I have a combobox on a windows form that I fill with a list of names. At the moment I have the following code inside the Form class and it works fine
// This section opens a connection to the database, selects all the portfolio names that have an "in Use" value of 1, and then
// fills Combo Box 2 with the values.
SqlConnection myConnection = new SqlConnection(#"Data Source = (LocalDB)\MSSQLLocalDB; AttachDbFilename = ""C:\Users\Nick\Documents\Investments 4.mdf""; Integrated Security = True; Connect Timeout = 30");
myConnection.Open();
SqlCommand myCommand2 = new SqlCommand();
myCommand2.Connection = myConnection;
myCommand2.CommandText = "SELECT Portfolio_Name FROM Dbo.Name WHERE In_use = 1";
SqlDataReader myReader2 = myCommand2.ExecuteReader();
while (myReader2.Read())
{
comboBox2.Items.Add(myReader2[0]);
}
myConnection.Close();
I would like to be able to extract this into a separate method, and put it into a separate class for general utility methods. However, I'm stuck on a really simple issue. When I put the code into a class, I need to be able to tell it which combox box I want to fill, and I can't figure out how to pass in that information. Sorry if the answer is obvious, but any help would be gratefully received.
Thanks!
Well, if you want to extract, then extract:
// Let's extract a class: it should provide us standard cursors,
// e.g. Protfolio Names
public static class MyData {
// Let's enumerate items returned
public static IEnumerable<string> PortfolioNames() {
// Wrap IDisposable into using
//TODO: move Connection String into a separated method/property
using (SqlConnection con = new SqlConnection(/*connection string here*/)) {
con.Open();
// Make sql readable
//DONE: when presenting something to user, sort it (order by) esp. strings
string sql =
#" select Portfolio_Name
from Dbo.Name
where In_use = 1
order by Portfolio_Name";
// Wrap IDisposable into using
using (SqlCommand q = new SqlCommand(sql, con)) {
// Wrap IDisposable into using
using (var reader = q.ExecuteReader()) {
while (reader.Read())
yield return Convert.ToString(reader[0]);
}
}
}
}
}
And then use
// Adding items in one after one manner is often a bad idea:
// it makes UI repaint each time you add an item and cause blinking.
// Let's fill the ComboBox in one go via AddRange
comboBox2.Items.AddRange(MyData.PortfolioNames().ToArray());
You can use a helper class names Portfolio for data access. The method GetNames does not require a ComboBox instance. This increases the chance that you can reuse the method in another context.
public static class Portfolio
{
public static IList<string> GetNames()
{
SqlConnection myConnection = new SqlConnection(#"Data Source = (LocalDB)\MSSQLLocalDB; AttachDbFilename = ""C:\Users\Nick\Documents\Investments 4.mdf""; Integrated Security = True; Connect Timeout = 30");
myConnection.Open();
SqlCommand myCommand2 = new SqlCommand();
myCommand2.Connection = myConnection;
myCommand2.CommandText = "SELECT Portfolio_Name FROM Dbo.Name WHERE In_use = 1";
SqlDataReader myReader2 = myCommand2.ExecuteReader();
var portfolioNames = new List<string>();
while (myReader2.Read())
{
portfolioNames.Add(myReader2[0]);
}
myConnection.Close();
return portfolioNames;
}
}
Then in your Form you can do something like this:
var names = Portfolio.GetNames();
foreach (var name in names)
{
combobox2.Items.Add(name);
}
It is so simple:
public class MyUtility
{
public static void FillComboBox(System.Windows.Forms.ComboBox comboBox)
{
//comboBox.Items.Clear(); //enable this line if required
using (SqlConnection myConnection = new SqlConnection(#"Data Source = (LocalDB)\MSSQLLocalDB; AttachDbFilename = ""C:\Users\Nick\Documents\Investments 4.mdf""; Integrated Security = True; Connect Timeout = 30"))
{
myConnection.Open();
using (SqlCommand myCommand2 = new SqlCommand())
{
myCommand2.Connection = myConnection;
myCommand2.CommandText = "SELECT Portfolio_Name FROM Dbo.Name WHERE In_use = 1";
using (SqlDataReader myReader2 = myCommand2.ExecuteReader())
{
while (myReader2.Read())
{
comboBox.Items.Add(myReader2[0]);
}
}
}
//myConnection.Close(); //not required inside using block
}
}
}
you may use other methods to get connection string (e.g. from config file).
