Re: Threading - C# Discussion Boards

Calla9-Feb-10 23:52

9-Feb-10 23:52

Yes, a Windows (NT) Service is the way to go here. There are plenty of articles on how to create one so google will provide you with many of relevant answers on this matter. Good luck! Smile | :)

Re: process in c#

PIEBALDconsult10-Feb-10 3:26

PIEBALDconsult

10-Feb-10 3:26

A Windows Scheduled Task might do it as well.

Split Data Table Records into several parts and assign to different Threads

prabhakar CSPL9-Feb-10 22:47

prabhakar CSPL

9-Feb-10 22:47

Hi,
I would like to use Multi threading to improve the performance. I have a datatable it may have any no of records. But the problems is i have to split those records and assign some records to one thread, some other records to other thread and so on.
I will pass the table,no of threads, records for thread like the following

public void MultiThreadingSample(DataTable table, int noOfThreads,int recordsForThread)
{

}
please help to me.

Threading

MumbleB9-Feb-10 22:20

MumbleB

9-Feb-10 22:20

Hi Guys. I have a slight problem. I have written an app that processes various types of files. I create a Thread for each type of file being processed depending on a checkbox being checked.

Now, from each file processed I output totals to a label on the form. However, this only seems to work for the first two files being processed and the remainder does not get their totals output to the labels. Is this a known issue and is there a way I can get around this? The code is kinda long so don't really want to add any here now. But the process flow of the program is such.

1) User selects a searches for file to process.
2) User checks the appropriate checkbox.
3) Thread is started calling the block of code to run.
4) Once file is processed finalize by calling GC.Collect().

if user wants to process another file he unchecks the current chechbox, checks a new checkbox and searches for new file and above process is followed calling the appropriate Thread to run.

Can somebody advise why when running more than two "Thread" processes in succession results in the third and fourth not outputting totals to the Label's?

Excellence is doing ordinary things extraordinarily well.

Re: Threading

OriginalGriff9-Feb-10 22:31

OriginalGriff

9-Feb-10 22:31

Without some idea of the code it is really difficult to suggest anything, but there general things you can check:
Are the thread running at all? Add some logging to a file to record what is being done, and in what order.
Are the output overwriting each other? Try logging the outputs as well.
Are the thread having problems with conflicts? Are there any locks which might be waiting?
Is it always the same threads that don't run? Or does that change depending on what order they are started in, say?

Sorry not to give concrete answers, but there is a heck of a lot that could be going wrong here - I think your first call is to gather more info!

If Barbie is so popular, why do you have to buy her friends?

Eagles may soar, but weasels don't get sucked into jet engines.

If at first you don't succeed, destroy all evidence that you tried.

Re: Threading

MumbleB9-Feb-10 22:43

MumbleB

9-Feb-10 22:43

Hi Griff. The Threads are all running. Output is created from all the Threads. However, I display some totals on screen for the user to verify against. It will output the totals for two of the threads run after each other, but when running the third and fourth thread I get no totals output to screen. I have tested by adding the totals to a messagebox after it is supposed to be output to the label and that works.

Below is the code. It might be long but this is what I have.

#region Set Text Code

 public delegate void SetText(Control ctrl, string str);
 public delegate void SetLabel(Control lblctrl, string filename);
 private delegate void updateBar();

 private void setText(Control ctrl, string str)
 {
     if (this.WindowState == FormWindowState.Minimized)
         return;
     if (ctrl.InvokeRequired)
         ctrl.BeginInvoke(new SetText(setText), new object[] { ctrl, str });
     else
         ctrl.Text = str;
 }

 private void setFilename(Control lblctrl, string filename)
 {
     if (this.WindowState == FormWindowState.Minimized)
         return;
     if (lblctrl.InvokeRequired)
         lblctrl.BeginInvoke(new SetLabel(setFilename), new object[] { lblctrl, filename });
     else
         lblctrl.Text = filename;
 }

 private void finalizeProcess()
 {
     //progressBar1.Style = ProgressBarStyle.Blocks;
     //progressBar1.Value = 0;
     //progressBar1.Dispose();
     GC.Collect();
     //base.Close();
 }

