I'm trying to get all records from table and print them out in console.
My Userlist.cs
public List<Userlist> CreateList()
{
using (SqlConnection conn = new SqlConnection(Sqlstring))
{
using (SqlCommand cmd = new SqlCommand(ListCreateQuery, conn))
{
conn.Open();
using (SqlDataReader reader = cmd.ExecuteReader())
{
List<Userlist> Users = new List<Userlist>();
while (reader.Read())
{
Userlist U = new Userlist();
U.fornavn = (string)reader["Fornavn"];
U.efternavn = (string)reader["Efternavn"];
U.mail = (string)reader["Mail"];
U.tlfnr = (string)reader["TlfNr"];
Users.Add(U);
}
return Users;
}
}
}
}
And I try to print it out from my main (Or a method is fine)
if (UserAnswer == "1")
{
Console.Clear();
Userlist UL = new Userlist();
foreach (Userlist user in UL.CreateList())
{
Console.WriteLine(user);
}
Console.ReadKey();
}
When I run it, it only prints mynamespace.userlist 3 times over (my number of records)
Passing a class object into Console.WriteLine will invoke it's .ToString() method if the object is not null. If you want the property values to be displayed when calling .ToString() you can override the method in your class:
public class Userlist
{
.....
public override string ToString()
{
return "fornavn: " + fornavn + " efternavn: " + efternavn + " mail: " + mail
+ " tlfnr: " + tlfnr;
}
}
You are using toString on the object so it prints the objects name
You need to use it on each property and write:
foreach(Userlist user in UL.CreateList())
{
Console.WriteLine(user.fornavn);
Console.WriteLine(user.efternavn );
Console.WriteLine(user.mail);
Console.WriteLine(user.tlfnr);
}
Related
I'm passing two integers to a method in another class, comparing that against a database table, and creating a string for any duplicates found. I'd like to pass that string back to the calling method/class.
In calling class:
if (IsValidMfgBadgeEntries())
{
int beginningSerial = Convert.ToInt32(txtMfgBeginning.Text);
int count = Convert.ToInt32(txtMfgCount.Text);
SerialsManufacturingDB.VerifyManufacturingSerialOnly
(count, beginningSerial);
}
In separate class:
public static VerifyManufacturingSerialOnly(int count, int beginning)
{
OleDbConnection connection = BadgeDatabaseDB.GetConnection();
string checkStatement
= "SELECT OrderNumber "
+ "FROM SerialNumbers-MFG "
+ "WHERE SerialNumber = #CurrentSerial";
OleDbCommand command =
new OleDbCommand(checkStatement, connection);
string duplicateSerials = "";
for (int i = 0; i < count; i++)
{
int currentSerial = beginning;
command.Parameters.AddWithValue("#CurrentSerial", currentSerial);
try
{
connection.Open();
OleDbDataReader dataReader =
command.ExecuteReader(CommandBehavior.SingleRow);
if (dataReader.Read())
{
duplicateSerials +=
"Serial # " +
currentSerial +
" already exists in order # " +
dataReader["OrderNumber"].ToString() + "\n";
}
else
{
;
}
}
catch (OleDbException ex)
{
throw ex;
}
finally
{
connection.Close();
}
i++;
}
//WHAT TO RETURN??
}
You must declare the method with a return type (in this case string):
public static string VerifyManufacturingSerialOnly(int count, int beginning)
At the end of the method you can write
return duplicateSerials;
You can then call the method like this:
string result = SerialsManufacturingDB.VerifyManufacturingSerialOnly(count, beginningSerial);
If you have a method which is not returning a value, you must use the type placeholder void
public void DoesNotReturnAValue()
{
...
}
In fact you can use a return statement at any place in the method. A method can have several return statements. In a void method you simply write
return;
without argument.
See also
return (C# Reference)
Return with examples at dot net perls.
I faced a problem while trying to build a Windows form solution for a college assignment, and hope somebody can point out my mistake.
The solution is about a mobile shop. I have two classes, Apple and Android forms. I need to read the data in the database table, categorize the entries to either Android or Apple phones, and then display all phones in a list when the form loads.
I can successfully categorize phones, but when trying to read the entries, I always end up with the same entry twice in my list on the form, while the second entry doesn't appear at all.
I know I made a big stupid mistake while doing the connection but I can't find it!.
