I got this error:
Must declare the scalar variable #wachtwoord
I tried to solve it using this post: same error but with no luck so far. I am a bit lost. I want the generate a code for #wachtwoord (password). Then I want to count all the rows in the database. I will use the count for my for statement, in my for statement will be an UPDATE statement to update every row in the database with their own generated password.
If you guys have any advise or a solution for this problem it would be great!
This is my code:
public partial class Form1 : Form
{
string cn = "Data Source=pc-wesley;Initial Catalog=ProjectVoteOrDie;Integrated Security=True";
string cm1 = "UPDATE Test SET wachtwoord = #wachtwoord WHERE id = #id";
string cm2 = "SELECT COUNT(*) FROM Test;";
public Form1()
{
InitializeComponent();
}
private void btnKlik_Click(object sender, EventArgs e)
{
var chars = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789";
var random = new Random();
//random code gen
var result = new string(
Enumerable.Repeat(chars, 8)
.Select(s => s[random.Next(s.Length)])
.ToArray());
SqlConnection scn = new SqlConnection(cn);
SqlCommand scm1 = new SqlCommand(cm1, scn);
SqlCommand scm2 = new SqlCommand(cm2, scn);
try
{
scn.Open();
int rows = Convert.ToInt32(scm2.ExecuteScalar());
scm2.Parameters.Clear();
for (int i = 1; i <= rows; i++)
{
scm1.Parameters.AddWithValue("#wachtwoord", result);
scm1.Parameters.AddWithValue("#id", i);
scm1.Parameters.Clear();
scm1.ExecuteNonQuery();
}
}
catch (Exception se) //got the error on
{
lblRandom.Text = Convert.ToString(se);
}
finally
{
scn.Close();
}
}
Related
I've been developing a C# WPF project with VS2015 using SQL Server Express LocalDb with Entity Framework. I have built a custom seeder for the database, that reads test data from an Excel file, that simply combines the Excel data into a command string, and this is inserted using context.Database.ExecuteSQLCommand.
Now, I was thinking of launching the project with SQL Server Compact Edition 4.0, but I find this command is not working anymore. Do I have to write my uploader again using SqlCeConnection and SqlCeCommand or am I missing something?
Also, from somewhere I have understood that with EF you can switch the SQL provider and the code would not need other changes. Am I in for more surprises down the road?
Example of the uploader command:
string cmd = "INSERT INTO Venues(Name, City, Telephone) Values ('X','Y','Z')"
context.Database.ExecuteSqlCommand(cmd);
The error:
There was an error parsing the query. [ Token line number = 2,Token line offset = 1,Token in error = INSERT ]
This is not just a testing issue, as I would want to include this uploader in the production version, too, for quick inserting of master data (e.g. employee list).
EDIT: Uploader code. If this can be done without resorting to raw SQL, that would be a good solution, too.
This loops through Excel sheets (named after entities) and columns (first row has property name) and rows 2->n (data). This handles the upload of basically any amount of data within Excel limitations. The point is that the code has no knowledge of the entities (might have been possible to parameterize DataContext too). Code might not be optimal, as I'm just a beginner, but has worked for me, except not with SQL CE. Editing to suit CE is not a big issue, but I wanted to ask for possibly better ways.
