在Datagridview中显示数据库搜索结果

Muhammad Hannan 发表于 Dev

穆罕默德·汉南

我在Windows窗体应用程序c＃中将Visual Studio 2013与SQL Server 2012一起用于数据库。

我想在中显示查询搜索结果DataGridView：

public void customerSearch(int custID, DataGridView dataGridView)
{
        try
        {
            SqlConnection connection = new SqlConnection(@"Connection String");
            connection.Open();

            SqlCommand searchQuery = new SqlCommand("select * from [Customer] where custId = @custID", connection);
            searchQuery.Parameters.AddWithValue("@custId", custID);
            //searchQuery.ExecuteNonQuery();

            using (SqlDataReader reader = searchQuery.ExecuteReader())
            {
                while (reader.Read())
                {
                    dataGridView.DataBindings.ToString();
                }
            }
        }
        catch (SqlException Exception)
        {
            MessageBox.Show(Exception.ToString());
        }
        finally
        {
            connection.Close();
        }
    }
}

我得到NullReferenceException的connection.Close();任何帮助将不胜感激。

肖恩·兰格

当您将连接放入USING时，它将在块退出时自动关闭并处置您的连接。

public void customerSearch(int custID, DataGridView dataGridView)
        {
            using (SqlConnection connection = new SqlConnection(ConfigurationManager.ConnectionStrings["MyConnectionString"].ConnectionString))
            {
                try
                {

                    connection.Open();

                    SqlCommand searchQuery = new SqlCommand("select * from [Customer] where custId = @custID", connection);
                    searchQuery.Parameters.Add("@custId", SqlDbType.Int).Value = custID;
                    //searchQuery.ExecuteNonQuery();

                    using (SqlDataReader reader = searchQuery.ExecuteReader())
                    {
                        DataTable dt = new DataTable();
                        dt.Load(reader);
                        dataGridView.AutoGenerateColumns = true;
                        dataGridView.DataSource = dt;
                        dataGridView.Refresh();
                    }
                }
                catch (SqlException Exception)
                {
                    MessageBox.Show(Exception.ToString());
                }
            }
        }