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SQL Ntext Items Only Having the First Two Chars Read in

I am currently programming a C# program that lets students log into an interface, check grades, etc.. Admins can create new users. The student IDs are 9-digit codes that all begin with "95." When an admin is creating a new user, I want to go through the database to make sure that the ID number they have entered isn't already taken.
To do this, I have the following code:
connection.Open();
readerUsers = commandUsers.ExecuteReader();
while (readerUsers.Read())
{
MessageBox.Show(readerUsers[2].ToString());
if(readerUsers[2].ToString() == IDNum)
{
userAlreadyExists = true;
break;
}
}
connection.Close();
And in my Users table, which readerUsers and commandUsers are connected to, I have the following:
IDuser Username 95Number Password Active Admin
-------------------------------------------------------------
1 sward 951619984 uo99lb True True
... ... ... ... ... ...
Now, when I went to test my code by creating a user with the ID number of 951619984 (a number already entered in the database), userAlreadyExists would still remain false. So I made the program show a message box of each item in the 95Number column (which is of type Ntext). Every time, the message box would only show "95".
I am very new to programming with databases, so I apologize if this is a very newby question, but I'm not sure what to do to get the whole string from this ntext column. Could someone explain what I'm doing wrong? Thank you for your time.

Here is a better way of doing that:
var connstr = ConfigurationManager.ConnectionStrings["your key"].ConnectionString;
var sql = "SELECT COUNT(*) FROM Users WHERE [95number]=#num";
using (var conn = new SqlConnection(connstr))
using (var cmd = new SqlCommand(sql, conn))
{
cmd.Parameters.Add("num",SqlDbType.Int).Value = IDNum;
conn.Open();
var result = cmd.ExecuteScalar();
userAlreadyExists = result > 0;
}

I did mines this way.
string Qstring = "Select 95number where 95number = '95#########'";
using (SqlConnection Con = new SqlConnection(Form1.ConnectionStringGen))
using (SqlCommand Com = con.CreateCommand())
{
Com.CommandText = Qstring;
con.Open();
using (SqlDataReader Reader = Com.ExecuteReader())
{
if(Reader.Read())
{
string 95Numb = Reader["95Number"].ToString();
Messagebox.show(95Numb);
userAlreadyExists = true;
//meaning if the reader reads an item it will prompt
}
else
{
userAlreadyExists = false;
}
}
con.Close();
}
}
catch (Exception)
{
throw;
}

How do I take sql results and populate labels in my header?

I am attempting to change my code. I am in the process of learning while I code and many parts of my C#/ASP.Net application use LINQ to SQL and many parts use commands to directly access the sql database. I felt like I should standardize these, so I am changing over the LINQ to SQL code. I have a portion of the code that takes the finds one record based on a session variable and then populates the labels in my header with the sql query results. here is the code:
protected void Page_Load(object sender, EventArgs e)
{
var pinNum = MySession.Current.focusParcel;
if (pinNum != 0)
{
String sql = ConfigurationManager.ConnectionStrings["Recorder"].ConnectionString;
SqlConnection connection = new SqlConnection(sql);
connection.Open();
SqlCommand command = new SqlCommand("Select PARCEL, PIN_TXT, Owner, Address1, Address2, CSZ, ACRES, LEGAL, Active FROM[ParcelView] WHERE PARCEL = " + pinNum, connection);
SqlDataReader selectedParcel = command.ExecuteReader();
if (selectedParcel != null)
{
lblPIN_Num.Text = selectedParcel["PARCEL"].ToString();
lblPIN_TXT.Text = selectedParcel["PIN_TXT"].ToString();
lblDateTime.Text = DateTime.Now.ToString("MMMM dd, yyyy");
lblOwner.Text = selectedParcel["Owner"].ToString();
lblAddress1.Text = selectedParcel["Address1"].ToString();
lblAddress2.Text = selectedParcel["Address2"].ToString();
lblCSZ.Text = selectedParcel["CSZ"].ToString();
lblAcres.Text = string.Format("{0} Acres", selectedParcel["ACRES"]);
lblLegal.Text = selectedParcel["LEGAL"].ToString();
if (selectedParcel["Active"].ToString() == "A")
{
lblInactive.Text = " (ACTIVE)";
}
else
{
lblInactive.Text = " (INACTIVE)";
lnkAddDocument.Visible = false;
}
}
lblCurrentUser.Text = Page.User.Identity.Name;
connection.Close();
}
else
Response.Redirect("./ParcelSearch.aspx");
}
I am receiving the following error:
Invalid attempt to read when no data is present.
I know the SQL statement used will return a record when it is used directly into sql query of database.
Thanks in advance for any advice. Should I be concerned about the lack of consistency in accessing data across the application at all? If so, should I be converting everything to LINQ? Or converting everything away from LINQ? I klnow of the existence of MVC and know I should learn it and use it, but I am too far down the path to try to convert there right now.