 #endregion

 #region Open File Dialog Code

 private void button3_Click(object sender, EventArgs e)
 {
     if (openFileDialog1.ShowDialog() != DialogResult.OK)
     {
         return;
     }
     else
     {
         txtboxSelectFile.Text = openFileDialog1.FileName;
     }

 }

 #endregion

 #region Select File Code

 private void btnStart_Click(object sender, EventArgs e)
 {
     setText(this, "Checking Process Selection");
     if (chkboxHolders.CheckState == CheckState.Unchecked && chkboxCert.CheckState == CheckState.Unchecked &&
         chkboxPiadd.CheckState == CheckState.Unchecked && chkboxDivRecords.CheckState == CheckState.Unchecked)
     {
         MessageBox.Show("Please make a valid processing selection", "Invalid Process Selection",
             MessageBoxButtons.OK, MessageBoxIcon.Error);
     }
     else
     {
         if (chkboxHolders.Checked)
         {
             setText(this, "Holder File Processing Selected");
             processHolders();
         }
         if (chkboxCert.Checked)
         {
             setText(this, "Certificate File Processing Selected");
             processCerts();
         }

         if (chkboxPiadd.Checked)
         {
             setText(this, "Payment Instruction File Processing Selected");
             processDiv();
         }

         if (chkboxDivRecords.Checked)
         {
             setText(this, "Create Dividend Files");
             processDividends();
         }

     }
 }

 #endregion

 #region All Threading Code

 private void processHolders()
 {
     if (saveFileDialog1.ShowDialog() == DialogResult.OK)
     {
         ThreadStart starthld = new ThreadStart(convertHolders);
         Thread threadhld = new Thread(starthld);
         threadhld.Start();
     }
 }

 private void processCerts()
 {
     if (saveFileDialog1.ShowDialog() == DialogResult.OK)
     {
         ThreadStart startcert = new ThreadStart(convertCert);
         Thread threadcert = new Thread(startcert);
         threadcert.Start();
     }
 }

 private void processDiv()
 {
     if (saveFileDialog1.ShowDialog() == DialogResult.OK)
     {
         ThreadStart startdiv = new ThreadStart(convertDiv);
         Thread threaddiv = new Thread(startdiv);
         threaddiv.Start();
     }
 }

 private void processDividends()
 {
     if (folderBrowserDialog1.ShowDialog() == DialogResult.OK)
     {
         ThreadStart startdivs = new ThreadStart(convertDividendPayments);
         Thread threaddivs = new Thread(startdivs);
         threaddivs.Start();
     }
 }

 #endregion

 #region All Processing Code

 private void convertHolders()
 {
     //Declare Input File
     string infile;
     //Point to Input File
     infile = txtboxSelectFile.Text;
     //Declare output File
     string outfile;
     //Point to Output File
     outfile = saveFileDialog1.FileName;
     //Declare Lines of data
     string holdline;
     //Declare File Reader
     StreamReader sr = new StreamReader(infile);
     //Declare File Writer
     StreamWriter sw = new StreamWriter(outfile);

