|
You might want to consider web services if you want to set up a communication channel between two web sites.
My signature "sucks" today
|
|
|
|
|
Hello CPers,
I'm trying to get a Winform to do some stuff while a button is pressed down, and stop doing it when the button's let go. I'm trying this out in a simple form with a button and a label. So as long as the button is pressed (MouseDown) the value displayed on the label should keep incrementing by 1. I've tried to used a BackgroundWorker for this and have so far failed. So, in my form class I have:
BackgroundWorker bwAsync = new BackgroundWorker();
public Form1() {
InitializeComponent();
bwAsync.WorkerReportsProgress = true;
bwAsync.WorkerSupportsCancellation = true;
bwAsync.DoWork += new DoWorkEventHandler(bwAsync_DoWork);
}
private void button1_MouseDown(object sender, MouseEventArgs e) {
bwAsync.RunWorkerAsync();
}
private void button1_MouseUp(object sender, MouseEventArgs e) {
bwAsync.CancelAsync();
}
void bwAsync_DoWork(object sender, DoWorkEventArgs e) {
BackgroundWorker bwAsync = sender as BackgroundWorker;
int i;
label1.Invoke( (MethodInvoker)delegate()
{
i = int.TryParse(label1.Text, out i) ? i : 0;
while(!bwAsync.CancellationPending){
Console.WriteLine("down");
label1.Text = i.ToString();
i++;
}
});
}
What happens here is, once it goes into DoWork() it gets stuck in the loop, and it never gets to the MouseUp handler. Anyone have any feeback on my code, or on how it's supposed to be done? Would be much appreciated.
Thank you.
modified on Sunday, June 13, 2010 11:47 PM
|
|
|
|
|
Hi,
your label1.Invoke causes the entire while loop to execute on the main thread (so it is allowed to touch the Label), however that also blocks the thread, so your button1_MouseUp handler cannot react to the button being released. (The main thread processes its event queue, popping and executing one message at a time).
Furthermore, your while loop does not contain any timing control (such as a Thread.Sleep), so it will spin as fast as it can (depending on the characteristics and the load of your system), and clogging your Console.
I would use a very different approach, without BGW:
- have a class member of type System.Windows.Forms.Timer;
- have a class member "int tickCount";
- in button1_MouseDown clear tickCount and launch that timer, with an appropriate interval (say 100 msec), and a tick handler basically containing:
Console.WriteLine("down");
tickCount++;
label1.Text=tickCount.ToString();
- in button1_MouseUp simply stop the timer.
The advantages would be: code is much simpler, everything runs on the main thread, which is idle most of the time, as all it does is run one tick handler every 100 msec.
|
|
|
|
|
THAT was ridiculously easy and clean. To think I spent the better part of the day trying to manipulate threads.. 
Thanks, Luc!
|
|
|
|
|
No problem.
Yes one tends to find convoluted ways first.
BTW: You may want to switch to a BGW as soon as some real work needs to be done. Then the calculations would go into the DoWork handler (without Invoke!) and hence really run on the BGW thread, however reporting progress or intermediate results to the GUI would best be handled by calling ReportProgress(), which causes the ProgressChanged handler to run on the main thread automatically.
|
|
|
|
|
Your suggestions are much appreciated. Will do
|
|
|
|
|
when u have this message Syntax error in UPDATE statement.how can slove it
|
|
|
|
|
aaga5 wrote: when u have this message Syntax error in UPDATE statement.how can slove it
by fixing the syntax of your UPDATE statement.
if you want more details, maybe you should provide more details.
|
|
|
|
|
aaga5 wrote: Syntax error in UPDATE statement.how can slove it
You can read a documentation of the UPDATE statement here[^]. Stick to the syntax described there and everything should be OK. If not, please tell us what was the query.
Greetings - Jacek
|
|
|
|
|
This is the C# forum.
My signature "sucks" today
|
|
|
|
|
Hi
I'm trying to use the name of a logical drive (c: and d . I can't use them to get access to the physical drive in order to get the type, the model, the interface, the capacity, sectors and cylinders.