public static class ExcelUploader
{
static ArrayList data;
static List<string> tableNames;
public static string Upload(string filePath)
{
string result = "";
data = new ArrayList();
tableNames = new List<string>();
ArrayList upLoadData = ReadFile(filePath);
List<string> dataList = ArrayListToStringList(upLoadData);
using (var db = new DataContext())
{
using (var trans = db.Database.BeginTransaction())
{
try
{
foreach (var cmd in dataList)
{
Console.WriteLine(cmd);
db.Database.ExecuteSqlCommand(cmd);
}
db.SaveChanges();
trans.Commit();
}
catch (Exception e)
{
trans.Rollback();
result = e.Message;
MessageBox.Show(result);
}
}
}
return result;
}
private static ArrayList ReadFile(string fileName)
{
List<string> commands = new List<string>();
var xlApp = new Microsoft.Office.Interop.Excel.Application();
var wb = xlApp.Workbooks.Open(fileName, ReadOnly: true);
xlApp.Visible = false;
foreach (Worksheet ws in wb.Worksheets)
{
var r = ws.UsedRange;
var array = r.Value;
data.Add(array);
tableNames.Add(ws.Name);
}
wb.Close(SaveChanges: false);
xlApp.Quit();
return data;
}
private static List<string> ArrayListToStringList(ArrayList arrList)
{
List<string> result = new List<string>();
for(int tableAmount = 0;tableAmount<data.Count;tableAmount++)
{
result.Add(ArrayToSqlCommand(arrList[tableAmount] as Array, tableNames[tableAmount]));
}
return result;
}
private static string ArrayToSqlCommand(Array arr, string tableName)
{
int propertyRow = 1;
int firstDataRow = 2;
string command = "";
// loop rows
for (int rowIndex = firstDataRow; rowIndex <= arr.GetUpperBound(0); rowIndex++)
{
command += "INSERT INTO " + tableName + "(";
//add column names
for (int colIndex = 1; colIndex <= arr.GetUpperBound(1); colIndex++)
{
//get property name
command += arr.GetValue(propertyRow, colIndex);
//add comma if not last column, otherwise close bracket
if (colIndex == arr.GetUpperBound(1))
{
command += ") Values (";
}
else
{
command += ", ";
}
}
//add values
for (int colIndex = 1; colIndex <= arr.GetUpperBound(1); colIndex++)
{
//get property value
command += "'" + arr.GetValue(rowIndex, colIndex) + "'";
//add comma if not last column, otherwise close bracket
if (colIndex == arr.GetUpperBound(1))
{
command += ");";
}
else
{
command += ", ";
}
}
command += "\n";
}
return command;
}
}
There are two ways to use raw SQL queries I'd offer.
Initial data
1) Excel table
+=======+=======+===========+
| Name | City | Telephone |
|===========================|
| Adam | Addr1 | 111-11-11 |
|-------|-------|-----------|
| Peter | Addr2 | 222-22-22 |
+-------+-------+-----------+
2) SQL Server CE table
CREATE TABLE Venues
(
Id int identity primary key,
[Name] nvarchar(100) null,
City nvarchar(100) null,
Telephone nvarchar(100) null
);
3) Getting data from Excel
Here we're interested in getting array from Excel sheet. As soon as we get it, we can safely close Excel. The code assumes file "Employees.xlsx" to be next to executable file.
private object[,] GetExcelData()
{
xlApp = new Excel.Application { Visible = false };
var xlBook =
xlApp.Workbooks.Open(System.IO.Path.Combine(
Environment.CurrentDirectory,
"Employees.xlsx"));
var xlSheet = xlBook.Sheets[1] as Excel.Worksheet;
// For process termination
var xlHwnd = new IntPtr(xlApp.Hwnd);
var xlProc = Process.GetProcesses()
.Where(p => p.MainWindowHandle == xlHwnd)
.First();
// Get Excel data: it's 2-D array with lower bounds as 1.
object[,] arr = xlSheet.Range["A1"].CurrentRegion.Value;
// Shutdown Excel
xlBook.Close();
xlApp.Quit();
xlProc.Kill();
GC.Collect();
GC.WaitForFullGCComplete();
return arr;
}
Now you can use one of the ways to generate query.