Change
if (selectedParcel != null)
To
if (selectedParcel.Read())
You have to read a record in the data reader before you can start pulling data. Its a forward only cursor that starts off not pointing to a record. The Read() method advances the reader by 1 and returns true/false if it was successful.
Note that it is not necessary to call HasRows if use the code above. The if block will only be entered if there is a row, if there is not then Read returns false and the block is not entered.
Edit
There are many bad practices in your code.
Use parameterized sql!! This is the most important thing you can take away here!
Wrap your connections in using blocks to ensure the connection is ALWAYS closed.
Sql code changes
String sql = ConfigurationManager.ConnectionStrings["Recorder"].ConnectionString;
using(SqlConnection connection = new SqlConnection(sql))
using(SqlCommand command = new SqlCommand("Select PARCEL, PIN_TXT, Owner, Address1, Address2, CSZ, ACRES, LEGAL, Active FROM [ParcelView] WHERE PARCEL = #pinNum", connection))
{
command.Parameters.Add(new SqlParameter("#pinNum", SqlDbType.VarChar){Value = pinNum});
connection.Open();
using(SqlDataReader selectedParcel = command.ExecuteReader())
{
if (selectedParcel.Read())
{
/*code unchanged*/
}
}
/* 1 line code unchanged*/
}

Once you have executed the command you need to actually read the data :
SqlDataReader selectedParcel = command.ExecuteReader();
if (selectedParcel.HasRows)
{
selectedParcel.Read();
....
....

I recommend you use this format for your sqlDatareader instead, as it it will parse whether results have been retrieved or not, and will automatically dispose itself on exception:
using(SqlDataReader selectedParcel = command.ExecuteReader())
{
while (selectedParcel .Read())
{
//Assign label text to results
}
}

You should Read() the SqlDataReader.
protected void Page_Load(object sender, EventArgs e)
{
var pinNum = MySession.Current.focusParcel;
if (pinNum == 0)
Response.Redirect("./ParcelSearch.aspx");
String sql = ConfigurationManager.ConnectionStrings["Recorder"].ConnectionString;
using(SqlConnection connection = new SqlConnection(sql))
{
connection.Open();
SqlCommand command = new SqlCommand("Select PARCEL, PIN_TXT, Owner, Address1, Address2, CSZ, ACRES, LEGAL, Active FROM[ParcelView] WHERE PARCEL =#PinNum ", connection);
//protect from sql injection
command.Parameters.AddWithValue(#PinNum, pinNum);
using(SqlDataReader selectedParcel = command.ExecuteReader())
{
if(!selectedParcel.HasRows)
return;
SetLabels(selectedParcel);
}
}
}
private void SetLabels(SqlDataReader selectedParcel)
{
lblPIN_Num.Text = selectedParcel["PARCEL"].ToString();
lblPIN_TXT.Text = selectedParcel["PIN_TXT"].ToString();
lblDateTime.Text = DateTime.Now.ToString("MMMM dd, yyyy");
lblOwner.Text = selectedParcel["Owner"].ToString();
lblAddress1.Text = selectedParcel["Address1"].ToString();
lblAddress2.Text = selectedParcel["Address2"].ToString();
lblCSZ.Text = selectedParcel["CSZ"].ToString();
lblAcres.Text = string.Format("{0} Acres", selectedParcel["ACRES"]);
lblLegal.Text = selectedParcel["LEGAL"].ToString();
if (selectedParcel["Active"].ToString() == "A")
{
lblInactive.Text = " (ACTIVE)";
}
else
{
lblInactive.Text = " (INACTIVE)";
lnkAddDocument.Visible = false;
}
lblCurrentUser.Text = Page.User.Identity.Name;
}
I refactor your code to look a little bit. You had different problems as not closing your Reader. You was open to sql injection, also you should transfer the connection to Db in separate class.