My code :
private void Form1_Load(object sender, EventArgs e)
{
ManagementObjectSearcher mosDisks = new ManagementObjectSearcher("SELECT * FROM Win32_LogicalDisk");
foreach (ManagementObject moDisk in mosDisks.Get())
{
comboBox2.Items.Add(moDisk["DeviceID"].ToString());
}
}
private void button4_Click_1(object sender, EventArgs e)
{
listView2.Items.Clear()
ManagementObjectSearcher mosDisks = new ManagementObjectSearcher("SELECT * FROM Win32_DiskDrive WHERE DeviceID = '" + comboBox2.SelectedItem + "'");
foreach (ManagementObject moDisk in mosDisks.Get())
{
ListViewItem item = listView2.Items.Add("Type: " + moDisk["MediaType"].ToString());
ListViewItem item2 = listView2.Items.Add("Model: " + moDisk["Model"].ToString());
ListViewItem item3 = listView2.Items.Add("Interface: " + moDisk["InterfaceType"].ToString());
ListViewItem item4 = listView2.Items.Add("Capacity: " + moDisk["Size"].ToString() + " bytes (" + Math.Round(((((double)Convert.ToDouble(moDisk["Size"]) / 1024) / 1024) / 1024), 2) + " GB)");
ListViewItem item5 = listView2.Items.Add("Partitions: " + moDisk["Partitions"].ToString());
ListViewItem item6 = listView2.Items.Add("Signature: " + moDisk["Signature"].ToString());
ListViewItem item7 = listView2.Items.Add("Cylinders: " + moDisk["TotalCylinders"].ToString());
ListViewItem item8 = listView2.Items.Add("Sectors: " + moDisk["TotalSectors"].ToString());
ListViewItem item9 = listView2.Items.Add("Heads: " + moDisk["TotalHeads"].ToString());
ListViewItem item10 = listView2.Items.Add("Tracks: " + moDisk["TotalTracks"].ToString());
ListViewItem item11 = listView2.Items.Add("Bytes per Sector: " + moDisk["BytesPerSector"].ToString());
ListViewItem item12 = listView2.Items.Add("Sectors per Track: " + moDisk["SectorsPerTrack"].ToString());
ListViewItem item13 = listView2.Items.Add("Tracks per Cylinder: " + moDisk["TracksPerCylinder"].ToString());
ListViewItem item14 = listView2.Items.Add("Description: " + moDisk["Description"].ToString());
}
}
I have used this code and it worked fine but I can't get the letters instead of the Model in the combox
private void Form1_Load(object sender, EventArgs e)
{
ManagementObjectSearcher mosDisks = new ManagementObjectSearcher("SELECT * FROM Win32_DiskDrive");
foreach (ManagementObject moDisk in mosDisks.Get())
{
comboBox2.Items.Add(moDisk["Model"].ToString());
}
}
private void button4_Click_1(object sender, EventArgs e)
{
listView2.Items.Clear();
ManagementObjectSearcher mosDisks = new ManagementObjectSearcher("SELECT * FROM Win32_DiskDrive WHERE Model = '" + comboBox2.SelectedItem + "'");
foreach (ManagementObject moDisk in mosDisks.Get())
{
ListViewItem item = listView2.Items.Add("Type: " + moDisk["MediaType"].ToString());
ListViewItem item2 = listView2.Items.Add("Model: " + moDisk["Model"].ToString());
ListViewItem item3 = listView2.Items.Add("Interface: " + moDisk["InterfaceType"].ToString());
ListViewItem item4 = listView2.Items.Add("Capacity: " + moDisk["Size"].ToString() + " bytes (" + Math.Round(((((double)Convert.ToDouble(moDisk["Size"]) / 1024) / 1024) / 1024), 2) + " GB)");
ListViewItem item5 = listView2.Items.Add("Partitions: " + moDisk["Partitions"].ToString());
ListViewItem item6 = listView2.Items.Add("Signature: " + moDisk["Signature"].ToString());
ListViewItem item7 = listView2.Items.Add("Cylinders: " + moDisk["TotalCylinders"].ToString());
ListViewItem item8 = listView2.Items.Add("Sectors: " + moDisk["TotalSectors"].ToString());
ListViewItem item9 = listView2.Items.Add("Heads: " + moDisk["TotalHeads"].ToString());
ListViewItem item10 = listView2.Items.Add("Tracks: " + moDisk["TotalTracks"].ToString());
ListViewItem item11 = listView2.Items.Add("Bytes per Sector: " + moDisk["BytesPerSector"].ToString());
ListViewItem item12 = listView2.Items.Add("Sectors per Track: " + moDisk["SectorsPerTrack"].ToString());
ListViewItem item13 = listView2.Items.Add("Tracks per Cylinder: " + moDisk["TracksPerCylinder"].ToString());
ListViewItem item14 = listView2.Items.Add("Description: " + moDisk["Description"].ToString());
}
}
|
|
|
|
|
I am not sure that you can get the drive letters using the PhysicalDrive. Look up Win32_MappedLogicalDisk in the WMI documentation. From memory it is much easier to get the drive letters that way.
Henry Minute
Do not read medical books! You could die of a misprint. - Mark Twain
Girl: (staring) "Why do you need an icy cucumber?"
“I want to report a fraud. The government is lying to us all.”
Why do programmers often confuse Halloween and Christmas? - Because 31 Oct = 25 Dec.
Business Myths of the Geek #4 'What you think matters.'
|
|
|
|
|
The logical drives (drive letters) identify partitions, not physical devices. It takes a couple of WMI objects to get most of the information you want; you will probably discover that the very physical characteristics (such as number of cylinders) don't make sense any more as they are virtualized within the drive itself; the local intelligence just makes the disk look like one heap of sectors.