Option 1. Use ExecuteSqlCommand
When using ExecuteSqlCommand, it's advisable to use parameterized queries to avoid errors. You can pass explicitly created SqlCeParameter or just pass a value.
private void UseExecuteSqlCommand()
{
object[,] arr = GetExcelData();
using (var db = new EmpContext())
{
db.Database.Initialize(true);
int count = 0;
string sql = "INSERT INTO Venues (Name, City, Telephone) " +
"VALUES (#name, #city, #phone);";
// Start from 2-nd row since we need to skip header
for (int r = 2; r <= arr.GetUpperBound(0); ++r)
{
db.Database.ExecuteSqlCommand(
sql,
new SqlCeParameter("#name", (string)arr[r, 1]),
new SqlCeParameter("#city", (string)arr[r, 2]),
new SqlCeParameter("#phone", (string)arr[r, 3])
);
++count;
}
conn.Close();
MessageBox.Show($"{count} records were saved.");
}
}
Option 2. Use DbConnection
If you want your code to be more generic, you can create method which would accept DbConnection. This will allow to pass either SqlConnection or SqlCeConnection. But the code becomes more verbose because we can't use constructors since these classes are abstract.
private void UseDbConnection()
{
object[,] arr = GetExcelData();
using (var db = new EmpContext())
{
db.Database.Initialize(true);
int count = 0;
string sql = "INSERT INTO Venues (Name, City, Telephone) " +
"VALUES (#name, #city, #phone);";
DbParameter param = null;
DbConnection conn = db.Database.Connection;
conn.Open();
DbCommand command = conn.CreateCommand();
command.CommandText = sql;
command.CommandType = CommandType.Text;
// Create parameters
// Name
param = command.CreateParameter();
param.ParameterName = "#name";
command.Parameters.Add(param);
// City
param = command.CreateParameter();
param.ParameterName = "#city";
command.Parameters.Add(param);
// Telephone
param = command.CreateParameter();
param.ParameterName = "#phone";
command.Parameters.Add(param);
// Start from 2-nd row since we need to skip header
for (int r = 2; r <= arr.GetUpperBound(0); ++r)
{
command.Parameters["#name"].Value = (string)arr[r, 1];
command.Parameters["#city"].Value = (string)arr[r, 2];
command.Parameters["#phone"].Value = (string)arr[r, 3];
command.ExecuteNonQuery();
++count;
}
conn.Close();
MessageBox.Show($"{count} records were saved.");
}
}
You can also use ordinal positions for parameters which eliminates creating parameters names and makes code much shorter:
private void UseDbConnection()
{
object[,] arr = GetExcelData();
using (var db = new EmpContext())
{
db.Database.Initialize(true);
int count = 0;
// Take a note - use '?' as parameters
string sql = "INSERT INTO Venues (Name, City, Telephone) " +
"VALUES (?, ?, ?);";
DbConnection conn = db.Database.Connection;
conn.Open();
DbCommand command = conn.CreateCommand();
command.CommandText = sql;
command.CommandType = CommandType.Text;
// Create parameters
command.Parameters.Add(command.CreateParameter());
command.Parameters.Add(command.CreateParameter());
command.Parameters.Add(command.CreateParameter());
for (int r = 2; r <= arr.GetUpperBound(0); ++r)
{
// Access parameters by position
command.Parameters[0].Value = (string)arr[r, 1];
command.Parameters[1].Value = (string)arr[r, 2];
command.Parameters[2].Value = (string)arr[r, 3];
command.ExecuteNonQuery();
++count;
}
conn.Close();
MessageBox.Show($"{count} records were saved.");
}
}
P.S.
I didn't check whether the underlying connection is opened, but it's a good idea to do so.
Based on JohnyL's excellent input, I was able to modify my code so that it works with either SQL Server Express and and SQL Server CE. I'll put my new code as an answer, as I had to parameterize it further, as I couldn't write the property names in the code either. But this was a simple step, once I got the idea from JohnyL. Not sure though, if the database writing operation should be wrapped inside a DbTransaction, but this worked for now.