     //Sets the Control text
     setText(this, "Start Holder File Conversion");
     //Declare counter for number of holders on File
     int holdercount = 0;
     //Declare running Share Total
     Int64 currentbal = 0;
     //Declare running Old Balance Total
     Int64 oldbal = 0;
     //Declare Final Share Total
     long ShareTotal = 0;
     //Declare Final Old balance Total
     long ShareOld = 0;
     //Start Reading the Data
     while (!sr.EndOfStream)
     {
         holdline = sr.ReadLine();
         //Declare all Field variables
         string HID = holdline.Substring(0, 10);
         string Title = holdline.Substring(10, 45).Trim();
         string Surname = holdline.Substring(55, 100).Trim();
         string FirstName = holdline.Substring(155, 100).Trim();
         string OtherNames = holdline.Substring(255, 100).TrimEnd();
         string Gender = holdline.Substring(355, 1);
         string Addr1 = holdline.Substring(356, 35).TrimEnd();
         string Addr2 = holdline.Substring(396, 35).TrimEnd();
         string Addr3 = holdline.Substring(436, 35).TrimEnd();
         string Addr4 = holdline.Substring(476, 35).TrimEnd();
         string Addr5 = holdline.Substring(516, 35).TrimEnd();
         string PostCode = holdline.Substring(556, 10).TrimEnd();
         string Nationality = holdline.Substring(566, 25).TrimEnd();
         string BranchCode = holdline.Substring(591, 6);
         string AccountNumber = holdline.Substring(597, 16);
         string AccountType = holdline.Substring(613, 2);
         string NationalId = holdline.Substring(615, 16).TrimEnd();
         string TotalShares = holdline.Substring(631, 18);
         string FullName = Title + " " + FirstName + " " + Surname;
         int namelen = FullName.Length;
         int namerem = namelen - 35;
         currentbal = Convert.ToInt64(TotalShares);
         string OldBalance = holdline.Substring(649, 18);
         oldbal = Convert.ToInt64(OldBalance);
         ///Check for any holders that have a zero balance as these will
         ///not go onto the System unless dividend Data is Migrated.
             setText(this, "Processing HolderID: " + HID);
             if(namelen > 35)
             {
                 sw.Write(" ".PadRight(5, ' ') + "NAADD" + " ".PadRight(7, ' ') + "C" + HID +
                     FullName.Substring(0, 35).PadRight(35, ' ') + FullName.Substring(35, namerem).PadRight(35, ' ') +
                     Addr1.PadRight(35, ' ') + Addr2.PadRight(35, ' ') + Addr3.PadRight(35, ' ') + Addr4.PadRight(35, ' ') +
                     Addr5.PadRight(35, ' ') + " ".PadRight(35, ' ') + PostCode.PadRight(5, ' ') + "ZAF" +
                     "IND" + " ".PadRight(57, ' ') + HID.PadRight(12, ' ') + " ".PadRight(13, ' '));
             }
             else if (namelen <= 35)
             {
                 sw.Write(" ".PadRight(5, ' ') + "NAADD" + " ".PadRight(7, ' ') + "C" + HID + FullName.Trim().PadRight(35, ' ') +
                     Addr1.PadRight(35, ' ') + Addr2.PadRight(35, ' ') + Addr3.PadRight(35, ' ') + Addr4.PadRight(35, ' ') +
                     Addr5.PadRight(35, ' ') + " ".PadRight(70, ' ') + PostCode.PadRight(5, ' ') + "ZAF" +
                     "IND" + " ".PadRight(57, ' ') + HID.PadRight(12, ' ') + " ".PadRight(13, ' '));
             }
             if (NationalId == "" || NationalId.Length < 13)
             {
                 sw.Write(" ".PadRight(1142, ' ') + " ".PadRight(1456, ' ') + Environment.NewLine);
             }
             else
             {
                 sw.Write("Z" + NationalId.PadRight(16, ' ') + " ".PadRight(1125, ' ') + " ".PadRight(1456, ' ') + Environment.NewLine);
             }
             ShareTotal = ShareTotal + currentbal;
             ShareOld = ShareOld + oldbal;
             holdercount++;

     }
     sr.Close();
     sw.Close();
     setFilename(lblShareTotals, ShareTotal.ToString());
     setFilename(lblHolderTotal, holdercount.ToString());
     setFilename(lblOldBalanceTotals, ShareOld.ToString());
     this.progressBar1.Invoke(new updateBar(this.finalizeProcess));
     MessageBox.Show("Completed Processing Holder File", "Holder File Completed",
         MessageBoxButtons.OK, MessageBoxIcon.Information);
     setText(this, "Holder File Processing Completed");
 }