Here is my code:
public abstract class MobilePhone {
private Int32 phoneID;
private string operatingSystem;
private string make;
private string model;
public enum Condition { Poor, Fair, Good, Mint };
private Condition condition;
private decimal originalPrice;
private DateTime datePurchase;
private string description;
private clsDataConnection dbConnection;
//constructor
public MobilePhone(string make, string model, decimal originalPrice, DateTime datePurchase, Condition condition, string description) {
this.make = make;
this.model = model;
this.originalPrice = originalPrice;
this.datePurchase = datePurchase;
this.condition = condition;
this.description = description;
}
Not complete, but that's what is relevant:
public class ApplePhone : MobilePhone {
decimal ApproxValue;
public ApplePhone(string make, string model, decimal originalPrice, DateTime datePurchase, Condition condition, string description)
: base(make, model, originalPrice, datePurchase, condition, description) {
}
The Android class is the same but with different other functions.
class Shop {
clsDataConnection dbConnection;
const int NotAdded = -1; // invalid primary key
private string name;
private decimal ApproxValue;
private Int32 phoneID;
private string operatingSystem;
private string make;
private string model;
private MobilePhone.Condition condition;
private decimal originalPrice;
private DateTime datePurchase;
private string description;
Int32 Index;
private List<MobilePhone> phonesForSale;
//constructor
public Shop(string name) {
this.name = name;
}
MobilePhone phone;
public void SelectAll() {
dbConnection = new clsDataConnection();
dbConnection.Execute("SellectAllPhones");
}
public void FilterByOperatingSystem(string operatingSystem) {
dbConnection = new clsDataConnection();
dbConnection.AddParameter("#OperatingSystem", operatingSystem);
dbConnection.Execute("FilterByOperatingSystem");
}
public Int32 Count {
get {
//return the count of records
return dbConnection.Count;
}
}
public string DescribeCurrentPhone(int Index) {
Int32 phoneID;
string make;
string model;
MobilePhone.Condition condition;
decimal originalPrice;
DateTime datePurchase;
string description;
phoneID = Convert.ToInt32(phonesForSale[Index].PhoneID);
make = Convert.ToString(phonesForSale[Index].Make);
model = Convert.ToString(phonesForSale[Index].Model);
condition = phonesForSale[Index].GetCondition;
originalPrice = Convert.ToDecimal(phonesForSale[Index].OriginalPrice);
datePurchase = Convert.ToDateTime(phonesForSale[Index].DatePurchased);
description = Convert.ToString(phonesForSale[Index].Description);
//set up a new object of class list item
string listItemText = make + " " + "|" + " " + model + " " + "|" + " " + condition + " " + "|" + " " + "£" + Math.Round(originalPrice, 2) + " " + "|" + " " + datePurchase.ToShortDateString() + " " + "|" + " " + description;
return listItemText;
}
public List<MobilePhone> Allphones {
get {
phonesForSale = new List<MobilePhone>();
int count = Count;
Index = 0;
while (Index < count) {
phoneID = Convert.ToInt32(dbConnection.DataTable.Rows[Index]["PhoneId"]);
operatingSystem = Convert.ToString(dbConnection.DataTable.Rows[Index]["OperatingSystem"]);
make = Convert.ToString(dbConnection.DataTable.Rows[Index]["Make"]);
model = Convert.ToString(dbConnection.DataTable.Rows[Index]["Model"]);
string conditionString = Convert.ToString(dbConnection.DataTable.Rows[Index]["Condition"]);
originalPrice = Convert.ToInt32(dbConnection.DataTable.Rows[Index]["OriginalPrice"]);
datePurchase = Convert.ToDateTime(dbConnection.DataTable.Rows[Index]["DatePurchased"]);
description = Convert.ToString(dbConnection.DataTable.Rows[Index]["Description"]);
// Set Condition
if (conditionString == "Poor") {
condition = MobilePhone.Condition.Poor;
} else if (conditionString == "Fair") {
condition = MobilePhone.Condition.Fair;
} else if (conditionString == "Good") {
condition = MobilePhone.Condition.Good;
} else if (conditionString == "Mint") {
condition = MobilePhone.Condition.Mint;
}
//check Operating System
if (operatingSystem == "IOS") {
phone = new ApplePhone(make, model, originalPrice, datePurchase, condition, description);
//ApproxValue = ApplePhone.CalculateApproximateValue();
} else if (operatingSystem == "Android") {
phone = new AndroidPhone(make, model, originalPrice, datePurchase, condition, description);
//ApproxValue = AndroidPhone.CalculateApproximateValue();
}
Index++;
phonesForSale.Add(phone);
}
return phonesForSale;
}
}
And the form code is:
public partial class FormMain : Form {
public FormMain() {
InitializeComponent();
Shop shop = new Shop("");
}
private void FormMain_Load(object sender, EventArgs e) {
DisplayItems("");
}
protected int DisplayItems(string operatingSystem) {
Shop MyShop = new Shop("");
Int32 RecordCount;
Int32 Index = 0;
Int32 PID;
if (operatingSystem != "") {
MyShop.FilterByOperatingSystem(operatingSystem);
} else {
MyShop.SelectAll();
}
RecordCount = MyShop.Count;
ArrayList MyPhones = new ArrayList();
while (Index < RecordCount) {
// I Suspect this line is the problem but don't know how to fix it
PID = MyShop.Allphones[Index].PhoneID
string listItemText = MyShop.DescribeCurrentPhone(PID);
//add the new item to the list
MyPhones.Add(listItemText);
//increment the index
Index++;
}
listBox1.DataSource = MyPhones;
return RecordCount;
}
I am not used to connecting to databases, so any advice will be of help!
