0

我认为这是我正在查看代码的那些时间之一，这一切似乎都很好，因为我的眼睛认为它会是。我需要用全新的眼光来查看这段代码并告诉我它没有加载到第一个数据网格视图中的方式。感谢您提供的任何帮助。

private DataSet DataSetRentals { get; set; }

public DataRelationForm()
{
   InitializeComponent();
}    

private void DataRelationForm_Load(object sender, EventArgs e)
{
   DataSet relationship = new DataSet("relationship");

   /////
   SqlConnection conn = Database.GetConnection();

   SqlDataAdapter adapter = new SqlDataAdapter("Select * From Car", conn);
   DataSet DataSetRentals = new DataSet("Relationship");

   adapter.FillSchema(DataSetRentals, SchemaType.Source, "Car");
   adapter.Fill(DataSetRentals, "Car");

   adapter.MissingSchemaAction = MissingSchemaAction.AddWithKey;
   adapter.Fill(DataSetRentals, "Car");

   DataTable Car;
   Car = DataSetRentals.Tables["Car"];

   foreach (DataRow drCurrent in Car.Rows)
   {
      Console.WriteLine("{0} {1}",
      drCurrent["au_fname"].ToString(),
      drCurrent["au_lname"].ToString());
   }

   ////////////////////////////////////
   SqlDataAdapter adapter2 = new SqlDataAdapter("Select * From CarRental", conn);

   adapter.FillSchema(DataSetRentals, SchemaType.Source, "Rentals");
   adapter.Fill(DataSetRentals, "Rentals");

   adapter.MissingSchemaAction = MissingSchemaAction.AddWithKey;
   adapter.Fill(DataSetRentals, "Rentals");

   DataTable CarRental;
   CarRental = DataSetRentals.Tables["Rentals"];

   foreach (DataRow drCurrent in CarRental.Rows)
   {
      Console.WriteLine("{0} {1}",
      drCurrent["au_fname"].ToString(),
      drCurrent["au_lname"].ToString());
   }

   /////
   SqlDataAdapter adapter3 = new SqlDataAdapter("Select * From Customer", conn);

   adapter.FillSchema(DataSetRentals, SchemaType.Source, "Customer");
   adapter.Fill(DataSetRentals, "Customer");

   adapter.MissingSchemaAction = MissingSchemaAction.AddWithKey;
   adapter.Fill(DataSetRentals, "Customer");

   DataTable Customer;
   Customer = DataSetRentals.Tables["Customer"];

   foreach (DataRow drCurrent in Customer.Rows)
   {
      Console.WriteLine("{0} {1}",
      drCurrent["au_fname"].ToString(),
      drCurrent["au_lname"].ToString());
   }

   ////////////////////////

   DataSetRentals.Tables.Add(Customer);
   DataSetRentals.Tables.Add(CarRental);
   DataSetRentals.Tables.Add(Car);

   DataRelation Step1 = new DataRelation("Customer2CarR",
   Customer.Columns["CustomerNo"], CarRental.Columns["CustomerNo"]);
   DataSetRentals.Relations.Add(Step1);

   DataRelation Step2 = new DataRelation("CarR2Car",
Car.Columns["CarID"], CarRental.Columns["CarID"]);
   DataSetRentals.Relations.Add(Step2);

   ////////////////////////
   CustomerGrid.DataSource= DataSetRentals.Tables["Customer"];
   CarRGrid.DataSource = DataSetRentals.Tables["CarRental"];
   CarGrid.DataSource = DataSetRentals.Tables["Car"];

   CustomerGrid.SelectionChanged += new EventHandler(Customer_SelectionChanged);
   CarRGrid.SelectionChanged += new EventHandler(CarR_SelectionChanged);
}

private void Customer_SelectionChanged(Object sender, EventArgs e)
{
   if (CustomerGrid.SelectedRows.Count > 0)
   {
      DataRowView selectedRow =
         (DataRowView)CustomerGrid.SelectedRows[0].DataBoundItem;
      DataSetRentals.Tables["CarRental"].DefaultView.RowFilter =
                "CustomerNo = " + selectedRow.Row["CustomerNo"].ToString();
        }

   else
   {

   }
}

private void CarR_SelectionChanged(Object sender, EventArgs e)
{
   if (CarRGrid.SelectedRows.Count > 0)
   {
      DataRowView selectedRow =
         (DataRowView)CarRGrid.SelectedRows[0].DataBoundItem;
      DataSetRentals.Tables["Car"].DefaultView.RowFilter =
         "CarID = " + selectedRow.Row["CarID"].ToString();
   }
}

这是该Database.GetConnection()方法的代码：

SqlConnectionStringBuilder stringBuilder = new SqlConnectionStringBuilder();
bool OnUni;

OnUni = (System.Environment.UserDomainName == "SOAC") ? true : false;

stringBuilder.DataSource = (OnUni) ? @"SOACSQLSERVER\SHOLESQLBSC" : "(local)";
stringBuilder.InitialCatalog = "CarRental_P117365";
stringBuilder.IntegratedSecurity = true;

return new SqlConnection(stringBuilder.ConnectionString);
4

2 回答 2

2

看起来您可能忘记调用SqlConnection.Open()以实际打开连接。我还建议将您的连接包装在 a 中并在其末尾using显式调用，这样您就不会意外地将其保持打开状态：SqlConnection.Close()

using(SqlConnection conn = Database.GetConnection())
{
    conn.Open();

    /*
        rest of code here
    */

    conn.Close();
}

有关正确打开/处理 SqlConnections 的其他一些好的信息/示例，您还可以查看这些 SO 问题：

于 2013-08-21T14:12:55.880 回答
0

您没有将数据绑定到任何数据源。

尝试这样的事情

            using(SqlConnection conn = Database.GetConnection())
            try
            {
                {
                 ------your code here up to DataTable Car-----
                  DataTable Car;
                 Car = DataSetRentals.Tables["Car"];

                 gridview.Datasource = Car;


                }
            }
            catch (SqlException sqlex )
            {
                string msg = "Fetch Error:";
                msg += sqlex.Message;
                throw new Exception(msg);
            }

无需打开或关闭 SQL 连接，因为这是使用打开它的顶部的 using 语句完成的，并且当它完成时关闭 \ 处理连接

于 2014-06-04T17:09:34.343 回答