public static class ExcelUploader
{
static ArrayList data;
static List<string> tableNames;
static List<DbCommand> cmdList = new List<DbCommand>();
static DbConnection conn;
public static void Upload(string filePath)
{
data = new ArrayList();
tableNames = new List<string>();
//get Excel data to array list
ArrayList upLoadData = ReadFile(filePath);
using (var db = new DataContext())
{
conn = db.Database.Connection;
//transform arraylist into a list of DbCommands
ArrayListToCommandList(upLoadData);
conn.Open();
try
{
foreach (var cmd in cmdList)
{
//Console.WriteLine(cmd.CommandText);
cmd.ExecuteNonQuery();
}
}
catch (Exception e)
{
var result = e.Message;
MessageBox.Show(result);
}
}
}
//opens Excel file and reads worksheets to arraylist
private static ArrayList ReadFile(string fileName)
{
List<string> commands = new List<string>();
var xlApp = new Microsoft.Office.Interop.Excel.Application();
var wb = xlApp.Workbooks.Open(fileName, ReadOnly: true);
xlApp.Visible = false;
foreach (Worksheet ws in wb.Worksheets)
{
var r = ws.UsedRange;
var array = r.Value;
data.Add(array);
tableNames.Add(ws.Name);
}
wb.Close(SaveChanges: false);
xlApp.Quit();
return data;
}
//transforms arraylist to a list of DbCommands
private static void ArrayListToCommandList(ArrayList arrList)
{
List<DbCommand> result = new List<DbCommand>();
for (int tableAmount = 0; tableAmount < data.Count; tableAmount++)
{
ArrayToSqlCommands(arrList[tableAmount] as Array, tableNames[tableAmount]);
}
}
private static void ArrayToSqlCommands(Array arr, string tableName)
{
//Excel row which holds property names
int propertyRow = 1;
//First Excel row with values
int firstDataRow = 2;
string sql = "";
DbCommand cmd = conn.CreateCommand();
sql += "INSERT INTO " + tableName + "(";
//add column names to command text
for (int colIndex = 1; colIndex <= arr.GetUpperBound(1); colIndex++)
{
//get property name
sql += arr.GetValue(propertyRow, colIndex);
//add comma if not last column, otherwise close bracket
if (colIndex == arr.GetUpperBound(1))
{
sql += ") Values (";
}
else
{
sql += ", ";
}
}
//add value parameter names to command text
for (int colIndex = 1; colIndex <= arr.GetUpperBound(1); colIndex++)
{
//get property name
sql += "#" + arr.GetValue(propertyRow, colIndex);
//add comma if not last column, otherwise close bracket
if (colIndex == arr.GetUpperBound(1))
{
sql += ");";
}
else
{
sql += ", ";
}
}
//add data elements as command parameter values
for (int rowIndex = firstDataRow; rowIndex <= arr.GetUpperBound(0); rowIndex++)
{
//initialize command
cmd = conn.CreateCommand();
cmd.CommandText = sql;
cmd.CommandType = CommandType.Text;
for (int colIndex = 1; colIndex <= arr.GetUpperBound(1); colIndex++)
{
//set parameter values
DbParameter param = null;
param = cmd.CreateParameter();
param.ParameterName = "#" + (string)arr.GetValue(propertyRow, colIndex);
cmd.Parameters.Add(param);
cmd.Parameters[param.ParameterName].Value = arr.GetValue(rowIndex, colIndex);
}
//add command to command list
cmdList.Add(cmd);
}
}
}
I'm trying to implement date-picker functionality in my project, but I can't do it quite right. I'm trying to pass the date-picker value in my oracle string so that it will compare with my db column and return results on the date criteria...
Whenever I pass it to the select statement it won't generate errors particularly but on button click it doesn't perform anything except it shows "not connected".
str = "Select * from sania.doctor where APPOINTMENT_DATE = "+ datepicker1.value;
It is clear it is logical mistake but I'm new to this C# concepts I need someone to tell me how to pass it and then display the results as well.
