Develop Reference

How to know when SQL query has finished

I´m trying to create a logic to update massively the column "Prices" from table "Products".
This logic is made, but in my C# code I send the command to the MS Access DB, and immediately I want to show the new results.
The problem is that the update query takes a few seconds to finish, and my C# instantaneously asks for the Select from Products, showing no changes.
The main question is how I can know when the update has finished to show the new results in the grid.
Here my code:
private void btnAceptar_Click(object sender, EventArgs e)
{
string operator;
int code = Convert.ToInt32(cmbcode .SelectedValue);
int material = Convert.ToInt32(cmbMaterial.SelectedValue);
int productType= Convert.ToInt32(cmbproductType.SelectedValue);
if (cmboperating.SelectedIndex == 0){ operator= "+"; }
else if (cmboperating.SelectedIndex == 1) { operator= "-"; }
else if (cmboperating.SelectedIndex == 2) { operator= "*"; }
else { operator= "/"; }
if(txtValoroperating.Text != "") { txtValoroperating.Text = (txtValoroperating.Text).Replace(",", "."); }
string operating = txtValoroperating.Text;
if(rdPrecioDeLista.Checked == true & cbTodasPiezas.Checked == true)
{
//Here is my problem
oProductsDAL.modifyPricesMassively(operating, operator);
txtValoroperating.Text = null;
fillGridProducts();
}
}
And oProductsDAL.modifyPricesMassively(operating, operator) does this:
public bool modifyPricesMassively(operating, operator)
{
if (operating!= "" & operator!= "")
{
return conexion.executeMethod("UPDATE Piezas SET Precio = Precio " +operator+" " +operating);
}
else
{
return false;
}
}
conexion.executeMethod does this:
public bool conexion.executeMethod(string strComando)
{
try
{
OleDbCommand Comando = new OleDbCommand();
Comando.CommandText = strComando;
Comando.Connection = this.establecerConexion();
Conexion.Open();
Comando.ExecuteNonQuery();
Conexion.Close();
return true;
}
catch (Exception ex)
{
MessageBox.Show("No se pudo establecer conexion con la base de datos" +ex);
return false;
}
}
I wish to show a progress bar or a gif loading icon.

c# BeginInvoke doesn't work

I have this code
private delegate void InvokeDelegate();
private void OpenFormNewNote(object sender, FileSystemEventArgs e)
{
if(loop == 2)
{
string service = null;
if (currentServiceName != null)
{
service = currentServiceName.Replace(" ", "");
}
NewNotePanel newNote = new NewNotePanel(e.FullPath, service, listOfService, Path, MyConn, ipAddress, imgFolder, Utente_id);
newNote.TopMost = true;
watcher.EnableRaisingEvents = false;
var result = newNote.ShowDialog();
if(result == DialogResult.OK || result == DialogResult.Cancel)
{
watcher.EnableRaisingEvents = true;
if(result == DialogResult.OK)
{
this.BeginInvoke(new InvokeDelegate(Refresh));
}
}
loop = 0;
}
else
{
loop++;
}
}
And this is the Refresh() Function:
public void Refresh()
{
noteContainer.Controls.Clear();
page = 0;
try
{
string Query = "SELECT a, v, b, cFROM note Where Servizio_ID = " + asd+ " AND Visibile = 1 order by ID desc limit 15 OFFSET " + (pageIndex * page) + " ;";
MySqlCommand MyCommand = new MySqlCommand(Query, MyConn);
MySqlDataReader MyReader;
if (MyConn.State == ConnectionState.Open)
{
MyReader = MyCommand.ExecuteReader();// Here our query will be executed and data saved into the database.
while (MyReader.Read())
{
CreateNotePreview(MyReader.GetString("a"), MyReader.GetString("b"), MyReader.GetString("c"), MyReader.GetString("d"));
}
MyReader.Close();
}
}
catch (Exception ex)
{
MessageBox.Show(ex.Message);
}
}
Since OpenFormNewNote is called when the "Change" event of FileSystemWatcher is triggered.. of course it runs on a separated thread. Instead Refresh() does some UI stuff and it can't be called directly from OpenFormNewNote() otherwise it gives a Cross-Thread exception. So I tried with delegate but when the codeflow arrives on the BeginInvoke part.. Nothing happens and the Refresh function is not called.
What should I do?