The usage is so simple, no extra code required:
MyUtility.FillComboBox(comboBox2);
Related
Trying to set up a connection to my local SQL Server Express instance so that I can display columns in a listbox. Th build runs fine and I can't see errors, but there is no data in the listbox. I have tested the query and that is fine. I am using NT Authentication to the database. Any ideas where I might have gone wrong?
public partial class Form1 : Form
{
public Form1()
{
InitializeComponent();
}
private void customers_SelectedIndexChanged(object sender, EventArgs e)
{
string commstring = "Driver ={SQL Server}; Server = DESKTOP-5T4MHHR\\SQLEXPRESS; Database = AdventureWorks2014; Trusted_Connection = Yes;";
string connstring = "SELECT FirstName, LastName FROM Person.Person";
SqlDataAdapter customerDataAdapater = new SqlDataAdapter(commstring, connstring);
DataSet customerDataSet = new DataSet();
customerDataAdapater.Fill(customerDataSet, "Person.Person");
DataTable customerDataTable = new DataTable();
customerDataTable = customerDataSet.Tables[0];
foreach (DataRow dataRow in customerDataTable.Rows)
{
customers.Items.Add(dataRow["FirstName"] + " (" + dataRow["LastName"] + ")");
}
}
}
I tested your code in a sample project here and I realized you passed the parameters to SqlDataAdapter constructor in a wrong order.
After changing the follow line:
SqlDataAdapter customerDataAdapater = new SqlDataAdapter(commstring, connstring);
by
SqlDataAdapter customerDataAdapater = new SqlDataAdapter(connstring, commstring);
the listbox was filled successfully.
Your connection string seems weird.....
Could you try using just this:
string commstring = "Server=DESKTOP-5T4MHHR\\SQLEXPRESS;Database=AdventureWorks2014;Trusted_Connection=Yes;";
Also: why are you first creating a DataSet, filling in a single set of data, and then extracting a DataTable from it?? This is unnecessarily complicated code - just use this instead:
SqlDataAdapter customerDataAdapater = new SqlDataAdapter(commstring, connstring);
// if you only ever need *one* set of data - just use a DataTable directly!
DataTable customerDataTable = new DataTable();
// Fill DataTable with the data from the query
customerDataAdapater.Fill(customerDataTable);
Update: I would really rewrite your code to something like this:
// create a separate class - call it whatever you like
public class DataProvider
{
// define a method to provide that data to you
public List<string> GetPeople()
{
// define connection string (I'd really load that from CONFIG, in real world)
string connstring = "Server=MSEDTOP;Database=AdventureWorks2014;Trusted_Connection=Yes;";
// define your query
string query = "SELECT FirstName, LastName FROM Person.Person";
// prepare a variable to hold the results
List<string> entries = new List<string>();
// put your SqlConnection and SqlCommand into "using" blocks
using (SqlConnection conn = new SqlConnection(connstring))
using (SqlCommand cmd = new SqlCommand(query, conn))
{
conn.Open();
// iterate over the results using a SqlDataReader
using (SqlDataReader rdr = cmd.ExecuteReader())
{
while (rdr.Read())
{
// get first and last name from current row of query
string firstName = rdr.GetFieldValue<string>(0);
string lastName = rdr.GetFieldValue<string>(1);
// add entry to result list
entries.Add(firstName + " " + lastName);
}
rdr.Close();
}
conn.Close();
}
// return the results
return entries;
}
}
And in your code-behind, you only need to do something like this:
protected override void OnLoad(.....)
{
if (!IsPostback)
{
List<string> people = new DataProvider().GetPeople();
customers.DataSource = people;
customers.DataBind();
}
}
but I still don't understand what you were trying to when the SelectedIndexChanged event happens.....
I have set up a listbox called lboxsupplier, i have also created a data adapter which i then used to populate the supplier listbox. When i run the form the listbox is empty. I want the listbox to populate with supplier ID and company which i will then click on to populate another listbox with products.