private void button1_Click(object sender, EventArgs e)
try
{
OracleCommand com;
OracleDataAdapter oda;
string ConString = "Data Source=XE;User Id=system;Password=sania;";
OracleConnection con = new OracleConnection(ConString);
{
// string id = dateTimePicker1.Text.Trim();
con.Open();
// str = "Select * from sania.doctor where APPOINTMENT_DATE = " + dateTimePicker1.value;
str = "select * from sania.doctor where APPOINTMENT_DATE to_date('"+dateTimePicker1.Value.ToString("yyyyMMdd") + "', 'yyyymmdd')";
com = new OracleCommand(str);
oda = new OracleDataAdapter(com.CommandText, con);
dt = new DataTable();
oda.Fill(dt);
Rowcount = dt.Rows.Count;
//int val = 0;
for (int i = 0; i < Rowcount; i++)
{
dt.Rows[i]["APPOINTMENT_DATE"].ToString();
//if (id == dateTimePicker1.Value)// this LINE SHOWS ERROR--because it is a string and I am using date with it. Don't know conversion
// {
// val = 1;
//}
}
// if (val == 0)
// { MessageBox.Show("INVALID ID"); }
// else
// {
DataSet ds = new DataSet();
oda.Fill(ds);
if (ds.Tables.Count > 0)
{
dataGridView1.DataSource = ds.Tables[0].DefaultView;
}
else { MessageBox.Show("NO RECORDS FOUND"); }
}
}
//}
catch (Exception)
{ MessageBox.Show("not connected"); }
}
Do not put values into SQL directly, use bind variables/parametes instead. For Oracle:
// :prm_Appointment_Date bind variable declared within the query
String str =
#"select *
from sania.doctor
where Appointment_Date = :prm_Appointment_Date";
....
using(OracleCommand q = new OracleCommand(MyConnection)) {
q.CommandText = str;
// datepicker1.Value passed into :prm_Appointment_Date via parameter
q.Parameters.Add(":prm_Appointment_Date", datepicker1.Value);
...
}
Doing like that you can be safe from either SQL Injection or Format/Culture differences
A few months ago I made a test program for a project and everything worked fine there.
Now I am working on the program itself, so I copied the code from the test program and
changed the the names of the columns,buttons etc. so it would fit the current program.
When I try to add something into the database it does nothing on the first click, on the
second pops up an error which says that the connection is open.. I really got no idea what's
the problem. I tried to check again if I made a mistake in a column name or the database name
but everything seems to be correct.
Note: I also have a function that show data from the database and it works without any problem.
private void InsertData()
{
string NewCode = GenerateCode();
string NewSentence = txtSentence.Text;
string NewRow = NewRowNum();
try
{
string AddData = "INSERT INTO ShopSentences (BinaryStrings,Sentence,RowNumber) VALUES (#NewBinaryString,#NewSentence,#NewRowNumber)";
SqlCommand DataAdd = new SqlCommand(AddData, Connection);
DataAdd.Parameters.AddWithValue("#NewBinaryString", NewCode);
DataAdd.Parameters.AddWithValue("#NewNewSentence", NewSentence);
DataAdd.Parameters.AddWithValue("#NewRowNumber", NewRow);
Connection.Open();
DataAdd.ExecuteNonQuery();
Connection.Close();
}
catch (Exception e)
{
Console.WriteLine(e.ToString());
}
}
//Checking the banary code in the last row
string GenerateCode()
{
string RowNo = RowFind();
int Row = int.Parse(RowNo);
int Code = Row + 1;
string Cd = Convert.ToString(Code, 2);
int Ln = Cd.Trim().Length;
if (Ln == 3)
{
Cd = "100" + Cd;
}
else if (Ln == 4)
{
Cd = "10" + Cd;
}
else if (Ln == 5)
{
Cd = "1" + Cd;
}
return Cd;
}
//Finding the last row
string RowFind()
{
Connection.Open();
string queryString = string.Format("SELECT * FROM ShopSentences");
SqlDataAdapter sda = new SqlDataAdapter(queryString, Connection);
DataTable dt = new DataTable("ShopSentences");
sda.Fill(dt);
Connection.Close();
return dt.Rows[dt.Rows.Count - 1]["RowNumber"].ToString();
}
string NewRowNum()
{
string Row = RowFind();
int CalcRow = int.Parse(Row) + 1;
Row = CalcRow.ToString();
return Row;
}
The connection that appears to be open is the one in the string RowFind().
