Re: COM exception loss - C# Discussion Boards

Re: How to read from serial port until timeout of no more data received?

Richard MacCutchan8-Oct-20 23:55

8-Oct-20 23:55

There is a good article and sample at Serial Port I/O[^]. The code is in C but it should be reasonably clear what the sequence of events should be.

My (temporary?) solution

td17769-Oct-20 12:25

td1776

9-Oct-20 12:25

For the time being, I am using a timer, storing the data until the timer is elapsed, and resetting the timer if new data comes before it has elapsed.

in DataReceived:

// stop timer
// start timer
try
{
	while (myPort.BytesToRead > 0)
		logText += myPort.ReadExisting();   
}
catch (Exception ex)
	// handle exception

in elapsed timer event handler:

// stop timer
// display timer
// write file
// clear data buffer (String)

It seems to be operating as expected, with the acceptable artificial latency discussed in comments while it waits for the timer to expire, capturing and storing subsequent data bursts received within the timer interval in a single chunk.

COM exception loss

Member 126326017-Oct-20 21:57

Member 12632601

7-Oct-20 21:57

I call COM object method, it generate exception. If call from VB project or from Excel VBA I get detail exception information (original text exception message from COM object method). But if call from C# project I receive only NullReferenceException. InnerException field is empty. What can do to get detail exception info from c#?

Re: COM exception loss

Richard MacCutchan7-Oct-20 22:35

Richard MacCutchan

7-Oct-20 22:35

Member 12632601 wrote:
I receive only NullReferenceException

There is not much more that the exception handler can tell you. You need to use your debugger to find out which reference item is null, and why.

Re: COM exception loss

Member 126326017-Oct-20 23:03

Member 12632601

7-Oct-20 23:03

My code similar:

dynamic result = comobject.ExecuteQuery();

On this line debug stoped at exception NullReferenceexception.
Known what method ExcecuteQuery throw exception in message contain error description

But i no can get this message in c#

Re: COM exception loss

Richard MacCutchan7-Oct-20 23:25

Richard MacCutchan

7-Oct-20 23:25

Use the debugger to examine all the reference items. One of them is null when it should not be.

Re: COM exception loss

Member 126326017-Oct-20 23:58

Member 12632601

7-Oct-20 23:58

ComObject is not null. What in this line can by null?
In VB same line
throw exception TargetInvocationException what have not null InnerException field. What contain detail error message.

Re: COM exception loss

Richard MacCutchan8-Oct-20 0:24

Richard MacCutchan

8-Oct-20 0:24

I have no idea because I cannot examine your running program.

Re: COM exception loss

OriginalGriff8-Oct-20 5:10

OriginalGriff

8-Oct-20 5:10

At a guess, some of the information on which the ExecuteQuery request depends.

Use the debugger: look at the ComObject and it's properties - are there any there that are null, that it might be using?

We can't do that for you: we have no idea what yoru object is, what it is talking to, what data it might require - and no way to find out as we can't run your code under the same conditions you do!

So break out the debugger, and start looking at exactly what is going on!

"I have no idea what I did, but I'm taking full credit for it." - ThisOldTony
"Common sense is so rare these days, it should be classified as a super power" - Random T-shirt
AntiTwitter: @DalekDave is now a follower!

Scanning for servers

pkfox4-Oct-20 22:52

pkfox

4-Oct-20 22:52

Hi all, the code below broadcasts on a lan for Logitech media servers listening on UDP port 3483 - it works perfectly unless I run it more than once in the same session which results in the error Only one usage of each socket address is normally permitted. Now I understand that you can't bind to a socket twice with the same ip/port pairing but I'm not trying to do that - I'm simply resending the broadcast. I don't have servers running on the same machine as this code is run on ( that's bitten me before ) Any ideas ?

