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Hi - I am trying to send a simple string over an established Bluetooth connection using serial port. The probelm here is I don't know if what I am doing is correct as neither application are throwing any exceptions. Here is the code for the remote application
private void btnConnect_Click(object sender, EventArgs e)
{
try
{
SerialPort inPort = new SerialPort("COM2", 9600);
inPort.Open();
string message = "Hello";
inPort.Write(message);
inPort.Close();
}
catch (Exception ex)
{
MessageBox.Show(ex.Message);
}
}
On the other end I have used an event handler:
private void DataReceviedHandler(object sender, SerialDataReceivedEventArgs e)
{
try
{
SerialPort inPort = new SerialPort("COM7", 9600);
inPort.Open();
string mess = inPort.ReadLine();
MessageBox.Show("This worked...");
inPort.Close();
}
catch (Exception ex)
{
MessageBox.Show(ex.Message);
}
}
}
}
When I click on the button on the external application nothing happens? Any ideas????
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There could be dozens of things wrong, getting a serial communication up and running requires all of them being right. Here are some suggestions:
- start by checking your physical connection by the simplest means, e.g. one party is constantly sending text (say one line every second), the other party uses HyperTerminal to receive them. Now experiment with cables, connectors, port settings, until characters are coming in.
- only when that works is it worthwhile expanding the software.
One immediate hint: ReadLine waits for a line of text, i.e. some characters ending on SerialPort.NewLine (which defaults to CR or LF or both, I can't remember). Your Write isn't sending any of them, try WriteLine.
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private void DataReceviedHandler(object sender, SerialDataReceivedEventArgs e)
{
try
{
SerialPort inPort = new SerialPort("COM7", 9600);
inPort.Open();
string mess = inPort.ReadLine();
MessageBox.Show("This worked...");
inPort.Close();
}
catch (Exception ex)
{
MessageBox.Show(ex.Message);
}
}
in the above handler comport should be open previously, the receive comport should be open before sending the data by the sender comport.,
And also problem may be the comport settings as said in the above answer.., check all the comport settings are correct before starting your serialport communication.
Rajesh B --> A Poor Workman Blames His Tools <--
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After alot of hair pulling and banging my head on the wall, finally figured out why by code isn't working. First of all, there are 4 serial ports available on my PC. The fact that I am trying to use the same serial port to test my Windows mobile application and send data over the same serial port explains why. So one would then suggest trying to use another port, well there is two problems with this; first active sync lunches and takes this spare serial port(have tried killing the process, this didn't help), Secondly also discovered that my Windows mobile device only supports on connection at a time so hence while I am testing it I can not open another port, which really sucks... So now I am diching using bluetooth all together and am using WiFi. I know what your thinking (won't I run into the same problems as with bluetooth), well with WiFi I am going to create a dummy application (desktop) that will sent strings, if this works I will then rebuild it as a Windows Mobile application, hopefully it should work...Thanks for the help everyone...
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So in an effort to better learn C#, I'm taking a Java program used in one of my old classes and converting it. For the most part I've gotten things figured out, however the generics are throwing me for a loop as they aren't quite the same as Java.
I have a custom List class declared as follows:
public class List<A>
I also have a Function interface which is:
interface Function<A,B>
{
B f(A o);
}
Inside the List class I try the following and I get an error on the 'B' type, it's complaining that the namespace B could not be found. This sort of thing works fine in Java, I'm trying to figure out the comparable way to do it in C#.
public List<A> map (Function<A,B> fun)
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That's because you used B as a generic type parameter but B does not exist.
If you change map to map<B> it should work (and with some luck you won't even need to make B explicit in invocations of map, if the compiler can figure out the type for you)
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Thanks, that took care of it for me.
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Say, I have a resource file Res.resx with strings predefined. Then I create a new form using designer. Is it possible to use the string resources from the designer view to assign the properties, like text, so the line in the designer file would look like:
this.Text = global::My.Namespace.Res.Localized_text; ?
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I have seen most of sniffering application sniffs network traffic according to IP address or NIC cards. But I want to sniff at application level. Real example can be an Anti-virus Application. It can sniff and block requests at application level.
So how can I do something like that ? Any example or guidance ?
Or
Is there any way to find out which application sent a given request ?