An example of an alternative to the DB connection you have made is below
List<MyPhone> myIPhoneList = new List<Myphone>();
List<MyPhone> myAndroidList = new List<Myphone>();
SqlConnection myDBConnection = new SqlConnection("MyConnectionString"); //DB Connection
SqlCommand dbCommand = new SqlCommand("SelectAllPhones"); //Stored Procedure
SqlDataReader recordReader = dbCommand.ExecuteReader(); //Execute
//Read records return in to phone objects
while (recordReader.Read()) {
var phoneField1 = recordReader["PhoneField1FromDatabase"];
var phoneField2 = recordReader["PhoneField2FromDatabase"];
//etc...
var myPhone = new MyPhone();
myPhone.Name = phoneField1;
//etc...
if (myPhone.OS == "iPhone")
myIPhoneList.Add(myPhone);
if (myPhone.OS = "Android")
myAndroidList.Add(myPhone);
}
Just a twist to Wheels answer really,
I'd personally put a filter on the stored-proc.
SqlCommand dbCommand = new SqlCommand("SelectAllPhones"); //Stored Procedure
becomes something like:
using (SqlConnection conn = new SqlConnection())
{
using (SqlCommand cmd = new SqlCommand("SelectAllPhones", conn))
{
cmd.Parameters.Add(new SqlParameter() { ParameterName = "#OS", SqlDbType = SqlDbType.VarChar, Direction = ParameterDirection.Input, Value = phoneOS });
cmd.CommandType = CommandType.StoredProcedure;
SqlDataReader reader = cmd.ExecuteReader();
while (reader.Read())
{
// load your data...
}
}
}
Only because there is very little point dragging both sets of phone data (android/iphone) for each class. You may as well only pull back the data you require.
Of course the Stored-Proc will need an update to cater for the parameter.
something like:
AND PhoneOS = #OS
needs appending to your SQL condition.
clsDataConnection dbConnection; is unknown to me - is this a third party library or a class you've wrote and not included?
public Int32 Count
{
get
{
//return the count of records
return dbConnection.Count;
}
}
dbConnection.Count seems very non-standard. Doesn't read as if you're trying to get the number of rows, more the number of connections - which is invalid here.
dbConnection.DataTables[0].Rows.Count; would be a better way of determining the rows using your existing code, as currently it reads as if your counting the number of database connections which isn't what your after - and would be redundant if using either mine or Wheels as you wont need to know beforehand how many rows your about to process.
I'm working on a WPF App in C# with VS 2010 SP1.
I've looked at quite a few examples on here and elsewhere around the web, and my code seems correct, but when I attempt to read rows from an Access DB into a class then into an ObservableCollection (I've also tried just a List), only one ends up in the collection. I then attempt to display a list of usernames in a ListBox, and of course only the one user in the collection appears.
I've been stuck on this for a while now. Any help would be greatly appreciated. I'm hoping it's something very trivial that I'm just overlooking.