public async Task<LMSResponseParser> ScanForServer()
     {
         try
         {
             this.listener = new UdpClient(UDPPort); // This is where it bombs on the second run
             this.ReceiveIP = new IPEndPoint(IPAddress.Broadcast, UDPPort);
             this.Result = await listener.ReceiveAsync();
             // The buffer should contain "eIPAD0\JSON0\UUID0\VERS0" in a byte array
             this.RequestData = this.Result.Buffer;
             this.ReceiveIP = this.Result.RemoteEndPoint;
             // Send the buffer back to initiate a response
             this.BytesSent = await this.listener.SendAsync(this.RequestData, this.RequestData.Length, this.ReceiveIP);

             this.Result = await this.listener.ReceiveAsync();
             // This should contain information about our server ( Port number , IP etc etc )
             this.BytesReceived = this.Result.Buffer;

             if (this.BytesReceived != null && this.BytesReceived.Length > 0)
                 this.RetVal = Encoding.UTF8.GetString(this.BytesReceived);
             // Parse the response and place the values in a dictionary
             this.parseLMSResponse = new LMSResponseParser(BytesReceived);
         }
         catch (Exception ex)
         {
             Console.WriteLine(ex.Message);
         }
         finally
         {
             if (this.listener != null && this.listener.Client.Connected)
                 this.listener.Close();
         }
         return this.parseLMSResponse;
     }

"I didn't mention the bats - he'd see them soon enough" - Hunter S Thompson - RIP

modified 5-Oct-20 5:30am.

Re: Scanning for servers

Richard Deeming5-Oct-20 3:44

Richard Deeming

5-Oct-20 3:44

The UspClient class implements IDisposable, so you could try wrapping it in a using block.

I'd also be inclined to use local variables for objects which aren't meant to live beyond the current method, rather than storing everything in class-level fields.

public async Task<LMSResponseParser> ScanForServer()
{
    using (var listener = new UdpClient(UDPPort))
    {
        this.ReceiveIP = new IPEndPoint(IPAddress.Broadcast, UDPPort);
        
        var result = await listener.ReceiveAsync();
        var requestData = result.Buffer;
        this.ReceiveIP = result.RemoteEndPoint;
        
        this.BytesSent = await listener.SendAsync(requestData, requestData.Length, this.ReceiveIP);
        
        result = await listener.ReceiveAsync();
        var bytesReceived = result.Buffer;
        if (bytesReceived != null && bytesReceived.Length != 0)
        {
            this.RetVal = Encoding.UTF8.GetString(bytesReceived);
        }
        
        return new LMSResponseParser(bytesReceived);
    }
}

"These people looked deep within my soul and assigned me a number based on the order in which I joined."
- Homer

Re: Scanning for servers

pkfox5-Oct-20 4:44

pkfox

5-Oct-20 4:44

Thanks Richard I'll give it a shot

"I didn't mention the bats - he'd see them soon enough" - Hunter S Thompson - RIP

Re: Scanning for servers

pkfox5-Oct-20 5:17

pkfox

5-Oct-20 5:17

Hi Richard, I tried your code and it worked fine, I think it's the using statement that's key here - I modded my code to call Dispose() on the listener object and that also worked fine so I think you nailed it noticing UDPClient implements IDispose - a lesson learnt - thanks for your help

"I didn't mention the bats - he'd see them soon enough" - Hunter S Thompson - RIP

version mismatch

Member 149246074-Oct-20 10:30

Member 14924607

4-Oct-20 10:30

Visual studio 2019 16.7.5

I'm getting this warning":

Version mismatch between the analyzer package '3.3.1' and Microsoft.CodeAnalysis '2.1.0.0'

I have the latest version of Microsoft.CodeAnalysis and FxCopAnalyser installed.

I don't understand what causes the system to look at Microsoft.CodeAnalysis '2.1.0.0'.

Re: version mismatch

Richard Deeming5-Oct-20 3:33

Richard Deeming

5-Oct-20 3:33

Looks like the same problem that was already reported:
VS Mac build fails after adding FxCopAnalyzer package · Issue #2289 · dotnet/roslyn-analyzers · GitHub[^]

NB: The latest released version of Microsoft.CodeAnalysis is 3.7.0:
Microsoft.CodeAnalysis 3.7.0[^]

The latest released version of Microsoft.CodeAnalysis.FxCopAnalyzers is 3.3.0:
Microsoft.CodeAnalysis.FxCopAnalyzers 3.3.0[^]
Although it's listed as "prerelease" on the GitHub site:
Release v3.3.0 · dotnet/roslyn-analyzers · GitHub[^]

Where have you found v3.3.1 of FxCopAnalyzers, since it's not on NuGet or GitHub?