Here are the other related things to the database:
public partial class frmShop : Form
{
System.Data.SqlClient.SqlConnection Connection;
public frmShop()
{
string DatabaseConnection = WindowsFormsApplication1.Properties.Settings.Default.BinaryStringsDictionaryConnectionString1;
Connection = new System.Data.SqlClient.SqlConnection();
Connection.ConnectionString = DatabaseConnection;
InitializeComponent();
}
private void frmShop_Load(object sender, EventArgs e)
{
// TODO: This line of code loads data into the 'binaryStringsDictionaryDataSet.ShopSentences' table. You can move, or remove it, as needed.
this.shopSentencesTableAdapter.Fill(this.binaryStringsDictionaryDataSet.ShopSentences);
}
private void GetSentence()
{
try
{
Connection.Open();
SqlDataReader ReadSentence = null;
Int32 BinaryInt = Int32.Parse(txtBinaryString.Text);
string CommandString = "SELECT Sentence FROM ShopSentences WHERE BinaryStrings = #BinaryString";
SqlCommand Command = new SqlCommand(CommandString, Connection);
Command.Parameters.Add("#BinaryString", System.Data.SqlDbType.Int).Value = BinaryInt;
ReadSentence = Command.ExecuteReader();
while (ReadSentence.Read())
{
txtSentence.Text = (ReadSentence["Sentence"].ToString());
Fit = 1;
}
Connection.Close();
}
catch (Exception e)
{
Console.WriteLine(e.ToString());
}
}
}
You are getting errors because you are reusing the same connection Connection.Open(); several times.
Your method InsertData() is doing this 3 times in the same method.
You should create a new instance of the connection object and dispose it on your methods.
Using Statement are the way to go.
private void InsertData()
{
using (var Connection = new SqlConnection(DatabaseConnection))
{
string NewCode = GenerateCode();
string NewSentence = txtSentence.Text;
string NewRow = NewRowNum();
try
{
Connection.Open();
string AddData = "INSERT INTO ShopSentences (BinaryStrings,Sentence,RowNumber) VALUES (#NewBinaryString,#NewSentence,#NewRowNumber)";
SqlCommand DataAdd = new SqlCommand(AddData, Connection);
DataAdd.Parameters.AddWithValue("#NewBinaryString", NewCode);
DataAdd.Parameters.AddWithValue("#NewNewSentence", NewSentence);
DataAdd.Parameters.AddWithValue("#NewRowNumber", NewRow);
DataAdd.ExecuteNonQuery();
//Connection.Close(); no need to close
}
catch (Exception e)
{
Console.WriteLine(e.ToString());
}
}
}
You can save one more connection if you store the row returned by RowFind()
string RowFind()
{
using (var Connection = new SqlConnection(DatabaseConnection))
{
Connection.Open();
string queryString = string.Format("SELECT * FROM ShopSentences");
SqlDataAdapter sda = new SqlDataAdapter(queryString, Connection);
DataTable dt = new DataTable("ShopSentences");
sda.Fill(dt);
//Connection.Close();
return dt.Rows[dt.Rows.Count - 1]["RowNumber"].ToString();
}
}
So you would connect once instead of twice:
var Row = RowFind();
string NewCode = GenerateCode(Row);
string NewRow = NewRowNum(Row);
string NewSentence = txtSentence.Text;
Declare your connection string variable to a property so you can reuse it:
private string DatabaseConnection {get; set;}
Instead using an instance level SqlConnection you should only provide a common factory for creating a connection:
public partial class frmShop : Form
{
private string ConnectionString
{
get { return WindowsFormsApplication1.Properties.Settings.Default.BinaryStringsDictionaryConnectionString1; }
}
public frmShop()
{
InitializeComponent();
}
private SqlConnection CreateConnection()
{
var conn = new SqlConnection(ConnectionString);
conn.Open();
return conn;
}
private void frmShop_Load(object sender, EventArgs e)
{
// TODO: This line of code loads data into the 'binaryStringsDictionaryDataSet.ShopSentences' table. You can move, or remove it, as needed.