User Class:
public class User
{
public User() { }
public int UserID { get; set; }
public string UserName { get; set; }
public string UserTitle { get; set; }
public string UserArea { get; set; }
}
Code:
// Setting up DB stuff.
string s_ConnString = "Provider=Microsoft.ACE.OLEDB.12.0;Data " +
"Source=|DataDirectory|\\CloseoutApp.accdb";
OleDbConnection AccessConn = new OleDbConnection(s_ConnString);
string s_Query = "SELECT UserID, UserName, UserTitle, UserArea FROM Users " +
"ORDER BY UserID;";
OleDbCommand AccessCmd = new OleDbCommand(s_Query, AccessConn);
OleDbDataReader rdr;
AccessConn.Open();
rdr = AccessCmd.ExecuteReader();
// Collection of Users.
ObservableCollection<User> userList = new ObservableCollection<User>();
try
{
// Read each user from DB into a User instance, then add that instance to the userList.
while(rdr.Read())
{
User newUser = new User();
newUser.UserID = rdr.GetInt32(0);
newUser.UserName = rdr.GetString(1);
newUser.UserTitle = rdr.GetString(2);
newUser.UserArea = rdr.GetString(3);
userList.Add(newUser);
}
}
catch(Exception e)
{
//Update Statusbar
}
// Close the DB connection.
rdr.Close();
AccessConn.Close();
// Add users to the ListBox.
foreach(User u in userList)
{
lb_Users.Items.Add(u.UserName);
}
I had something similar happen to me when I was handling my database connection in a similar way.
Give the below code a try:
// Setting up DB stuff.
string s_ConnString = "Provider=Microsoft.ACE.OLEDB.12.0;Data " +
"Source=|DataDirectory|\\CloseoutApp.accdb";
string s_Query = "SELECT UserID, UserName, UserTitle, UserArea FROM Users " +
"ORDER BY UserID;";
ObservableCollection<User> userList = new ObservableCollection<User>();
using (OleDbConnection AccessConn = new OleDbConnection(s_ConnString))
{
using (OleDbCommand AccessCmd = AccessConn.CreateCommand())
{
AccessCmd.CommandText = s_Query;
try
{
AccessConn.Open();
OleDbDataReader rdr = AccessCmd.ExecuteReader();
while (rdr.Read())
{
User newUser = new User();
newUser.UserID = rdr.GetInt32(0);
newUser.UserName = rdr.GetValue(1).ToString();
newUser.UserTitle = rdr.GetValue(2).ToString();
newUser.UserArea = rdr.GetValue(3).ToString();
userList.Add(newUser);
}
rdr.Close();
}
catch(Exception ex)
{
//do something with ex
}
}
}
// Add users to the ListBox.
foreach (User u in userList)
{
lb_Users.Items.Add(u.UserName);
}
I am getting data from a mySql database and I am inserting it into another system. If a column has data in an incorrect format I log this and go to next row in the datatable. It works as expected but now if I have a search function in my method that gets some additional data and this function fails I want to immediately log this and go to next row. As it is now I just log it but it still gets inserted (without the value that didn't meet the search criteria).
My code:
private void updateCustomer()
{
MySqlConnection connection = new MySqlConnection("server=myServer;database=myDatabase;uid=myID;password=myPass");
MySqlCommand command = new MySqlCommand(#"mySelectCommand", connection);
DataTable customerTbl = new DataTable();
MySqlDataReader reader;
try
{
connection.Open();
reader = command.ExecuteReader();
if (reader.HasRows)
{
customerTbl.Load(reader);
}
reader.Close();
}
catch (Exception ex)
{
_out.error("Could not connect to mySql database");
}
finally
{
connection.Close();
}
foreach (DataRow row in customerTbl.Rows)
{
// Declare the customer variables
string customerID = Encoding.ASCII.GetString((byte[])row["Customer ID"]);
string ChildOf = row["Child of"].ToString();
// Create the customer object
Customer customer = new Customer();
customer.entityId = customerID;
if (ChildOf != "")
{
RecordRef parentRef = new RecordRef();
try
{
parentRef.internalId = searchCustomer(ChildOf);
}
catch
{
// If it fails here I want to log the customerID and then go to the next row in the datatable (could not find the internalid for ChildOf
_out.error(customerID + " was not updated. Error: invalid format Parent string");
}
finally
{
parentRef.typeSpecified = false;
customer.parent = parentRef;
}
}
// Invoke update() operation
WriteResponse response = _service.update(customer);
// Process the response
if (response.status.isSuccess)
{
}
else
{
_out.error(customerID + " was not updated. Error: " + getStatusDetails(response.status));
}
}
}
You need to remove the row in the catch block, and change the foreach loop to a backwards for loop to handle the removals.