Namespace Pennyburn_Greg
{
public partial class FormProcess : Form
{
SqlDataAdapter daSupplier;
DataSet dsPennyburnGreg = new DataSet();
SqlConnection conn;
SqlCommand cmdSupplierDetails;
SqlCommandBuilder cmdBSupplier;
DataRow drSupplier;
String connstr, sqlSupplier;
public FormProcess()
{
InitializeComponent();
}
private void FormProcess_Load(object sender, EventArgs e)
{
connstr = #"Data Source= arlene-pc; Initial Catalog= PennyburnGreg; Integrated Security=True";
//dataAdapter for supplier listbox
sqlSupplier = #"Select* from Supplier";
conn = new SqlConnection(connstr);
cmdSupplierDetails = new SqlCommand(sqlSupplier, conn);
daSupplier = new SqlDataAdapter(cmdSupplierDetails);
daSupplier.FillSchema(dsPennyburnGreg, SchemaType.Source, "Supplier");
}
private void filllboxsupplier(string str)
{
daSupplier.Fill(dsPennyburnGreg, "Supplier");
lboxsupplier.DataSource = dsPennyburnGreg.Tables["Supplier"];
lboxsupplier.DisplayMember = "Company";
lboxsupplier.ValueMember = "SupplierID";
}
}
}
First of all, why are you calling FillSchema, rather should be calling Fill method to get the data, like
daSupplier.Fill(dsPennyburnGreg, "Supplier");
Once you have the dataset filled, then in your FormProcess_Load() you can add the dataset as datasource to the listbox like
lboxsupplier.DataSource = dsPennyburnGreg.Tables["Supplier"]
First thing you need to do is loosely couple your UI and data a little bit. Try this code:
// Returns a DataTable of ALL suppliers
private DataTable GetSuppliers()
{
return GetSuppliers(0);
}
// Returns a DataTable of the given supplier
private DataTable GetSuppliers(int supplierId)
{
using (var connection = new SqlCommand())
{
connection.ConnectionString = #"Data Source= arlene-pc; Initial Catalog= PennyburnGreg; Integrated Security=True";
using (var command = new SqlCommand())
{
connection.Open();
command.CommandType = CommandType.Text;
command.Connection = connection;
if (supplierId == 0)
{
command.commandText = "SELECT * FROM Supplier";
}
else
{
command.commandText = "SELECT * FROM Supplier WHERE SupplierId=#id";
command.Parameters.AddWithValue("#id", supplierId);
}
using (var adapter = new SqlDataAdapter())
{
using (var ds = new DataSet())
{
adapter.SelectCommand = command;
adapter.Fill(ds);
if (ds.Tables.Count > 0)
return ds.Tables[0];
}
}
}
}
return null;
}
And now you can just do this:
lboxsupplier.DataSource = GetSuppliers(int.Parse(lboxsupplier.SelectedValue));
lboxsupplier.DisplayMember = "Company";
lboxsupplier.ValueMember = "SupplierID";
Or if you need all Suppliers, just do this:
lboxsupplier.DataSource = GetSuppliers();
lboxsupplier.DisplayMember = "Company";
lboxsupplier.ValueMember = "SupplierID";
This code will provide some separation. This is still not ideal, but beats what you had.
You're not doing anything with the listbox control in FormProcess_Load, so it will be empty when it first loads. I'm assuming you have lboxsupplier_Click bound to the Click event of lboxsupplier? If so, then you'll need to click on that listbox before it will populate the Dataset (which is a very odd user experience, but if that's truly what you need...). If lboxsupplier_Click isn't an event handler, then you're going to have to manually call it.
If it still isn't populating, then try running your query against the database directly, and make sure that it returns data and has columns named "Company" and "SupplierID"
Im trying to build up a little status-tool. I need to get results of multiple queries (about 4-5). The general connection-setup and 'how-to-read-data' is already done but I cant figure out how the another query executed.
Everything I found while searching for it is for the SqlClient. Im totally overcharged with this.
Here is my code so far (be patient, im a newbie to this):
private void button1_Click(object sender, EventArgs e)
{
if(listView1.Items.Count > 1)
{
listView1.Items.Clear();
}
var listMember = new List<string>{};
var listOnline = new List<string>{};
// SQL PART //
string connString = "Server=10*****;Port=3306;Database=e***;Uid=e***;password=********************;";
MySqlConnection conn = new MySqlConnection(connString);
MySqlCommand command = conn.CreateCommand();
command.CommandText = "SELECT fullname,online FROM member WHERE active = '1' ORDER BY online DESC";
try
{
conn.Open();
}
catch (Exception ex)
{
listView1.Items.Add("Error: " + ex);
}
MySqlDataReader reader = command.ExecuteReader();
while(reader.Read())
{
listMember.Add(reader["fullname"].ToString());
listOnline.Add(reader["online"].ToString());
}
conn.Close();
// SQL ENDING //
// SET ENTRIES TO LISTVIEW //
int counter = 0;
foreach(string member in listMember)
{
ListViewItem item = new ListViewItem(new[] { member, listOnline.ElementAt(counter) });
item.ForeColor = Color.Green;
listView1.Items.Add(item);
counter++;
}
}
Im not really sure how the design/layout will look like in the end, so I would like to just append the results to lists in the sql-part to process the data later out of the lists.