 private void convertCert()
 {
     string infile;
     infile = txtboxSelectFile.Text;
     string outfile;
     outfile = saveFileDialog1.FileName;
     string holdline;
     Int64 currentbal = 0;
     long ShareTotal = 0;
     int totaltrans = 0;
     StreamReader sr = new StreamReader(infile);
     StreamWriter sw = new StreamWriter(outfile);
     setText(this, "Start Certificate File Conversion");
     while (!sr.EndOfStream)
     {
         holdline = sr.ReadLine();
         string HID = holdline.Substring(0, 10);
         string day = holdline.Substring(10, 2);
         string month = holdline.Substring(13, 2);
         string year = holdline.Substring(16, 4);
         string cert = holdline.Substring(20, 10).Trim();
         string transaction = holdline.Substring(30, 55).TrimEnd();
         string shares = holdline.Substring(85, 18);
         setText(this, "Processing HolderID: " + HID);
         if (chkoxCreateCerts.Checked)
         {
             if (shares != "000000000000000000")
             {
                 sw.WriteLine(" ".PadRight(5, ' ') + "CAPIN" + " ".PadRight(8, ' ') +
                     day + month + year.Substring(2, 2) + "+" + shares.Substring(4, 14) + "000000" +
                     "ORD" + "ZAF" + " ".PadRight(5, ' ') + "C" + HID + " ".PadRight(10, ' ') +
                     cert.PadLeft(12, '0') + " ".PadRight(2911, ' '));
                 currentbal = Convert.ToInt64(shares);
                 ShareTotal = ShareTotal + currentbal;
             }
         }
         else
         {
             if (shares != "000000000000000000")
             {
                 sw.WriteLine(" ".PadRight(5, ' ') + "ADJIN" + " ".PadRight(8, ' ') +
                     day + month + year.Substring(2, 2) + "+" + shares.Substring(4, 14) + "000000" +
                     "ORD" + "ZAF" + " ".PadRight(5, ' ') + "C" + HID + " ".PadRight(10, ' ') +
                     cert.PadLeft(12, '0') + " ".PadRight(2911, ' '));
                 currentbal = Convert.ToInt64(shares);
                 ShareTotal = ShareTotal + currentbal;
             }
         }
         totaltrans++;
     }
     setFilename(lblCertificateTotals, totaltrans.ToString());
     setFilename(lblCertificateBalance, ShareTotal.ToString());
     sr.Close();
     sw.Close();
     this.progressBar1.Invoke(new updateBar(this.finalizeProcess));
     MessageBox.Show("Completed Processing Certificate File", "Certificate File Completed",
         MessageBoxButtons.OK, MessageBoxIcon.Information);
     setText(this, "Certificate File Processing Completed");
 }

 private void convertDiv()
 {
     //Declare Input File
     string infile;
     //Point to Input File
     infile = txtboxSelectFile.Text;
     //Declare output File
     string outfile;
     //Point to Output File
     outfile = saveFileDialog1.FileName;
     //Declare Lines of data
     string holdline;
     int totalCount = 0;
     //Declare File Reader
     StreamReader sr = new StreamReader(infile);
     StreamWriter swb = new StreamWriter(outfile);
     setText(this, "Start Payment Instruction Conversion");
     while (!sr.EndOfStream)
     {
         holdline = sr.ReadLine();
         string HID = holdline.Substring(0, 10);
         string BranchCode = holdline.Substring(591, 6);
         string AccountNumber = holdline.Substring(597, 16);
         string shares = holdline.Substring(85, 18);
         string newBranch = BranchCode.Substring(0, 3) + "-" + BranchCode.Substring(3, 3);
         setText(this, "Processing HolderID: " + HID);
         if (BranchCode != "      ")
         {
             if (shares != "000000000000000000")
             {
                 swb.WriteLine(" ".PadRight(5, ' ') + "PIADD" + " ".PadRight(7, ' ') + "C" + HID + "10" +
                     "D" + "   " + newBranch.PadRight(10, ' ') + AccountNumber.PadRight(16, ' ') + " ".PadRight(2940, ' '));
                 totalCount++;
             }
         }
     }
     sr.Close();
     swb.Close();
     setFilename(lblPaymentInstrucTotals, totalCount.ToString());
     this.progressBar1.Invoke(new updateBar(this.finalizeProcess));
     MessageBox.Show("Completed PIADD Conversion", "PIADD Conversion Message",
         MessageBoxButtons.OK, MessageBoxIcon.Information);
     setText(this, "Payment Instruction File Processing Completed");
 }