I realized that I want to log the other failed fields as well. Maybe it's an inefficient way but I did something like:
bool findParent = true;
if (ChildOf != "")
{
try
{
RecordRef parentRef = new RecordRef();
parentRef.internalId = searchCustomer(ChildOf);
parentRef.typeSpecified = false;
customer.parent = parentRef;
}
catch
{
findParent = false;
_out.error(customerID + " was not inserted. Error: invalid format Parent string");
}
}
And then an if statement before trying to insert:
if (findPartner == true && findParent == true)
{
response = _service.add(customer);
// Process the response
if (response.status.isSuccess)
{
}
else
{
_out.error(customerID + " was not inserted. Error: " + getStatusDetails(response.status));
}
}
else
{
//_out.error(customerID + " was not updated. Error: " + getStatusDetails(response.status));
}
Use the row.HasError property.
I asked this question yesterday and got a great response/code example. The only problem is that I forgot to mention that I am forced to work with the .Net Framework 2.0 and can't use the List.Select ( I assume the linq namespace). Does anyone have a good work around for List.Select seen below:
class Program
{
struct ProcessStartTimePair
{
public Process Process { get; set; }
public DateTime StartTime { get; set; }
public DateTime ExitTime
{
get
{
return DateTime.Now; // approximate value
}
}
public ProcessStartTimePair(Process p) : this()
{
Process = p;
try
{
StartTime = p.StartTime;
}
catch (System.ComponentModel.Win32Exception)
{
StartTime = DateTime.Now; // approximate value
}
}
}
static void Main(string[] args)
{
SqlConnection cnn = new SqlConnection(#"Data Source=XXXXXX;Initial Catalog=XXXXXX;User ID=XXXX;Password=XXXX");
List<ProcessStartTimePair> knownProcesses = new List<ProcessStartTimePair>();
while (true)
{
foreach (Process p in Process.GetProcesses())
{
if (!knownProcesses.Select(x => x.Process.Id).Contains(p.Id))
{
knownProcesses.Add(new ProcessStartTimePair(p));
//Console.WriteLine("Detected new process: " + p.ProcessName);
}
}
for (int i = 0; i < knownProcesses.Count; i++)
{
ProcessStartTimePair pair = knownProcesses[i];
try
{
if (pair.Process.HasExited)
{
Console.WriteLine(pair.Process.ProcessName + " has exited (alive from {0} to {1}).", pair.StartTime.ToString(), pair.ExitTime.ToString());
knownProcesses.Remove(pair);
i--; // List was modified, 1 item less
// TODO: Store in the info in the database
String sql = "insert into procs (machine,login,process,start_time,end_time) ";
sql += "values ('" + Environment.MachineName + "','" + System.Security.Principal.WindowsIdentity.GetCurrent().Name.ToString().Split('\\')[1] + "','" + pair.Process.ProcessName + "','" + pair.StartTime.ToString() + "','" + pair.ExitTime.ToString() + "');";
SqlCommand cmd = new SqlCommand(sql, cnn);
try
{
cnn.Open();
cmd.ExecuteNonQuery();
}
catch (Exception ex)
{
//Console.WriteLine(ex.Message);
}
finally
{
cnn.Close();
}
}
}
catch (System.ComponentModel.Win32Exception)
{
// Would have to check whether the process still exists in Process.GetProcesses().
// The process probably is a system process.
}
}
//Console.WriteLine();
System.Threading.Thread.Sleep(5000);
}
}
}
I'm not sure the datatype of Id. I'll assume an int, you get the idea:
List<int> idList = new List<int>();
foreach(ProcessStartTimePair proc in knownProcesses)
{
idList.Add(proc.Process.Id);
}
if(idList.Contains(p.Id))
{
// ...
}
You just have to do the work of getting the list of IDs yourself.
Also, it's generally a better idea to edit your original question, and leave comments on the answers of others.
Try this:
if(!knownProcesses.Exists(x => x.Process.Id == p.Id))
Or, if you are using Visual Studio 2005 (not 2008),
if(!knownProcesses.Exists(delegate(ProcessStartTimePair x) { return x.Process.Id == p.Id; }))