Do I really have to setup a complete new connection after conn.Close()? Or is there any other way? I can just imagine: 5 queries with their own connection,try,catch and 2 loops... this will get about 100-200 lines just for getting the results out of 5 queries. Isnt that a bit too much for such an easy thing?
Hope for some help.
Greetings.
According to the new comments my latest code:
Top:
public partial class Form1 : Form
{
public static string connString = "Server=10****;Port=3306;Database=e****;Uid=e****;password=****;";
public Form1()
{
InitializeComponent();
MySqlConnection conn = new MySqlConnection(connString); // Error gone!
}
Body part:
public void QueryTwoFields(string s, List<string> S1, List<string> S2)
{
try
{
MySqlCommand cmd = conn.CreateCommand(); // ERROR: conn does not exist in the current context.
cmd.CommandType = CommandType.Text;
string command = s;
cmd.CommandText = command;
MySqlDataReader sqlreader = cmd.ExecuteReader();
while (sqlreader.Read())
{
S1.Add(sqlreader[0].ToString());
S2.Add(sqlreader[1].ToString());
}
sqlreader.Close();
}
catch (Exception ex)
{
MessageBox.Show(ex.ToString());
}
}
private void button1_Click(object sender, EventArgs e)
{
if(listView1.Items.Count > 1)
{
listView1.Items.Clear();
}
var listMember = new List<string>{};
var listOnline = new List<string>{};
using (conn) // ERROR: conn does not exist in the current context.
{
conn.Open();
///...1st Query
QueryTwoFields("SELECT fullname,online FROM member WHERE active = '1' ORDER BY online DESC",listMember,listOnline);
//...2nd query
//QueryTwoFields("your new Select Statement", otherList, otherList);
}
}
You don't have to close connection every time you execute one query rarher than close the sqlreader assigned to that connection. Finally when all of your queries have been executed you close the connection. Consider also the use of using:
You cal also define a method for execution your Query in order for your code not to be repetive:
public void QueryTwoFields(string s, List<string> S1, List<string> S2)
///Select into List S1 and List S2 from Database (2 fields)
{
try
{
MySqlCommand cmd = conn.CreateCommand();
cmd.CommandType = CommandType.Text;
string command = s;
cmd.CommandText = command;
MySqlDataReader sqlreader = cmd.ExecuteReader();
while (sqlreader.Read())
{
S1.Add(sqlreader[0].ToString());
S2.Add(sqlreader[1].ToString());
}
sqlreader.Close();
}
catch (Exception ex)
{
MessageBox.Show(ex.ToString());
}
}
private void button1_Click(object sender, EventArgs e)
{
if(listView1.Items.Count > 1)
{
listView1.Items.Clear();
}
var listMember = new List<string>{};
var listOnline = new List<string>{};
// SQL PART //
using (conn)
{
conn.Open();
///...1st Query
QueryTwoFields("SELECT fullname,online FROM member WHERE active = '1' ORDER BY online DESC",listmember,listonline)
//...2nd query
QueryTwoFields("your new Select Statement",myOtherList1,myOtherlist2)
....
}
}
EDIT :
Take in mind you cant define QueryTwoFields method inside button handler. You must define it outside (see code above).
Also Define your connection data in the start of the programm:
namespace MyProject
{
/// <summary>
/// Defiine your connectionstring and connection
/// </summary>
///
public partial class Form1 : Form
{ public static string connString = "Server=10*****;Port=3306;Database=e***;Uid=e***;password=********************;";
MySqlConnection conn = new MySqlConnection(connString);
.........
Datatables are fantastic
Using a data table is a nice way to do both read and write. And it comes with the luxury of eveything you can do with a datatable - like asssigning it directly to a datagrid control, sorting, selecting and deleting while disconnected.