 private void convertDividendPayments()
 {
     string filePath;
     string inFile;
     string holdLine;
     inFile = txtboxSelectFile.Text;
     filePath = folderBrowserDialog1.SelectedPath;
     long TotalGross = 0;
     long TotalTax = 0;
     long TotalNet = 0;
     Int64 gross = 0;
     Int64 tax = 0;
     Int64 net = 0;
     StreamReader sr = new StreamReader(inFile);
     StreamWriter swp = new StreamWriter(Path.Combine(filePath, "er_au_xxxx_seqmpd.temp"));
     setText(this, "Starting Payment File Conversions");
     while (!sr.EndOfStream)
     {
         holdLine = sr.ReadLine();
         string DividendNumber = holdLine.Substring(0, 9).TrimEnd();
         string CADescription = holdLine.Substring(9, 55);
         string HolderRef = holdLine.Substring(64, 10);
         string PaymentType = holdLine.Substring(74, 1);
         string PaymentRef = holdLine.Substring(75, 10);
         string LdrBal = holdLine.Substring(85, 18);
         string GrossAmount = holdLine.Substring(103, 18);
         string TaxAmount = holdLine.Substring(121, 18);
         string NetAmount = holdLine.Substring(139, 18);
         string PaymentStatus = holdLine.Substring(157, 1);
         string PaymentDate = holdLine.Substring(158, 10);
         gross = Convert.ToInt64(GrossAmount);
         tax = Convert.ToInt64(TaxAmount);
         net = Convert.ToInt64(NetAmount);
         setText(this, "Processing HolderID: " + HolderRef);
         swp.Write("C" + HolderRef + "DIV" + DividendNumber + PaymentRef.Substring(2, 8).PadLeft(8, '0'));

         if (PaymentType == "E")
         {
             swp.Write("D" + PaymentDate.Substring(0, 2) + PaymentDate.Substring(3, 2) + PaymentDate.Substring(6, 4));

         }
         else
         {
             swp.Write(PaymentType + " ".PadRight(8, ' '));
         }
         swp.Write(GrossAmount.Substring(7, 11) + "00" + TaxAmount.Substring(7, 11) + "00" + NetAmount.Substring(7, 11) + "00" + "S");
         if (PaymentStatus == "P")
         {
             swp.Write("2");
         }
         if (PaymentStatus == "C")
         {
             swp.Write("3");
         }
         if (PaymentStatus == "U")
         {
             swp.Write("1");
         }
         if (PaymentStatus == "R")
         {
             swp.Write("E");
         }
         swp.Write("R" + " ".PadRight(24, ' ') + Environment.NewLine);
         TotalGross = TotalGross + gross;
         TotalTax = TotalTax + tax;
         TotalNet = TotalNet + net;
     }

     sr.Close();
     swp.Close();
     setFilename(lblGrossTotals, TotalGross.ToString());
     setFilename(lblTaxTotals, TotalTax.ToString());
     setFilename(lblNetTotals, TotalNet.ToString());
     this.progressBar1.Invoke(new updateBar(this.finalizeProcess));
     MessageBox.Show("Completed Dividend Payment Processing", "Dividend Processing",
         MessageBoxButtons.OK, MessageBoxIcon.Information);
     setText(this, "Dividend File Processing Completed");
 }

 #endregion

Excellence is doing ordinary things extraordinarily well.

Re: Threading

OriginalGriff9-Feb-10 23:25

OriginalGriff

9-Feb-10 23:25

Without actually running it, I can't see anything obviously wrong.
Since this is the code that (doesn't) show the problem, I would be tempted to try

private void setFilename(Control lblctrl, string filename)
{
    Console.WriteLine("setFileName Entered: " + lblCtrl.Name + " : " + filename);
    if (this.WindowState == FormWindowState.Minimized)
        return;
    Console.WriteLine("setFileName PreInvokeCheck: " + lblCtrl.Name + " : " + filename);
    if (lblctrl.InvokeRequired)
        {
        Console.WriteLine("setFileName BeginInvoke: " + lblCtrl.Name + " : " + filename);
        lblctrl.BeginInvoke(new SetLabel(setFilename), new object[] { lblctrl, filename });
        }
    else
        {
        Console.WriteLine("setFileName Direct: " + lblCtrl.Name + " : " + filename);
        lblctrl.Text = filename;
        }
}

Or equivilent to check if it gets to the "setFileName Direct" bit when you don't get the label written. It may give a clue to what is going on (or worse, remove the problem)

If Barbie is so popular, why do you have to buy her friends?

Eagles may soar, but weasels don't get sucked into jet engines.