Retrieving an element from a created list

I created an list named 'PTNList', and everything I needed added to it just fine. Now I am attempting to write code to retrieve each element from that list and run it against an SQL query. I have a feeling I'm not sure exactly how to about this. The CompareNumbers.txt file generates, but nothing is printed to it. Any help is greatly appreciated.
Below is the section of code I believe needs to be worked with.
using (FileStream fs = new FileStream("c:/temp/CompareNumbers.txt", FileMode.Append, FileAccess.Write))
using (StreamWriter sw = new StreamWriter(fs))
foreach (var ptn in PTNList)
{
//create sql for getting the count using "ptn" as the variable thats changing
//call DB with sql
//Get count from query, write it out to a file;
Console.WriteLine("Running Query");
string query2 = #"SELECT COUNT(PRODUCT_TYPE_NO)
AS NumberOfProducts
FROM dbo.PRODUCT
Where PRODUCT_TYPE_NO = " + ptn;
SqlCommand cmd2 = new SqlCommand(query2);
cmd2.Connection = con;
rdr = cmd2.ExecuteReader();
while (rdr.Read())
{
sw.WriteLine(rdr["NumberOfProducts"]);
}
rdr.Close();
}

You haven't used apostrophes around the values. But you should use parameters anyway. You could use one query instead of one for every type. For example with this approach:
string sql = #"SELECT COUNT(PRODUCT_TYPE_NO) AS NumberOfProducts
FROM dbo.PRODUCT
Where PRODUCT_TYPE_NO IN ({0});";
string[] paramNames = PTNList.Select(
(s, i) => "#type" + i.ToString()
).ToArray();
string inClause = string.Join(",", paramNames);
using (SqlCommand cmd = new SqlCommand(string.Format(sql, inClause)))
{
for (int i = 0; i < paramNames.Length; i++)
{
cmd.Parameters.AddWithValue(paramNames[i], PTNList[i]);
}
// con.Open(); // if not already open
int numberOfProducts = (int) cmd.ExecuteScalar();
}
Update: maybe you really just want to loop them and get their count. Then you don't need this complex approach. But you should still use sql-parameters to prevent sql-injection and other issues like missing apostrophes etc.

You'll want to convert the column back to a type, e.g.
sw.WriteLine(rdr["NumberOfProducts"] as string);
Also, note that your query is prone to SqlInjection attacks and should be parameterized, and that SqlCommand is also disposable. You can squeeze a bit more performance by reusing the SqlCommand:
string query2 = #"SELECT COUNT(PRODUCT_TYPE_NO)
AS NumberOfProducts
FROM dbo.PRODUCT
Where PRODUCT_TYPE_NO = #ptn";
using (var cmd2 = new SqlCommand(query2))
{
cmd2.Connection = con;
cmd2.Parameters.Add("#ptn", SqlDbType.Varchar);
foreach (var ptn in PTNList)
{
cmd2.Parameters["#ptn"].Value = ptn;
Console.WriteLine("Running Query");
using var (rdr = cmd2.ExecuteReader())
{
if (rdr.Read())
{
sw.WriteLine(rdr["NumberOfProducts"] as string);
}
}
}
}

Are you sure your query give an result and sw.WriteLine is executed? I would redesign your code like this, becfause if you have an error in your data query, you might get into trouble. I always like to use this (schema):
IDataReader reader = null;
try
{
// create every thing...
}
catch(Exception ex)
{
// catch all exceptions
}
finally()
{
if(reader != null)
{
reader.Close();
}
}
And use the same for your connection, so that you can be sure, it is closed correct.

Insert Sql function is not working

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.