this.shopSentencesTableAdapter.Fill(this.binaryStringsDictionaryDataSet.ShopSentences);
}
private void GetSentence()
{
try
{
using (var conn = CreateConnection())
{
var BinaryInt = int.Parse(txtBinaryString.Text);
var commandString = "SELECT Sentence FROM ShopSentences WHERE BinaryStrings = #BinaryString";
using (var Command = new SqlCommand(commandString, conn))
{
Command.Parameters.Add("#BinaryString", System.Data.SqlDbType.Int).Value = BinaryInt;
using (var readSentence = Command.ExecuteReader())
{
while (readSentence.Read())
{
txtSentence.Text = (readSentence["Sentence"].ToString());
Fit = 1;
}
}
}
}
}
catch (Exception e)
{
Console.WriteLine(e.ToString());
}
}
private void InsertData()
{
try
{
using (var conn = CreateConnection())
{
var commandString = "INSERT INTO ShopSentences (BinaryStrings,Sentence,RowNumber) VALUES (#NewBinaryString,#NewSentence,#NewRowNumber)";
using (var comm = new SqlCommand(commandString, conn))
{
comm.Parameters.AddWithValue("#NewBinaryString", GenerateCode());
comm.Parameters.AddWithValue("#NewNewSentence", txtSentence.Text);
comm.Parameters.AddWithValue("#NewRowNumber", NewRowNum());
comm.ExecuteNonQuery();
}
}
}
catch (Exception e)
{
Console.WriteLine(e.ToString());
}
}
//Checking the banary code in the last row
string GenerateCode()
{
string RowNo = RowFind();
int Row = int.Parse(RowNo);
int Code = Row + 1;
string Cd = Convert.ToString(Code, 2);
int Ln = Cd.Trim().Length;
if (Ln == 3)
{
Cd = "100" + Cd;
}
else if (Ln == 4)
{
Cd = "10" + Cd;
}
else if (Ln == 5)
{
Cd = "1" + Cd;
}
return Cd;
}
//Finding the last row
string RowFind()
{
using (var conn = CreateConnection())
{
var commandString = "SELECT * FROM ShopSentences";
using (var comm = new SqlCommand(commandString, conn))
{
using (var sda = new SqlDataAdapter(queryString, Connection))
{
using (DataTable dt = new DataTable("ShopSentences"))
{
sda.Fill(dt);
return dt.Rows[dt.Rows.Count - 1]["RowNumber"].ToString();
}
}
}
}
}
string NewRowNum()
{
var Row = RowFind();
var CalcRow = int.Parse(Row) + 1;
return CalcRow.ToString();
}
}
But this is just the beginning you should not have any hard SQL dependency in your Form classes.
When sharing same SqlConnection instance several times in your code, instead of directly opening the you can rather check the connection state first and then open it if not already opened. For example:
if(Connection.State!= ConnectionState.Open)
Connection.Open();
This is a bit weird to me.
I have the following code:
public static object[,] dbMultipleSingleQueries(string strDBPath, object[] oSQL)
{
//This is needed for attaching a DB.
object[,] objOut;
objOut = new Object[1, 1];
try
{
//Prepare DB connection string
strDBPath = "Data Source=" +
#strDBPath +
";Version=3";
//SQL Objs
SQLiteConnection dbConnection = new SQLiteConnection(strDBPath);
SQLiteCommand dbCommand = null;
SQLiteDataAdapter dbAdapter = null;
DataTable table = new DataTable();
//For looping
int j = 0;
//Conn str
dbConnection.Open();
dbCommand = new SQLiteCommand(dbConnection);
while (j < oSQL.Length)
{
try
{
dbCommand.CommandText = oSQL[j].ToString();
dbCommand.CommandType = System.Data.CommandType.Text;
if (j == (oSQL.Length - 1))
{
dbAdapter = new SQLiteDataAdapter(dbCommand);
dbAdapter.Fill(table);
objOut = table2Array(table);
}
else
{
dbCommand.ExecuteNonQuery();
objOut[0, 0] = "Success!";
}
}
catch (Exception e2)
{
System.Console.WriteLine(e2.StackTrace.ToString());
objOut[0, 0] = e2.StackTrace.ToString();
}
j++;
};
dbConnection.Close();
dbConnection = null;
}
catch (Exception e)
{
objOut[0, 0] = e.StackTrace.ToString();
}
return objOut;
}
which works perfectly if i feed my arguments from a spreadsheet like this:
o = Application.Run("dbMultipleSingleQueries", "20130201.db", [test])
where [test] is a range in my workbook with queries that work and look something like this:
attach database 'a.db' as d1
select * from d1.main
now if i do the following in vba
Option Explicit
Sub Main()
Dim sql(1 To 2, 1 To 1)
sql(1, 1) = "attach database 'a.db' as d1"
sql(2, 1) = "select * from d1.main"
o = Application.Run("dbMultipleSingleQueries", "20130201.db", sql)
End Sub
this does not work. i get a "Type Mismatch" error. Any input why would be a huge help this is driving me nuts!