If at first you don't succeed, destroy all evidence that you tried.

Re: Threading

MumbleB9-Feb-10 23:35

MumbleB

9-Feb-10 23:35

Thanks mate. I will give it a go and post back. It is just strange that it does it for two consecutive runs but for the third and fourth it doesn't. And it doesn't matter in what order it is run or not.

Excellence is doing ordinary things extraordinarily well.

Re: Threading

Luc Pattyn10-Feb-10 1:57

Luc Pattyn

10-Feb-10 1:57

Hi,

you are not supposed to touch a Control from a thread that did not create the Control. While your code is using several InvokeRequired/Invoke patterns, it is also not using them in several locations, see:

1.
if (this.WindowState == FormWindowState.Minimized)
is probably OK, but not documented to be OK

2.
infile = txtboxSelectFile.Text;
is probably not OK (not documented, I guess it is not OK for Controls that allow text editing)

3.
outfile = saveFileDialog1.FileName;
is most likely not OK, file dialogs are known to be critical (e.g. you need STAThread for them)

IMO you should fix all of the above.

Smile | :)

Luc Pattyn [Forum Guidelines] [Why QA sucks] [My Articles]

I only read code that is properly formatted, adding PRE tags is the easiest way to obtain that.
All Toronto weekends should be extremely wet until we get it automated in regular forums, not just QA.

Loading an assembly from a new AppDoamin

ThetaClear9-Feb-10 20:28

ThetaClear

9-Feb-10 20:28

Hi Guys,

I'm trying to do something that looks easy but for some reason doesn't work.
I have a window service which loads .dll's that are in a different directory every couple of minutes.
I need to update those .dll's every now an than so I created an AppDomin and from there I want to load the .dll's in to the main AppDomain.
The strange thing is when I try to load a .dll I get an exception that the .dll can't be found.
Here's the source code:

AppDomainSetup AppDomSetup = new AppDomainSetup();
                AppDomSetup.ApplicationName = "Service Name";
                AppDomSetup.ApplicationBase = Application.StartupPath;
                AppDomSetup.PrivateBinPath = "alerts";
                AppDomSetup.ShadowCopyFiles = "true";
                AppDomSetup.CachePath = Path.Combine(Application.StartupPath, "_cache");
                m_FilesDomain = AppDomain.CreateDomain("Ksm Scheduler", null , AppDomSetup);
                m_FilesDomain.Load("alert1.dll");

The 'PrivateBinPath' property points to the directory that contains the .dll's.
The 'cache path' folder IS CREATED but I get an exception. When I place the .dll's in the 'ApplicationBase' directory i.e. in the directory of the .exe file, the .dll is loaded.

Thanks for any help,

Avi

Re: Loading an assembly from a new AppDoamin

Rob Philpott10-Feb-10 0:11

Rob Philpott

10-Feb-10 0:11

Don't have an answer to your immediate questions, but a couple of queries. Firstly, are all these DLLs .NET assemblies? Are you using shadowing so you don't lock the file in question so it can be altered elsewhere? When a dll is changed, do you want to unload the last one and replace it with the new one?

The bit which sounds really odd is loading the dll into the main application domain (which you can't unload). Do you not want to create a new domain, load the dlls in there and then unload it when they need to be updated?

Regards,
Rob Philpott.

Re: Loading an assembly from a new AppDoamin

ThetaClear10-Feb-10 9:53

ThetaClear

10-Feb-10 9:53

Hi Rob,
1.

Rob Philpott wrote:
are all these DLLs .NET assemblies?

Yes, all the DLL's .NET assemblies.

2.

Rob Philpott wrote:
Are you using shadowing so you don't lock the file in question so it can be altered elsewhere?

Yes I'm.

3.

Rob Philpott wrote:
When a dll is changed, do you want to unload the last one and replace it with the new one?

Yes, exactly.

Rob Philpott wrote:
Do you not want to create a new domain, load the dlls in there and then unload it when they need to be updated?

I DO want to create a NEW domain, which I did, but for some reason the .dll aren't loaded into it. Besides, Although I don't understand how the .dll file, after is was updated, gets updated also in the new doamin without me unloading it i.e. I don't want to unload the .dll when it's changed. That is the whole purpose of shdowing, right? ( or wrong?)