The sample below assumes a MySqlConnection conection property managed by calls to your own OpenConnection() and CloseConnection() methods not shown.
Simple datatable read demo:
public DataTable Select(string query = "")
{
//Typical sql: "SELECT * FROM motorparameter"
DataTable dt = new DataTable();
//Open connection
if (this.OpenConnection() == true)
{
//Create Command
MySqlCommand cmd = new MySqlCommand(query, connection);
//Create a data reader and Execute the command
MySqlDataReader dataReader = cmd.ExecuteReader();
dt.Load(dataReader);
//close Data Reader
dataReader.Close();
//close Connection
this.CloseConnection();
//return data table
return dt;
}
else
{
return dt;
}
}
In case of writing back the datatable to the database - supply the SQL you used in the read (or would have used to read to the data table):
public void Save(DataTable dt, string DataTableSqlSelect)
{
//Typically "SELECT * FROM motorparameter"
string query = DataTableSqlSelect;
//Open connection
if (this.OpenConnection() == true)
{
//Create Command
MySqlCommand mySqlCmd = new MySqlCommand(query, connection);
MySqlDataAdapter adapter = new MySqlDataAdapter(mySqlCmd);
MySqlCommandBuilder myCB = new MySqlCommandBuilder(adapter);
adapter.UpdateCommand = myCB.GetUpdateCommand();
adapter.Update(dt);
//close Connection
this.CloseConnection();
}
else
{
}
}
The neat thing the datatable is extremely flexible. You can run your own selects against the table once it contains data and before writing back you can set or reset what rows needs updating and by default the datatable keeps track of what rows you update in the table. Do not forget primary key column(s) for all tables in the db.
For multiple queries consider if possible using a join between the database tables or same table if data related or use a UNION sql syntax if column count and type of data is the same. You can allways "create" your extra column in the select to differ what data comes from what part of the UNION.
Also consider using CASE WHEN sql syntax to conditionally select data from different sources.
I created a sale table which Insert function does not work properly. It shows the error message like this "ExecuteNonQuery requires an open and available Connection. The connection's current state is closed." If I removed Sql Close Statement on Line 14, it shows this error msg "There is already an open DataReader associated with this Command which must be closed first." My code below work like this. I checked available stocks from my Product table. If quantity order is greater than quantity from Product Table, show error message. Otherwise, proceed to inserting order information into Sale Table. Any help is appreciated.
private void btnOrder_Click(object sender, EventArgs e)
{
int iQuantityDB;
int iCustomerID = Convert.ToInt32(txtCustomerID.Text);
int iProductID = Convert.ToInt32(txtProductID.Text);
decimal dPrice = Convert.ToDecimal(txtPrice.Text);
int iQuantity = Convert.ToInt32(txtQuantity.Text);
decimal dSubtotal = Convert.ToDecimal(txtSubTotal.Text);
decimal dGST = Convert.ToDecimal(txtGST.Text);
decimal dTotal = Convert.ToDecimal(txtTotal.Text);
string strConnectionString = #"Data Source = KK\SQLEXPRESS; Integrated Security = SSPI; Initial Catalog = JeanDB; MultipleActiveResultSets=True;";
using (var sqlconn = new SqlConnection(strConnectionString))
{
sqlconn.Open();
string querySelectQuantity = #"Select Quantity from dbo.JeanProduct WHERE ProductID = #iProductID";
using (var cmdOrder = new SqlCommand(querySelectQuantity, sqlconn))
{
using (var sdRead = cmdOrder.ExecuteReader())
{
sdRead.Read();
iQuantityDB = Convert.ToInt32(sdRead["Quantity"]);
}
}
if (iQuantityDB > iQuantity)
{
string InsertQuery = #"INSERT INTO Sale(CustomerID, ProductID, Price, Quantity, Subtotal, GST, Total)VALUES(#iCustomerID, #iProductID, #dPrice, #iQuantity, #dSubtotal, #dGST, #Total)";
using (var InsertCMD = new SqlCommand(InsertQuery, sqlconn))
{
InsertCMD.Connection = sqlconn;
InsertCMD.Parameters.AddWithValue("#iCustomerID", iCustomerID);
InsertCMD.Parameters.AddWithValue("#iProdcutID", iProductID);
InsertCMD.Parameters.AddWithValue("#dPrice", dPrice);
InsertCMD.Parameters.AddWithValue("#iQuantity", iQuantity);
InsertCMD.Parameters.AddWithValue("#dSubtotal", dSubtotal);
InsertCMD.Parameters.AddWithValue("#dGST", dGST);
InsertCMD.Parameters.AddWithValue("#dTotal", dTotal);
InsertCMD.ExecuteNonQuery();
LoadDataonTable();
}
}
else
{
MessageBox.Show("no more stock");
}
sqlconn.Close();
}
}
You should change your connection string to
string strConnectionString = #"Data Source = KK\SQLEXPRESS;
Integrated Security = SSPI;
Initial Catalog = JeanDB;
MultipleActiveResultSets=True";
And do not close the connection between the Reader.Read and the ExecuteNonQuery.