Notify winforms application by Sql Server database changes

I created a Sql server database, in which I added a table named user. Then I executed this script
ALTER DATABASE [TestNotification] SET ENABLE_BROKER
I'd like to use SqlDependency class to notify a winforms application when the user table were changed.
namespace Watcher
{
public partial class Form1 : Form
{
private int changeCount = 0;
private const string statusMessage = "{0} changes have occurred.";
private DataSet dataToWatch = null;
private SqlConnection connection = null;
private SqlCommand command = null;
public Form1()
{
InitializeComponent();
button1.Enabled = CanRequestNotifications();
this.FormClosed += Form1_FormClosed;
}
void Form1_FormClosed(object sender, FormClosedEventArgs e)
{
SqlDependency.Stop(GetConnectionString());
if (connection != null)
{
connection.Close();
}
}
private bool CanRequestNotifications()
{
// In order to use the callback feature of the
// SqlDependency, the application must have
// the SqlClientPermission permission.
try
{
SqlClientPermission perm =
new SqlClientPermission(
PermissionState.Unrestricted);
perm.Demand();
return true;
}
catch
{
return false;
}
}
private void button1_Click(object sender, EventArgs e)
{
changeCount = 0;
label1.Text = String.Format(statusMessage, changeCount);
//SqlDependency.Stop(GetConnectionString());
SqlDependency.Start(GetConnectionString());
if (connection == null)
{
connection = new SqlConnection(GetConnectionString());
}
if (command == null)
{
command = new SqlCommand(GetSQL(), connection);
}
if (dataToWatch == null)
{
dataToWatch = new DataSet();
}
GetData();
}
private string GetConnectionString()
{
return #"Data Source=BILOG-PRT-12\SQLEXPRESS; Initial Catalog=TestNotification;Integrated Security=True";
}
private string GetSQL()
{
return "Select [id],[nom],[prenom],[age] from [dbo].[user]";
}
private void dependency_OnChange(object sender, SqlNotificationEventArgs e)
{
MessageBox.Show("modification Occurred");
ISynchronizeInvoke i = (ISynchronizeInvoke)this;
if (i.InvokeRequired)
{
OnChangeEventHandler tempDelegate =new OnChangeEventHandler(dependency_OnChange);
object[] args = { sender, e };
i.BeginInvoke(tempDelegate, args);
return;
}
SqlDependency dependency = (SqlDependency)sender;
dependency.OnChange -= dependency_OnChange;
++changeCount;
label1.Text = String.Format(statusMessage, changeCount);
GetData();
}
private void GetData()
{
//dataToWatch.Clear();
//command.Notification = null;
SqlDependency dependency = new SqlDependency(command);
if (connection.State != ConnectionState.Open) connection.Open();
using (var dr = command.ExecuteReader())
{
dependency.OnChange += new OnChangeEventHandler(dependency_OnChange);
}
}
}
}
All the broker service are running :
I launched the application, Then I clicked into the button and finally I go the Sql Server management studio And I inserted a new row. The problem is that the message box in the application is not shown so the c# application is not notified by SQL Server!!!
So I need to know :
Why this happens?
Which step I forget ?
How can I resolve this issue?

There's quite a few limitations with SqlDependency. To quote one relevant issue:
The projected columns in the SELECT statement must be explicitly stated, and table names must be qualified with two-part names.Notice that this means that all tables referenced in the statement must be in the same database.
(see https://msdn.microsoft.com/library/ms181122.aspx for the full list)
You have to explicitly use two-part name (e.g. dbo.user instead of just user).
Also, you need to execute the command. It doesn't just start working automagically :) Adding a simple using (var dr = command.ExecuteReader()) {} should be enough.

Ping multiple IP addresses and set the timer to re-ping

I have code below to ping the IP address, but when I run this code, it's not running because there is no update into the database.
Here is the Start code:
protected void Start()
{
string ip_STCKL = "*.*.10.";
string ip_STCKCH = "*.*.128.";
for (int ipCount = ip_addr; ipCount < 195; ipCount++)
{
string ip = ip_STCKL + ipCount.ToString();
string loopIp = ip;
WaitCallback func = delegate(object state)
{
if (PingIP(loopIp))
{
UpdateStatusKL(loopIp, true);
Console.WriteLine("Ping Success");
}
else
{
loopIp = ip_STCKCH + ipCount.ToString();
if (PingIP(loopIp))
{
UpdateStatusKL(loopIp, true);
//Console.WriteLine("Ping Success");
}
else
{
UpdateStatusKL(loopIp, false);
//Console.WriteLine("Ping Failed");
}
}
};
ThreadPool.QueueUserWorkItem(func);
//ThreadPool.GetAvailableThreads;
}
//Console.ReadLine();
}
This is the ping function to get the status:
public static bool PingIP(string IP)
{
bool result = false;
try
{
Ping ping = new Ping();
PingReply pingReply = ping.Send(IP);
if (pingReply.Status == IPStatus.Success)
result = true;
}
catch(Exception)
{
result = false;
}
return result;
}
After get the status, update into the database:
public void UpdateStatusKL(string IP, bool Status)
{
string New_Status = "";
if (Status)
{
New_Status = "REACHABLE";
}
else
{
New_Status = "UNREACHABLEE";
}
//Declare the connection object
OracleConnection Conn = new OracleConnection("Data Source=COMMSERVERKL;User
Id=mt_mon;Password=butus123");
//Make the connection
Conn.Open();
//Define you query
string sql = "UPDATE BalaiConnectionStatus SET Balai_Status = :pstatus,
Timestamp = :pTime WHERE IP_STCKL = :pIP OR IP_STCKCH = :pIP";
//Declare the Command
OracleCommand cmd = new OracleCommand(sql, Conn);
//Add the parameters needed for the SQL query
cmd.CommandType = CommandType.Text;
cmd.Parameters.Add("pstatus", OracleType.VarChar).Value = New_Status;
cmd.Parameters.Add("pTime", OracleType.VarChar).Value =
DateTime.Now.ToString();
cmd.Parameters.Add("pIP", OracleType.VarChar).Value = IP;
//Execute the query
cmd.ExecuteNonQuery();
Conn.Close();
}
Every 15 minutes when the timer trigger, it will call the Start function to start pinging all the IP addresses again:
private void timer1_Tick(object sender, EventArgs e)
{
ip_addr = 10;
Start();
}
What is the problem with my code and how can I fix it?