One more important thing.
If I place the .dll's inside the ApplicationBase directory, the .dll's ARE loaded. When I create the new domain I give it a AppDomainSetup object with all the details. I assign to the PrivateBinPath the folder which the .dll's reside ( the folder is inside the main application folder, of course)

RSync

satsumatable9-Feb-10 19:22

satsumatable

9-Feb-10 19:22

Hi
Is there any open source library C#/C++/C which will give me the delta changes of file (it can be any type)?

Thanks ...

Preventing the dropdown from being opened when drop down button pressed in combobox?

Ron.bharath9-Feb-10 18:53

Ron.bharath

9-Feb-10 18:53

Hello All,

I have an issues, i want to cancel the dropdown from being opened after validating the dropdown button clicked.

i tried with setting droppeddown property to true as suggested by one of the member from this forum in earlier post. But that is also not avoiding the dropdown from being opened.

I also tried to override the wndProc method and canceling the event it self but that is also not working . Please suggest me what i need to do so that i can avoid the dropdown after custom validation.

Thanks in Advance.
Ron

Re: Preventing the dropdown from being opened when drop down button pressed in combobox?

Hessam Jalali10-Feb-10 1:25

Hessam Jalali

10-Feb-10 1:25

Hello, I think this can be done by intercepting WM_COMMAND message in "WndProc" method.

this may help

public class SuperComboBox:ComboBox
    {
        public class DropDownValidate:EventArgs
        {
            public bool AllowDropDown{get;set;}

            public DropDownValidate()
            {
                this.AllowDropDown = true;
            }
        }

        private const int WM_COMMAND = 0x0111;

        public event EventHandler<DropDownValidate> ValidateOnDropDown;

        private bool _haltDrop;

        protected virtual void OnValidateDropDown(DropDownValidate e)
        {
            if (this.ValidateOnDropDown != null)
                this.ValidateOnDropDown(this, e);
        }

        protected override void WndProc(ref Message m)
        {
            if (m.Msg == WM_COMMAND)
            {
                var validationArg = new DropDownValidate();
                this.OnValidateDropDown(validationArg);
                _haltDrop = !validationArg.AllowDropDown;
                if (_haltDrop) return;
            }
            base.WndProc(ref m);
        }
    }

Good luck

SuspendLayout ResumeLayout Question

Douglas Kirk9-Feb-10 18:52

Douglas Kirk

9-Feb-10 18:52

I have a project with many object within objects and it take a while for it to refresh when the data is changed or the form is resized. I think I have too many daisy chained events occuring.

I notice that when the Visual C# produces code it will put the "new" declarations before the SuspendLayout statement.

Object = new MediaIcon;
this.SuspendLayout();
Object.Left = 10;
.....
this.Controls.Add(Object);
this.ResumeLayout(false);
this.PerformLayout();

this is simple for a one of object, but when you have an array of them can you put the new commands within the bounds of the Suspend/Resume??

this.SuspendLayout();

Object = new MediaIcon[25];

for (int n = 0; n < 25; n++)
{
Object[n] = new MediaIcon();
Object[n].Tag = n;
.....
Object[n].Enter += new System.EventHandler(ClickButton);
this.Controls.Add(Object[n]);
}
FunctionIndex = MainForm.FunctionIndex;

this.Resize += new System.EventHandler(this.MediaBrowserClass_Resize);
this.Enter += new System.EventHandler(this.MediaBrowserClass_Enter);

this.ResumeLayout(false);
this.PerformLayout();

Could the way I am using the Suspend/Resume be the root cause of my slow refreshing?

Thank you in advance

Re: SuspendLayout ResumeLayout Question

Dave Kreskowiak10-Feb-10 2:07

Dave Kreskowiak

10-Feb-10 2:07

Douglas Kirk wrote:
I notice that when the Visual C# produces code it will put the "new" declarations before the SuspendLayout statement.

So what? The new control hasn't been added to the form's Controls collection yet, so it's not going to affect the layout of the form. it's perfectly logical to place the new outside of the suspend/resume layout block.

Douglas Kirk wrote:
this is simple for a one of object, but when you have an array of them can you put the new commands within the bounds of the Suspend/Resume??