"These people looked deep within my soul and assigned me a number based on the order in which I joined."
- Homer

Re: version mismatch

Member 149246075-Oct-20 8:45

Member 14924607

5-Oct-20 8:45

I have installed MicroCodeAnalysis v3.70 and FxCopAnalyzers v3.3.0. I don't have version 3.3.1

Re: version mismatch

Richard Deeming5-Oct-20 22:22

Richard Deeming

5-Oct-20 22:22

Member 14924607 wrote:
I don't have version 3.3.1

Member 14924607 wrote:
Version mismatch between the analyzer package '3.3.1' ...

The error message suggests you do. Unless there's a different analyzer package installed which you haven't mentioned?

"These people looked deep within my soul and assigned me a number based on the order in which I joined."
- Homer

printDocument

Member 149437371-Oct-20 20:02

Member 14943737

1-Oct-20 20:02

Hi,

I am using the printDocument function to print out my datagridview data. However, I am using the debugger to trace my program execution and I have found out that the "printDocument1_BeginPrint" and "printDocument1_PrintPage" never get executed during the program execution.

Can anyone tell me what I have done wrong? Why the printDocument1_PrinPage and printDoucument1_BeginPrint never got executed?

PS. I am pasting my code below of the printing logic.

Thanks,
John

#region Print Button Click Event
        /// <summary>
        /// Handles the print button click event
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void btnPrint_Click(object sender, EventArgs e)
        {
            //Open the print dialog
            PrintDialog printDialog = new PrintDialog();
            PrintDocument printDocument1 = new PrintDocument();
            printDialog.Document = printDocument1;
            printDialog.UseEXDialog = true;

            //Get the document
            if (DialogResult.OK == printDialog.ShowDialog())
            {
                printDocument1.DocumentName = "Lottery Tickets Priniting";
                printDocument1.Print();
            }

            //Open the print preview dialog
            //PrintPreviewDialog objPPdialog = new PrintPreviewDialog();
            //objPPdialog.Document = printDocument1;
            //objPPdialog.ShowDialog();
        }
        #endregion

        #region Begin Print Event Handler
        /// <summary>
        /// Handles the begin print event of print document
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void printDocument1_BeginPrint(object sender, System.Drawing.Printing.PrintEventArgs e)
        {
            try
            {
                strFormat = new StringFormat();
                strFormat.Alignment = StringAlignment.Near;
                strFormat.LineAlignment = StringAlignment.Center;
                strFormat.Trimming = StringTrimming.EllipsisCharacter;

                arrColumnLefts.Clear();
                arrColumnWidths.Clear();
                iCellHeight = 0;
                iRow = 0;
                bFirstPage = true;
                bNewPage = true;

                // Calculating Total Widths
                iTotalWidth = 0;
                foreach (DataGridViewColumn dgvGridCol in dataGridView1.Columns)
                {
                    iTotalWidth += dgvGridCol.Width;
                }
            }
            catch (Exception ex)
            {
                MessageBox.Show(ex.Message, "Error", MessageBoxButtons.OK, MessageBoxIcon.Error);
            }
        }
        #endregion

        #region Print Page Event
        /// <summary>
        /// Handles the print page event of print document
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void printDocument1_PrintPage(object sender, System.Drawing.Printing.PrintPageEventArgs e)
        {
            try
            {
                //Set the left margin
                int iLeftMargin = e.MarginBounds.Left;
                //Set the top margin
                int iTopMargin = e.MarginBounds.Top;
                //Whether more pages have to print or not
                bool bMorePagesToPrint = false;
                int iTmpWidth = 0;

                //For the first page to print set the cell width and header height
                if (bFirstPage)
                {
                    foreach (DataGridViewColumn GridCol in dataGridView1.Columns)
                    {
                        iTmpWidth = (int)(Math.Floor((double)((double)GridCol.Width /
                                       (double)iTotalWidth * (double)iTotalWidth *
                                       ((double)e.MarginBounds.Width / (double)iTotalWidth))));

                        iHeaderHeight = (int)(e.Graphics.MeasureString(GridCol.HeaderText,
                                    GridCol.InheritedStyle.Font, iTmpWidth).Height) + 11;