Your function prototype specifies that the second argument needs to be of type "Object[]" - but you are passing a variant that probably thinks it is a string array, based on the assignment.
I have following code (this is just for demonstration, I won't paste all lines)
public static class SearchAndEdit
{
public static string[] SearchAndDisplay(string code)
{
string SQLconnection = WebConfigurationManager.ConnectionStrings["DatabaseConnectionString"].ConnectionString;
string[] field;
field = new string[6];
if (code == "")
{
field[0] = "Nothing to search";
}
else
{
string SQLSelect = "SELECT user_name, user_surname, user_code, user_group, user_password FROM Users WHERE user_code=#user_code";
SqlConnection connect = new SqlConnection(SQLconnection);
SqlCommand search = new SqlCommand(SQLSelect, connect);
search.Parameters.Clear();
search.Parameters.AddWithValue("#user_code", code);
try
{
connect.Open();
SqlDataReader info = search.ExecuteReader();
if (info.HasRows)
{
field[0] = "Data loaded";
}
}
finally
{
connect.Close();
}
}
return field;
}
}
Then I use it in Code behind file (*aspx.cs).
protected void Search_click(object sender, EventArgs e)
{
string[] information = SearchAndEdit.SearchAndDisplay(searchBox.Text);
for (int i = 0; i < information.Length; i++)
{
name.Text += information[i];
}
}
However, the code returns nothing (label name is empty), even exception is not thrown. Any idea where is the catch ? Thanks.
try this
if(string.IsNullOrEmpty(code))
{
field[0] = "Empty box";
}
you changed the post. you should have this instead
string SQLconnection = WebConfigurationManager.ConnectionStrings["DatabaseConnectionString"].ConnectionString;
string[] field;
field = new string[6];
field[0] = "Nothing to search"; // add here in case string is null
if (!string.IsNullOrEmpty(code))
{
string SQLSelect = "SELECT user_name, user_surname, user_code, user_group, user_password FROM Users WHERE user_code=#user_code";
SqlConnection connect = new SqlConnection(SQLconnection);
SqlCommand search = new SqlCommand(SQLSelect, connect);
search.Parameters.Clear();
search.Parameters.AddWithValue("#user_code", code);
try
{
connect.Open();
SqlDataReader info = search.ExecuteReader();
if (info.HasRows)
{
field[0] = "Data loaded";
}
}
catch
{
// error handle here problem with connection
}
finally
{
connect.Close();
}
}
return field;
Well, now that you've shown us more code: if the SQL query returns 0 rows, then the returned array will be empty, as you observe. Therefore, it seems that the values you're passing in for user_code aren't in the database -- or perhaps they're of the wrong data type.
You should try stepping through this with a debugger. There is a case where the field array will return an array of six null string elements: if code is not an empty string, the else clause will execute, and if your SQL query returns no rows, then field will never receive any string values. My guess is that this is what's happening. If you can't use a debugger for some reason (?), you can always modify your code thusly:
if (info.HasRows) {
field[0] = "Data loaded";
} else {
field[0] = "No data found";
}