You can, but it doesn't change anything at all.

Douglas Kirk wrote:
Could the way I am using the Suspend/Resume be the root cause of my slow refreshing?

No. Creating controls is a very expensive operation. If you're doing this on every refresh of the form, your creating a ton of controls every time something is dragged over your form.

A guide to posting questions on CodeProject[^]

Dave Kreskowiak
Microsoft MVP
Visual Developer - Visual Basic
2006, 2007, 2008
But no longer in 2009...

Re: SuspendLayout ResumeLayout Question

Luc Pattyn10-Feb-10 2:09

Luc Pattyn

10-Feb-10 2:09

Hi,

1.
please always show code inside PRE tags (e.g. use the "code block" widget), that makes it much more readable.
I may have overlooked something as it is now.

2.

Douglas Kirk wrote:
can you put the new commands within the bounds of the Suspend/Resume??

yes. And IMO it won't make a difference.

3.

Douglas Kirk wrote:
this.Controls.Add(Object[n]);

When you need to add a number of Controls, it is sometimes faster to use Controls.AddRange(), which Visual Designer also does.

4.
Not sure how long your constructors take, e.g. new MediaIcon(); that would depend on your code (not shown).

5.

Douglas Kirk wrote:
it take a while for it to refresh when ... the form is resized.

That is not related to the code shown; it tells me your form probably is too complex. How many Controls are there? Do they overlap? Are there any background images? playing with transparency?

Smile | :)

Luc Pattyn [Forum Guidelines] [Why QA sucks] [My Articles]

modified on Friday, February 12, 2010 4:44 AM

Rss

kk.tvm9-Feb-10 18:21

kk.tvm

9-Feb-10 18:21

Hi friends

How to read news from a rss feed in c#

thanks in advance

-kk.tvm-

Re: Rss

Arun Jacob9-Feb-10 19:13

Arun Jacob

9-Feb-10 19:13

Lot of samples are there if you try Google. Here is one,

Simple RSS Reader in C#[^]

Arun Jacob
http://codepronet.blogspot.com/

Re: Rss

Giorgi Dalakishvili9-Feb-10 19:32

Giorgi Dalakishvili

9-Feb-10 19:32

You can use Rss Toolkit[^] or just parse it yourself as it is just an xml.

Giorgi Dalakishvili

#region signature
My Articles

Browsing xkcd in a windows 7 way[^]

#endregion

IEnumerable Min() not working as expected

Member 39190499-Feb-10 16:43

Member 3919049

9-Feb-10 16:43

I have a List of rows/classes returned from a strong-typed DataSet.

I've written a lambda statement on it to return all of the rows that match the lambda.

I pass the lambda statement through a Select method on the IEnumerable List.

At the end of the select method I have the option to select the Min() method.

However, the Min statement returns a bool from this implementation.

I'm trying to get the min value of the column referenced in the lambda.

What do I need to do to get the Min to return an int based on a given int column in the result set?

Re: IEnumerable Min() not working as expected

Dave Kreskowiak10-Feb-10 2:02

Dave Kreskowiak

10-Feb-10 2:02

Without seeing your code, it's impossible to say where you screwed up.

A guide to posting questions on CodeProject[^]

Dave Kreskowiak
Microsoft MVP
Visual Developer - Visual Basic
2006, 2007, 2008
But no longer in 2009...

What is the use of e.Handled in the KeyDown event

Kalvin @ Work9-Feb-10 11:04

Kalvin @ Work

9-Feb-10 11:04

As far as I have been able to tell setting e.Handled to true does absolutely nothing. I'm wondering why it's even available for the KeyDown event. Could someone please tell me?

I have looked at the documentation for the textbox control and the KeyDown checks the value and sets some class variable, then the KeyPress checks that variable and sets e.Handled based on the value of the variable.

Thank you.

- Kalvin

Re: What is the use of e.Handled in the KeyDown event

loyal ginger9-Feb-10 11:22

loyal ginger

9-Feb-10 11:22

If you derive a class from TextBox, handle KeyDown event, and set Handled to true, that control will not pass the key press events to the underlying Win32 text box control, but it will still display the characters that the user typed. Set it to false so that the underlying Win32 text box control can do the default handling.

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