You need at least Sql Server 2005 for this to work.
The connection used by a SqlDataReader cannot be used for other operations unless you set the connection string with the MultipleActiveResultSets key. Of course you could open two connection objects (with the same connection string) and use one for the SqlDataReader and one to Execute your command.
Not really linked to your problem, but I suggest to use a parameterized query also for the SELECT part of your code.
Moreover, you should use the Using Statement around the disposable object to ensure the proper closing and disposing also in case of exceptions. Finally, the syntax used in the INSERT INTO is not correct. I think that this code could explain some of the points explained above.
string strConnectionString = #"......;MultipleActiveResultSets=True;";
using(SqlConnection sqlconn = new SqlConnection(strConnectionString))
{
sqlconn.Open();
string querySelectQuantity = #"Select Quantity from dbo.JeanProduct
WHERE ProductID = #id";
using(SqlCommand cmdOrder = new SqlCommand(querySelectQuantity, sqlconn))
{
cmdOrder.AddWithValue("#id", Convert.ToInt32(txtProductID.Text));
using(SqlDataReader sdRead = cmdOrder.ExecuteReader())
{
if(sdRead.Read())
{
.....
string InsertQuery = #"INSERT INTO Sale(SaleID, CustomerID, ProductID,
Price, Quantity, Subtotal, GST, Total)VALUES(#iCustomerID,
#iProductID, #dPrice, #iQuantity,
#dSubtotal, #dGST, #Total)";
using(SqlCommand InsertCMD = new SqlCommand(InsertQuery, sqlconn))
{
InsertCMD.Parameters.AddWithValue("#iCustomerID", iCustomerID);
....
InsertCMD.ExecuteNonQuery();
LoadDataonTable();
}
}
else
{
MessageBox.Show("no more stock");
}
}
}
}
You've closed your SqlConnection after the reader execution / read cycle (and in the other error, you've kept the reader open while trying to execute another command).
Either close the reader and leave the connection open for the insert, or open a new connection for the insert.
Better still, use using to handle the disposal of the resources for you, and scope the DB resources to be released as soon as you are done with them, e.g.:
using (var sqlconn = new SqlConnection(strConnectionString))
{
sqlconn.Open();
string querySelectQuantity = "Select Quantity ...";
using var (cmdOrder = new SqlCommand(querySelectQuantity, sqlconn))
{
int iQuantityDB;
using (var sdRead = cmdOrder.ExecuteReader())
{
sdRead.Read();
iQuantityDB = Convert.ToInt32(sdRead["Quantity"]);
} // Dispose reader
// sqlconn.Close(); <-- Don't close
} // cmdOrder disposed here
if (iQuantityDB > iQuantity)
{
string InsertQuery = "INSERT INTO ...";
using var (InsertCMD = new SqlCommand(InsertQuery, sqlconn))
{
// ...
} // InsertCmd disposed here
}
} // Sql Connection disposed here
This will overcome many bugs, such as the one you've got where you are conditionally closing the command + connection in an if branch.
