.None;
// Set the DELETE command and parameter.
adapter.DeleteCommand = new MySqlCommand(
"DELETE FROM items "
+ "WHERE ItemNumber=@ItemNumber;", connection);
adapter.DeleteCommand.Parameters.Add("@ItemNumber",
MySqlDbType.Int16, 4, "ItemNumber");
adapter.DeleteCommand.UpdatedRowSource = UpdateRowSource.None;
//return datatable with all records
return DS.Tables[0];
}
catch (Exception ex)
{
MessageBox.Show(ex.Message);
}
return null;
}
private void btnSave_Click(object sender, EventArgs e)
{
try
{
//Save records in database using DTItems which is datasource for Grid
adapter.Update(DTItems);
//Refresh grid
DTItems = GetAllItems();
dataGridView1.DataSource = DTItems;
MessageBox.Show("Items saved successfully...");
}
catch(Exception ex)
{
MessageBox.Show(ex.Message);
}
}
private void btnDelete_Click(object sender, EventArgs e)
{
if (dataGridView1.SelectedRows.Count > 0)
{
//Delete a row from grid first.
dataGridView1.Rows.Remove(dataGridView1.SelectedRows[0]);
//Save records again. This will delete record from database.
adapter.Update(DTItems);
//Refresh grid. Get items again from database and show it in grid.
DTItems = GetAllItems();
dataGridView1.DataSource = DTItems;
MessageBox.Show("Selected item deleted successfully...");
}
else
{
MessageBox.Show("You must select entire row in order to delete it.");
}
}
}
}
コンパイル後、次のようになります。
error CS0246: The type or namespace name 'MySqlConnection' could not be found (are you missing a using directive or an assembly reference?)
しかし、私はコネクタをチェックしました:
そして、それはインストールされています..
では、何が問題なのですか?
ありがとう