textbox and dropdown values inserted should store in database using c# asp.net

I got a tab container which has 4 tabs in it. In one of the tab named ADD TASK I got few fields like
(Task Name: --txtbox
Client Name:--drpdwn
Begin Date:--txtbox wid calendar
Due Date:--txtbox wid calendar
Description:--txtbox
Assign To:--drpdown
Status:--drpdown
% Complete:--drpdown)
and an ADD and CANCEL button in the end.
On running the project and inserting the values to those above mentioned fields i will click the add button and after clicking the button the values should store in my DATABASE. i have table named TASK in my DB already.
Please help me with the back end code.
here is my code
protected void BtnAdd_Click(object sender, EventArgs e)
{
MTMSDTO objc = new MTMSDTO();
int Flag = 0;
objc.TaskName = Session["TaskName"].ToString();
objc.ClientName = DrpClientName.SelectedItem.Text;
objc.BeginDate = Convert.ToDateTime(TxtBeginDate.Text);
objc.DueDate = Convert.ToDateTime(TxtDueDate.Text);
objc.Description = Session["Description"].ToString();
objc.AssignTo = DrpAssignTo.SelectedItem.Text;
objc.Status = DrpStatus.SelectedItem.Text;
objc.PercentageComplete = Convert.ToInt32(DrpPercentageComplete.Text);
int X = obj.InsertTask(objc);
{
if (X >= 0)
{
Flag = 1;
}
else
{
Flag = 0;
}
}
if (Flag == 1)
{
LblSuccess.Visible = true;
LblSuccess.Text = "Data Added Successfully";
Panel2.Visible = false;
}
else
{
LblErr.Visible = true;
LblErr.Text = "Failed To Add Data!!!";
}
}
im using layered architecture and i have this code on my ACCESS file of DAL CLASS
public int InsertTask(MTMSDTO M)
{
DBAccess db = new DBAccess();
SqlParameter objParam = new SqlParameter("#TaskID", M.TaskID);
objParam.Direction = ParameterDirection.Output;
db.Parameters.Add(new SqlParameter("#TaskName", M.TaskName));
db.Parameters.Add(new SqlParameter("#ClientName", M.ClientName));
db.Parameters.Add(new SqlParameter("#BeginDate", M.BeginDate));
db.Parameters.Add(new SqlParameter("#DueDate", M.DueDate));
db.Parameters.Add(new SqlParameter("#Description", M.Description));
db.Parameters.Add(new SqlParameter("#AssignTo", M.AssignTo));
db.Parameters.Add(new SqlParameter("#Status", M.Status));
db.Parameters.Add(new SqlParameter("#PercentageComplete", M.PercentageComplete));
db.Parameters.Add(objParam);
int retval = db.ExecuteNonQuery("InsertTask");
if (retval >= 1)
{
return int.Parse(objParam.Value.ToString());
}
else
{
return -1;
}
}
the code is edited now but im getting error as "object reference not set to an instance of an object. " for the line (objc.TaskName = Session["TaskName"].ToString();) which is in BtnAdd_Cick.

Shouldn't your BtnAdd_Click function be something like this instead? You don't currently seem to be calling the InsertTask() function.
protected void BtnAdd_Click(object sender, EventArgs e) {
MTMSDTO m = new MTMSDTO();
m.TaskName = TxtTaskName.Text;
m.ClientName = DrpClientName.Text;
m.BeginDate = TxtBeginDate.Text;
m.DueDate = TxtDueDate.Text;
m.Description = TxtDescription.Text;
m.AssignTo = DrpAssignTo.Text;
m.Status = DrpStatus.Text;
m.PercentageComplete = DrpPercentageComplete.Text;
InsertTask(m);
}

get all values in back end and pass to this function
public bool InsertRecord(string strTableName, string strColumn_Name, string strValues)
{
SqlConnection OBJCONNECTION;
StringBuilder strbQuery;
SqlCommand cmd;
try
{
OBJCONNECTION= new SqlConnection();
OBJCONNECTION.ConnectionString = ConfigurationManager.ConnectionStrings["Basic_ADO"].ConnectionString;//get connection string from web.config file
OBJCONNECTION=
strbQuery = new StringBuilder();
strbQuery.Append("INSERT INTO ");
strbQuery.Append(strTableName);
strbQuery.Append("(" + strColumn_Name + ")");
//strbQuery.Append(" VALUES");
strbQuery.Append("(" + strValues + ")");
cmd = new SqlCommand(strbQuery.ToString(), OBJCONNECTION);
cmd.ExecuteNonQuery();
return true;
}
catch (Exception ex) { throw ex; }
finally { strbQuery = null; cmd = null;OBJCONNECTION.close();}
}