Also, the latest versions of Windows (Vista, 7) are likely to refuse full access, even read access, at the device level unless you are an elevated escalated super-administrator.
|
|
|
|
|
connectionString1 = @"
server = .\sqlexpress;
integrated security = true;
database = C:\Program Files\Microsoft SQL Server\MSSQL10.SQLEXPRESS\MSSQL\DATA\NORTHWND.MDF;
user instance = true";
connectionString2 = @"
server = .\sqlexpress;
integrated security = true;
database = northwind";
connectionString1 is working fine and connectionString2 is giving the message "Cannot open database northiwnd. login failed for user XYZ".
Can someone tell me whats the difference
|
|
|
|
|
humayunlalzad wrote: atabase = C:\Program Files\Microsoft SQL Server\MSSQL10.SQLEXPRESS\MSSQL\DATA\NORTHWND.MDF;user instance = true";
humayunlalzad wrote: database = northwind";
The difference lies in the user instance = true part of the sql.
Read about user instances here.
My signature "sucks" today
|
|
|
|
|
@"
server = .\sqlexpress;
integrated security = true;
database = northwind;
user instance = true";
I am sorry I should have mentioned before hand, that even the above string with "user instance = true" added is not working
|
|
|
|
|
hi all
i have an win application form suppose to show some reports in CrystalReportView i have no idea how to assign a list<> of class to MyCrystalReport
public Form1()
{
InitializeComponent();
StdList = new List<studants>();
StdList.Add(new studants("1", "1", 1));
StdList.Add(new studants("2", "2", 2));
StdList.Add(new studants("3", "3", 3));
StdList.Add(new studants("4", "4", 4));
StdList.Add(new studants("5", "5", 5));
}
private void Form1_Load(object sender, EventArgs e)
{
CrystalReport1 cr = new CrystalReport1();
cr.SetDataSource(StdList);
crystalReportViewer1.ReportSource = cr;
}
but i have not assigned any table with CrystalReport1 it`s all because of i have not any dataset or database or ... and i do not know how to assign add or assign a list<> of objects to my crytalReport Project (CrystalReport1) how can i assign it and work on it
i should definitely use list<>
please help me!!!!!!!!!!
|
|
|
|
|
Does CR support List<> as a datasource? I have not used that POS in a few years but I doubt it has moved that fast.
I suggest you do some research on the Business Object web site.
Never underestimate the power of human stupidity
RAH
|
|
|
|
|
I have a label called lblsite that I'm trying to give a value from a cached value.
protected void Page_Load(object sender, System.EventArgs e)<br />
{<br />
lblsite.Text = (Cache("locid") + 1);<br />
}
The "locid" is set on the previous page.
protected void btnaddaddress_Click(object sender, System.EventArgs e)<br />
{<br />
Cache["locid"] = gvaddressmax.SelectedRow.Cells[0].Text;<br />
Response.Redirect("btnaddaddress.aspx");<br />
}
However, the lblsite.Text = (Cache("locid") + 1); gives me the following error and results in a null value.
'System.Web.Caching.Cache' is a Type, but being used like a variable
How can I get this to work?
|
|
|
|
|
You should have posted in the asp forum. Anyway, I think it's the parenthesis.
try (Cache)("locid") +1;
even better
(yourType)((Cache)("locid")) +1;
You did not mentioned what you stored in the previous page.
Just an irritated, ranting son of ... an IT guy.
At your trolling services
|
|
|
|
|
Randall Hall wrote: (Cache("locid") + 1)
This is the problem. Cache provides indexer access to object values, so you need to extract the value back out before you attempt to work with it. Try changing this instead to:
int value;
if (int.TryParse(Cache["locid"], out value))
{
lblsite.Text = ++value;
}
"WPF has many lovers. It's a veritable porn star!" - Josh Smith As Braveheart once said, "You can take our freedom but you'll never take our Hobnobs!" - Martin Hughes.
My blog | My articles | MoXAML PowerToys | Onyx
|
|
|
|
|
Hi,
I'm interested in adding a small exit button to the top part of the active Tab Page (like the one in the IE's Tabs), in order to enable users to close tabs more easily.
I'd appreciate any info on how to acomplish this (probably involves owner drawn tab control + more), or if anyone has already implemented such Tab Contol/Tab Page - a link to it...
tnx
roy
|
|
|
|
|
I assume Winforms so here is one of the many results here on CP:
link1
Search is the key
Just an irritated, ranting son of ... an IT guy.
At your trolling services
|
|
|
|
|
Exactly what i was looking 4..
Tnx
Roy
|
|
|
|
|
If its web you may look forward to coolite [^]toolkit.
|
|
|
|
General 
News 
Suggestion 
Question 
Bug 
Answer 
Joke 
Praise 
Rant 
Admin 
Submit an article or tip