Execute Select with more than one column and assign to Labels

I am working on a way to be able to run a SELECT Statement that returns more than one value into two different labels on my application.
The idea is to be able to get some version information from the database by running a select on the DB picked, I got the code to work but I know it's super sloppy and im just not really sure how to clean it up. I know there has to be a better way than what I have going on here.
// Update Version & Version2
string sqlCom1 = String.Format(#"SELECT [Version]
FROM ConfigSystem");
string sqlCom = String.Format(#"SELECT Version2
FROM ConfigSystem");
SqlConnectionStringBuilder ConnectionString = new SqlConnectionStringBuilder();
ConnectionString.DataSource = "SQL06";
ConnectionString.InitialCatalog = "SuperSweetDB";
ConnectionString.IntegratedSecurity = true;
SqlConnection cnn;
cnn = new SqlConnection(ConnectionString.ToString());
using (var version = new SqlCommand(sqlCom1, cnn))
{
cnn.Open();
label.Text = (string)version.ExecuteScalar();
cnn.Close();
};
using (var version = new SqlCommand(sqlCom, cnn))
{
cnn.Open();
label2.Text = (string)version.ExecuteScalar();
};
I think, and I'm not certain, that I am opening to connections to get data that I could easily get in SQL with one. The issue that it returns to columns worth of data and I have not been able to find it in Google on how to handle this. (I'm probably looking for the wrong thing)
I only did it this way because I really needed it to work, now I'm trying to clean everything up.
Just a heads up, Fairly new to C# or anything that is not SQL.
Any help is appreciated, if this is a duplicate question I apologize.

You can separate your 2 SQL statements with a semi-colon in 1 string variable, and then use the NextResult() method on the SqlDataReader to get multiple resultsets back.
I updated your code to work. See below. Notice the use of using keyword automatically disposes off the resources after code execution. I tested the code using SQL Server built in variables in 2 sql statements, which are commented.
You should be able to paste the following code in a console app and run it successfully.
using System;
using System.Collections.Generic;
using System.Data.SqlClient;
using System.Linq;
using System.Text;
namespace SqlMultipleResultsets
{
class Program
{
static void Main(string[] args)
{
SqlConnectionStringBuilder ConnectionString = new SqlConnectionStringBuilder();
ConnectionString.DataSource = "SQL06";
ConnectionString.InitialCatalog = "SuperSweetDB";
//ConnectionString.DataSource = "(localdb)\\Projects";
//ConnectionString.InitialCatalog = "tempdb";
ConnectionString.IntegratedSecurity = true;
string sqlSelect = #"SELECT [Version] FROM ConfigSystem;" +
#"SELECT Version2 FROM ConfigSystem";
// string sqlSelect = #"SELECT [Version] = ##VERSION;"
// + #"SELECT Version2 = ##LANGUAGE;" ;
int recordCount;
using (SqlConnection cnn = new SqlConnection(ConnectionString.ToString()))
{
using (SqlCommand command = new SqlCommand(sqlSelect, cnn))
{
cnn.Open( );
SqlDataReader dr = command.ExecuteReader( );
recordCount = 0;
do
{
Console.WriteLine("Result set: {0}", ++recordCount);
while (dr.Read( ))
{
Console.WriteLine("Version: {0}", dr[0]);
}
Console.WriteLine(Environment.NewLine);
}
while (dr.NextResult( ));
} // END command
} // END connection
Console.Write("Press a key to exit...");
Console.ReadKey();
} // END Main
}
}

You could create the SqlCommand only once and reuse it - you can set the command dynamically:
using (var version = new SqlCommand())
{
version.CommandType = CommandType.Text;
version.Connection = cnn;
cnn.Open();
version.CommandText = sqlCom1;
label.Text = (string)version.ExecuteScalar();
version.CommandText = sqlCom2;
label2.Text = (string)version.ExecuteScalar();
cnn.Close();
};
There are a lot of examples in the official SqlCommand class documentation at MSDN.

Here is the answer that I came up with in case anyone needs help on this in the future:
string sqlCom = String.Format(#"SELECT [Version],version2 FROM ConfigSystem");
SqlConnectionStringBuilder ConnectionString = new SqlConnectionStringBuilder();
ConnectionString.DataSource = SQL06;
ConnectionString.InitialCatalog = "SuperSweetdb";
ConnectionString.IntegratedSecurity = true;
SqlConnection cnn = new SqlConnection(ConnectionString.ToString());
using (var version = new SqlCommand(sqlCom, cnn))
{
cnn.Open();
using(IDataReader dataReader = version.ExecuteReader())
{
while (dataReader.Read())
{
label7.Text = dataReader["Version"].ToString();
label9.Text = dataReader["VertexDataVersion"].ToString();
}
}
};
What I ended up doing was breaking it down with datareader. This was kind of difficult to figure out and required a lot of tinkering but in the end it's a cleaner connection that prior to what I had.
Basically DataReader is what I was looking for.
Here is a link to something that helped out quite e bit: Invalid attempt to read when no data is present
As well as this: Multiple SQL queries asp.net c#
Hopefully anyone who has a similar problem will be able to get some help from this.