[Using: C# 3.5 + SQL Server 2005]
I have some code in the Business Layer that wraps in a TransactionScope the creation of an order and its details:
DAL.DAL_OrdenDeCompra dalOrdenDeCompra = new GOA.DAL.DAL_OrdenDeCompra();
DAL.DAL_ItemDeUnaOrden dalItemDeUnaOrden = new GOA.DAL.DAL_ItemDeUnaOrden();
using (TransactionScope transaccion = new TransactionScope())
{
//Insertion of the order
orden.Id = dalOrdenDeCompra.InsertarOrdenDeCompra(orden.NumeroOrden, orden.PuntoDeEntregaParaLaOrden.Id, (int)orden.TipoDeCompra, orden.FechaOrden, orden.Observaciones);
foreach (ItemDeUnaOrden item in orden.Items)
{
//Insertion of each one of its items.
dalItemDeUnaOrden.InsertarItemDeUnaOrden(orden.Id, item.CodigoProductoAudifarma, item.CodigoProductoJanssen, item.CodigoEAN13, item.Descripcion, item.CantidadOriginal, item.ValorUnitario);
}
transaccion.Complete();
}
return true;
And here is the DAL code that perform the inserts:
public int InsertarOrdenDeCompra(string pNumeroOrden, int pPuntoEntregaId, int pTipoDeCompra, DateTime pFechaOrden, string pObservaciones)
{
try
{
DataTable dataTable = new DataTable();
using (SqlConnection conexion = new SqlConnection())
{
using (SqlCommand comando = new SqlCommand())
{
ConnectionStringSettings conString = ConfigurationManager.ConnectionStrings["CSMARTDB"];
conexion.ConnectionString = conString.ConnectionString;
conexion.Open();
comando.Connection = conexion;
comando.CommandType = CommandType.StoredProcedure;
comando.CommandText = "GOA_InsertarOrdenDeCompra";
//...parameters setting
return (int)comando.ExecuteScalar();
...
public int InsertarItemDeUnaOrden(int pOrdenDeCompraId, string pCodigoProductoAudifarma, string pCodigoProductoJanssen, string pCodigoEAN13, string pDescripcion, int pCantidadOriginal, decimal pValorUnitario)
{
try
{
DataTable dataTable = new DataTable();
using (SqlConnection conexion = new SqlConnection())
{
using (SqlCommand comando = new SqlCommand())
{
ConnectionStringSettings conString = ConfigurationManager.ConnectionStrings["CSMARTDB"];
conexion.ConnectionString = conString.ConnectionString;
conexion.Open();
comando.Connection = conexion;
comando.CommandType = CommandType.StoredProcedure;
comando.CommandText = "GOA_InsertarItemDeUnaOrden";
//... parameters setting
return comando.ExecuteNonQuery();
Now, my problem is in the items insertion; when the InsertarItemDeUnaOrden tries to open a new connection an exception is rised because that would cause the TransactionScope to try promoting to MSDTC, wich I don't have enabled and I would prefer not to enable.
My doubts:
Understandig that the method tht starts the transaction is in the business layer and I don't want there any SqlConnection, ¿can I use another design for my data access so I'm able to reuse the same connection?
Should I enable MSDTC and forget about it?
Thanks.
EDIT: solution
I created a new class in the DAL to hold transactions like this:
namespace GOA.DAL
{
public class DAL_Management
{
public SqlConnection ConexionTransaccional { get; set; }
public bool TransaccionAbierta { get; set; }
public DAL_Management(bool pIniciarTransaccion)
{
if (pIniciarTransaccion)
{
this.IniciarTransaccion();
}
else
{
TransaccionAbierta = false;
}
}
private void IniciarTransaccion()
{
this.TransaccionAbierta = true;
this.ConexionTransaccional = new SqlConnection();
ConnectionStringSettings conString = ConfigurationManager.ConnectionStrings["CSMARTDB"];
this.ConexionTransaccional.ConnectionString = conString.ConnectionString;
this.ConexionTransaccional.Open();
}
public void FinalizarTransaccion()
{
this.ConexionTransaccional.Close();
this.ConexionTransaccional = null;
this.TransaccionAbierta = false;
}
}
}
I modified the DAL execution methods to receive a parameter of that new class, and use it like this:
public int InsertarItemDeUnaOrden(int pOrdenDeCompraId, string pCodigoProductoAudifarma, string pCodigoProductoJanssen, string pCodigoEAN13, string pDescripcion, int pCantidadOriginal, decimal pValorUnitario, DAL_Management pManejadorDAL)
{
try
{
DataTable dataTable = new DataTable();
using (SqlConnection conexion = new SqlConnection())