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Hi,
I am using c# and sql for this simple example and I have two related tables: Master, Details. The Primary Key in Master is MasterId and there is a Foreign Key in Details table to establish the relation. The columns of Master are bound to textbox while the Details table are bound to datagridview. MasterBindingSource and DetailBindingSource are generated automatically. My problem with this is that adding a new Master along with its Details, coz it errors with FK constraint violated. Actually, when I add a new Master, the MasterId value @ the textbox is -1, so the value that was recognized by the Details MasterId @ the datagridview is -1 likewise, so when the insertion is updated to the database, MasterId is automatically set by the db engine due to its identity property. However, this MasterId is not known to the dataset. So when the Details table is updated to the database, the error occurs(Sql Exception was unhandled). So I need help for this problem coz I tried everything but nothing happened.
Anyway, here is my simple code as shown:
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
using System.Data.SqlClient;
namespace MasterDetail
{
public partial class Form1 : Form
{
//DsMasterDetail ds = new DsMasterDetail();
public Form1()
{
InitializeComponent();
}
private void Form1_Load(object sender, EventArgs e)
{
this.masterTableAdapter.Fill(this.dsMasterDetail.Master);
this.detailTableAdapter.Fill(this.dsMasterDetail.Detail);
}
void Master_RowChanged(object sender, DataRowChangeEventArgs args)
{
}
private void masterBindingNavigatorSaveItem_Click(object sender, EventArgs e)
{
Validate();
masterBindingSource.EndEdit();
masterTableAdapter.Update(this.dsMasterDetail.Master);
dgvDetail.Refresh();
detailBindingSource.EndEdit();
detailTableAdapter.Update(this.dsMasterDetail.Detail);
}
private void dgvDetail_DefaultValuesNeeded(object sender, DataGridViewRowEventArgs e)
{
//e.Row.Cells[1].Value = bnPositionItem.Text;
}
}
}
Thanks in advance, your help will be greatly appreciated.
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I think instead of using masterTableAdapter.Update(this.dsMasterDetail.Master);
you can use sql query to insert new data.
rahul
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Hi Rahul,
Anyway, tnx for the reply. So I will redesign my code using a query instead of using MasterTableAdapter. I will send you feedback later if there's still a problem.
Thanks again.
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Hi,
I think i found the best solution using this code below:
void save()
{
Validate();
// Disable constraints
ds.EnforceConstraints = false;
DsMasterDetail.MasterRow master = (DsMasterDetail.MasterRow)(((DataRowView)masterBindingSource.Current).Row);
DsMasterDetail.DetailRow detail = (DsMasterDetail.DetailRow)(((DataRowView)detailBindingSource.Current).Row);
masterBindingSource.EndEdit();
masterTableAdapter.Update(master);
detail.MasterId = master.MasterId;
detailBindingSource.EndEdit();
detailTableAdapter.Update(detail);
//Re-enable constraints
ds.EnforceConstraints = true;
}
This code solves my problem with Fk_Constraint. Actually it is working only for single data entry at details data table, but the only problem is that when adding a new Master at the textbox along with multiple details at the datagridview at the same time, coz it only fires up the last record of the datagrid and bypasses the corresponding rows. I need help for this problem.
Thanks.
Hardz
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Redesign and don't use a Grid.
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Hi,
Anyway, I am using a datagridview for data entry coz for every Master there's a corresponding multiple details, so the reason for using a datagridview is to enter many details.
Tnx for the reply..
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You'll be better of designing a form or a series of forms for entering the data. And your users will probably prefer it.
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Hi,
Tnx for the reply and suggestions that helps me a lot.
