无法在Microsoft Access数据库[C＃]中插入数据

Question

I have an Access File that has 6 fields like this:

ID, Designation, Price, Group, Weight, DeliveryTime

In my code, I first created an OleDbConnection and an OleDbCommand inside my Database Class.

private OleDbConnection _connection = new OleDbConnection(parameter);
private OleDbCommand _command;

After that I execute the WriteData Method.

public void WriteData(string tableName, string designation, string price, string group, string weight, string deliveryTime)
    {
        _command.Connection = _connection;
        _command.CommandText = "INSERT INTO " + 
            tableName + " (ID, Designation, Price, Group, Weight, deliveryTime) 
            VALUES (@id, @des, @price, @group, @weight, @deliveryTime)";

        _command.Parameters.AddWithValue("@id", GetNextHighestItemNumber());
        _command.Parameters.AddWithValue("@des", designation);
        _command.Parameters.AddWithValue("@price", price);
        _command.Parameters.AddWithValue("@group", group);
        _command.Parameters.AddWithValue("@weight", weight);
        _command.Parameters.AddWithValue("@deliveryTime", deliveryTime);

        OpenConnection();
        _command.ExecuteNonQuery();
        CloseConnection();

        System.Windows.Forms.MessageBox.Show("Success");
    }

But there is no new Data inside my Database. I also tried it this way:

public void WriteData(string tableName, string designation, string price, string group, string weight, string deliveryTime)
    {
        _command.Connection = _connection;
        _command.CommandText = "INSERT INTO " + 
            tableName + " (ID, Designation, Price, Group, Weight, deliveryTime) 
            VALUES (?,?,?,?,?,?)";

        _command.Parameters.AddWithValue("ID", GetNextHighestItemNumber());
        _command.Parameters.AddWithValue("Designation", designation);
        _command.Parameters.AddWithValue("Price", price);
        _command.Parameters.AddWithValue("Group", group);
        _command.Parameters.AddWithValue("Weight", weight);
        _command.Parameters.AddWithValue("DeliveryTime", deliveryTime);

        OpenConnection();
        _command.ExecuteNonQuery();
        CloseConnection();

        System.Windows.Forms.MessageBox.Show("Success");
    }

Do I overlook something?

Thanks for your help!

Answer 1

I added a NEW OleDbCommand and applied the connection, command, and Parameters to it.

public void WriteData(string tableName, string designation, string price, string group, string weight, string deliveryTime)
{
    _command.CommandText = "INSERT INTO " + 
        tableName + " (ID, Designation, Price, Group, Weight, deliveryTime) 
        VALUES (?,?,?,?,?,?)";
    OleDbCommand addDataCommand = new OleDbCommand(_command.CommandText, _connection);     

    addDataCommand .Parameters.AddWithValue("ID", GetNextHighestItemNumber());
    addDataCommand .Parameters.AddWithValue("Designation", designation);
    addDataCommand .Parameters.AddWithValue("Price", price);
    addDataCommand .Parameters.AddWithValue("Group", group);
    addDataCommand .Parameters.AddWithValue("Weight", weight);
    addDataCommand .Parameters.AddWithValue("DeliveryTime", deliveryTime);

    OpenConnection();
    _command.ExecuteNonQuery();
    CloseConnection();

    System.Windows.Forms.MessageBox.Show("Success");
}

It seems that you have to create a new Command and execute it because it's working now.

Thanks for your help in the comments.