如何从C＃中的其他形式中删除具有查询的列表项目

Question

我尝试从我的数据库中删除列表'ship'的列表项目。我使用2堂课将我的SQL查询分开(用于查询的shipdb.cs，用于我的船舶物业(。我想使用表单中的"删除"按钮在数据库中删除所选行。该按钮未删除行，单击删除按钮时未提及任何错误。

在shipdb.cs中：

public void Delete()
        {
            using (System.Data.SqlClient.SqlConnection connection = new System.Data.SqlClient.SqlConnection(connectionString))
            {
                connection.Open();
                Ship ship = new Ship();
                SqlCommand commandDelete = new SqlCommand("DELETE FROM Ship WHERE id = " + ship.Id, connection);
                commandDelete.ExecuteNonQuery();
            }
        }

在form1.cs中：

private void Button3_Click(object sender, EventArgs e)
        {   
             using (System.Data.SqlClient.SqlConnection connection = new System.Data.SqlClient.SqlConnection(connectionString))
                {

                if (dataGridViewShips.SelectedRows.Count == 1)
                {
                    Ship ship = (Ship)dataGridViewShips.SelectedRows[0].DataBoundItem;
                    db.Delete();
                    dataGridViewShips.DataSource = db.GetAll();
                }
            }
        }

我使用db.getall更新数据库

Answer 1

正如萨米(Sami(所说的，您没有告诉它需要删除的内容。

public void Delete(Ship ship)
{
    using (System.Data.SqlClient.SqlConnection connection = new System.Data.SqlClient.SqlConnection(connectionString))
    {
        connection.Open();
        SqlCommand commandDelete = new SqlCommand("DELETE FROM Ship WHERE id = " + ship.Id, connection);
        commandDelete.ExecuteNonQuery();
     }
}

private void Button3_Click(object sender, EventArgs e)
{   
    using (System.Data.SqlClient.SqlConnection connection = new System.Data.SqlClient.SqlConnection(connectionString))
    {
        if (dataGridViewShips.SelectedRows.Count == 1)
        {
            Ship ship = (Ship)dataGridViewShips.SelectedRows[0].DataBoundItem;
            db.Delete(ship);
            dataGridViewShips.DataSource = db.GetAll();
        }
    }
}