Anyway, i created a solution that solves for my problem in master/detail relationship, but not really the best one. so here is the revised code as shown below:
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
using System.Data.SqlClient;
namespace MasterChild
{
public partial class Form1 : Form
{
bool addIndicator = false;
DataSet ds = new DataSet();
int lastNoOfMasterId;
public Form1()
{
InitializeComponent();
}
private void Form1_Load(object sender, EventArgs e)
{
this.masterTableAdapter.Fill(this.dsMaster.Master);
detailLoadValue();
lastno();
}
void lastno()
{
bnMoveLastItem.PerformClick();
lastNoOfMasterId = int.Parse(txtMasterId.Text);
}
void detailLoad()
{
try
{
this.detailTableAdapter.Fill(this.dsDetail.Detail, new System.Nullable<int>(((int)(System.Convert.ChangeType(lblMasterId.Text, typeof(int))))));
}
catch (System.Exception ex)
{
System.Windows.Forms.MessageBox.Show(ex.Message);
}
}
void detailLoadValue()
{
lblMasterId.Text = txtMasterId.Text;
detailLoad();
}
private void bindingNavigatorMoveNextItem_Click(object sender, EventArgs e)
{
detailLoadValue();
}
private void bindingNavigatorMoveLastItem_Click(object sender, EventArgs e)
{
detailLoadValue();
}
private void bindingNavigatorMovePreviousItem_Click(object sender, EventArgs e)
{
detailLoadValue();
}
private void bindingNavigatorMoveFirstItem_Click(object sender, EventArgs e)
{
detailLoadValue();
}
private void masterBindingNavigatorSaveItem_Click(object sender, EventArgs e)
{
this.Validate();
ds.EnforceConstraints = false;
this.masterBindingSource.EndEdit();
this.masterTableAdapter.Update(this.dsMaster.Master);
this.detailBindingSource.EndEdit();
this.detailTableAdapter.Update(this.dsDetail.Detail);
ds.EnforceConstraints = true;
addIndicator = false;
}
private void bindingNavigatorAddNewItem_Click(object sender, EventArgs e)
{
if (addIndicator)
{
return;
}
else
{
detailLoadValue();
lastNoOfMasterId += 1;
addIndicator = true;
}
}
private void dgvDetail_RowEnter(object sender, DataGridViewCellEventArgs e)
{
if (addIndicator)
{
lblMasterId.Text = lastNoOfMasterId.ToString();
}
else
{
lblMasterId.Text = txtMasterId.Text;
}
}
}
}
So using the integer lastNoOfMasterId that detects the last number of MasterId and automatically incremented if the user press an add button, which is now a value of MasterId at Details datagrid, replacing the -1 default value during add. With this i am not having trouble now on null value of MasterId at details table and adding a new master along with its details is no longer a problem to me.
But i think this kind of code is much more complicated. Is there any simplified one aside from this?
tnx again for the suggestions.
Har
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Greetings !
I am new to programming, iwant your help to creat an rss reader in C# using visual studio 2010.
thaks
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You have posted a similar question in the .Net framework forums as well.
The funniest thing about this particular signature is that by the time you realise it doesn't say anything it's too late to stop reading it.
My latest tip/trick
Visit the Hindi forum here.
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Abhinav S wrote: You have posted a similar question in the .Net framework forums as well.
Perhaps he's writing two applications, one using C# and one in a different CLI language (perhaps F#) and wants to compare and contrast the differences in approach and thinking. Or maybe he's just cross posting!
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Errrmmmmmmm I call Occam's razor 
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This[^] article may help get you started.
/ravi
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Hi guys,
I'm using the following code to restore a backup sql database with C# and SMO.
void RestoreDatabaseWithSMO(string sConnect, string dbName, string backUpPath)
{
using (SqlConnection cnn = new SqlConnection(sConnect))
{
cnn.Open();
cnn.ChangeDatabase("master");
ServerConnection sc = new ServerConnection(cnn);
Server sv = new Server(sc);
if (!sv.Databases.Contains(dbName))
throw new Exception("this DataBase does not exist");
BackupDeviceItem bdi = new BackupDeviceItem(backUpPath, DeviceType.File);
Restore resDB = new Restore();
resDB.PercentComplete += new PercentCompleteEventHandler(percentComplete);
resDB.PercentCompleteNotification = 10;
resDB.Devices.Add(bdi);
resDB.NoRecovery = false;
resDB.ReplaceDatabase = true;
resDB.Database = dbName;
resDB.Action = RestoreActionType.Database;
resDB.SqlRestore(sv);
}
}
but in the last line I got below exception !!!
{"Restore failed for Server '\\\\.\\pipe\\3F103E6E-3FD4-47\\tsql\\query'. "}
What's wrong with it ?
Could you please guide me?
Thanks
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Hello everyone
I've generated an SQL statement in my .cs file as
cmd.Connection = conn //this is working, worked before in the same code
cmd.CommandText = "INSERT INTO <table> VALUES ('value1','value2')";
conn.Open
cmd.ExecuteNonQuery
conn.Close
the problem is:
I'm checking the SQL statement in debug, copying the same query on my MySQL QueryBrowser and executing
the same string works in the querybrowser, but in ExecuteNonQuery() doesn't
what can be the problem?
notes:
1-connection is done, checked, and double checked, a few lines earlier, several SELECT statements are
executed and worked
2-connection string is not changed before this code, it was the same before
3-I'm not changing the code while copying to the Querybrowser, taking the text as it is directly from
debug window and pasting it to the SQL browser tool.
any ideas?
<div class="modified">modified on Tuesday, October 19, 2010 2:39 PM</div>
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