{
using (SqlCommand comando = new SqlCommand())
{
if (pManejadorDAL.TransaccionAbierta == true)
{
comando.Connection = pManejadorDAL.ConexionTransaccional;
}
else
{
ConnectionStringSettings conString = ConfigurationManager.ConnectionStrings["CSMARTDB"];
conexion.ConnectionString = conString.ConnectionString;
conexion.Open();
comando.Connection = conexion;
}
comando.CommandType = CommandType.StoredProcedure;
comando.CommandText = "GOA_InsertarItemDeUnaOrden";
And finally, modified the calling class:
DAL.DAL_OrdenDeCompra dalOrdenDeCompra = new GOA.DAL.DAL_OrdenDeCompra();
DAL.DAL_ItemDeUnaOrden dalItemDeUnaOrden = new GOA.DAL.DAL_ItemDeUnaOrden();
using (TransactionScope transaccion = new TransactionScope())
{
DAL.DAL_Management dalManagement = new GOA.DAL.DAL_Management(true);
orden.Id = dalOrdenDeCompra.InsertarOrdenDeCompra(orden.NumeroOrden, orden.PuntoDeEntregaParaLaOrden.Id, (int)orden.TipoDeCompra, orden.FechaOrden, orden.Observaciones, dalManagement);
foreach (ItemDeUnaOrden item in orden.Items)
{
dalItemDeUnaOrden.InsertarItemDeUnaOrden(orden.Id, item.CodigoProductoAudifarma, item.CodigoProductoJanssen, item.CodigoEAN13, item.Descripcion, item.CantidadOriginal, item.ValorUnitario, dalManagement);
}
transaccion.Complete();
}
dalManagement.FinalizarTransaccion();
With this changes I'm inserting orders and items without enabling MSDTC.
When using TransactionScope with multiple connections against SQL Server 2005, the transaction will always escalate to a distributed one (meaning MSDTC will be used).
This is a known issue, fixed in SQL Server 2008.
One option you have is to write a single stored procedure that does all the required operations (folding up GOA_InsertarOrdenDeCompra and all calls GOA_InsertarItemDeUnaOrden). With SQL Server 2005 this can be accomplished with an XML parameter, though SQL Server 2008 (apart from not having this issue) has table-valued parameters.
Can't you create the connection outside the methods and pass the same connection to both methods through the parameters?
That way you use the same connection avoiding the promotion.
My good solution would be to rethink the architecture of the DAL.
Something like having an central DAL, that stores an connection object, and have an reference to your DAL_OrdenDeCompra and DAL_ItemDeUnaOrden objects, and passing the reference of the DAL to this objects so they can interact with the connection stored in the DAL.
And then the DAL could have an Open and Close method with reference count, open increments, close decrements and it should only dispose the connection when it reaches zero and create a new one when incrementing to one. Also the DAL should implement the IDisposable to clean the resources of the connection. Then in your Business Layer you do something like this:
using(DAL dal = new DAL())
{
DAL.DAL_OrdenDeCompra dalOrdenDeCompra = dal.OrdenDeCompra;
DAL.DAL_ItemDeUnaOrden dalItemDeUnaOrden = dal.ItemDeUnaOrden;
using (TransactionScope transaccion = new TransactionScope())
{
dal.Open();
//Insertion of the order
orden.Id = dalOrdenDeCompra.InsertarOrdenDeCompra(orden.NumeroOrden, orden.PuntoDeEntregaParaLaOrden.Id, (int)orden.TipoDeCompra, orden.FechaOrden, orden.Observaciones);
foreach (ItemDeUnaOrden item in orden.Items)
{
//Insertion of each one of its items.
dalItemDeUnaOrden.InsertarItemDeUnaOrden(orden.Id, item.CodigoProductoAudifarma, item.CodigoProductoJanssen, item.CodigoEAN13, item.Descripcion, item.CantidadOriginal, item.ValorUnitario);
}
transaccion.Complete();
}
return true;
}
You could have a method in DAL.DAL_ItemDeUnaOrden which receives a collection of ItemDeUnaOrden instead of a single item, that way you can use a SqlTransaction (or TransactionScope) and iterate over the items within the DA method.
orden.Id = dalOrdenDeCompra.InsertarOrdenDeCompra(...);
dalItemDeUnaOrden.InsertarVariosItemsDeUnaOrden(orden.Items);
Depending on your code, you might not have access to your busiess objects (ItemDeUnaOrden) within you DAL, so you might need to pass the values some other way, maybe DTOs or a DataTable.