                        // Save width and height of headres
                        arrColumnLefts.Add(iLeftMargin);
                        arrColumnWidths.Add(iTmpWidth);
                        iLeftMargin += iTmpWidth;
                    }
                }
                //Loop till all the grid rows not get printed
                while (iRow <= dataGridView1.Rows.Count - 1)
                {
                    DataGridViewRow GridRow = dataGridView1.Rows[iRow];
                    //Set the cell height
                    iCellHeight = GridRow.Height + 5;
                    int iCount = 0;
                    //Check whether the current page settings allo more rows to print
                    if (iTopMargin + iCellHeight >= e.MarginBounds.Height + e.MarginBounds.Top)
                    {
                        bNewPage = true;
                        bFirstPage = false;
                        bMorePagesToPrint = true;
                        break;
                    }
                    else
                    {
                        if (bNewPage)
                        {
                            //Draw Header
                            e.Graphics.DrawString("Lottery Tickets Listing", new Font(dataGridView1.Font, FontStyle.Bold),
                                    Brushes.Black, e.MarginBounds.Left, e.MarginBounds.Top -
                                    e.Graphics.MeasureString("Lottery Tickets Listing", new Font(dataGridView1.Font,
                                    FontStyle.Bold), e.MarginBounds.Width).Height - 13);

                            String strDate = DateTime.Now.ToLongDateString() + " " + DateTime.Now.ToShortTimeString();
                            //Draw Date
                            e.Graphics.DrawString(strDate, new Font(dataGridView1.Font, FontStyle.Bold),
                                    Brushes.Black, e.MarginBounds.Left + (e.MarginBounds.Width -
                                    e.Graphics.MeasureString(strDate, new Font(dataGridView1.Font,
                                    FontStyle.Bold), e.MarginBounds.Width).Width), e.MarginBounds.Top -
                                    e.Graphics.MeasureString("Lottery Tickets Listing", new Font(new Font(dataGridView1.Font,
                                    FontStyle.Bold), FontStyle.Bold), e.MarginBounds.Width).Height - 13);

                            //Draw Columns                 
                            iTopMargin = e.MarginBounds.Top;
                            foreach (DataGridViewColumn GridCol in dataGridView1.Columns)
                            {
                                e.Graphics.FillRectangle(new SolidBrush(Color.LightGray),
                                    new Rectangle((int)arrColumnLefts[iCount], iTopMargin,
                                    (int)arrColumnWidths[iCount], iHeaderHeight));

                                e.Graphics.DrawRectangle(Pens.Black,
                                    new Rectangle((int)arrColumnLefts[iCount], iTopMargin,
                                    (int)arrColumnWidths[iCount], iHeaderHeight));

                                e.Graphics.DrawString(GridCol.HeaderText, GridCol.InheritedStyle.Font,
                                    new SolidBrush(GridCol.InheritedStyle.ForeColor),
                                    new RectangleF((int)arrColumnLefts[iCount], iTopMargin,
                                    (int)arrColumnWidths[iCount], iHeaderHeight), strFormat);
                                iCount++;
                            }
                            bNewPage = false;
                            iTopMargin += iHeaderHeight;
                        }
                        iCount = 0;
                        //Draw Columns Contents                
                        foreach (DataGridViewCell Cel in GridRow.Cells)
                        {
                            if (Cel.Value != null)
                            {
                                e.Graphics.DrawString(Cel.Value.ToString(), Cel.InheritedStyle.Font,
                                            new SolidBrush(Cel.InheritedStyle.ForeColor),
                                            new RectangleF((int)arrColumnLefts[iCount], (float)iTopMargin,
                                            (int)arrColumnWidths[iCount], (float)iCellHeight), strFormat);
                            }
                            //Drawing Cells Borders 
                            e.Graphics.DrawRectangle(Pens.Black, new Rectangle((int)arrColumnLefts[iCount],
                                    iTopMargin, (int)arrColumnWidths[iCount], iCellHeight));

                            iCount++;
                        }
                    }
                    iRow++;
                    iTopMargin += iCellHeight;
                }

                //If more lines exist, print another page.
                if (bMorePagesToPrint)
                    e.HasMorePages = true;
                else
                    e.HasMorePages = false;
            }
            catch (Exception exc)
            {
                MessageBox.Show(exc.Message, "Error", MessageBoxButtons.OK, MessageBoxIcon.Error);
            }
        }
        #endregion

modified 2-Oct-20 1:56am.

Re: printDocument

Gerry Schmitz1-Oct-20 20:11

Gerry Schmitz

1-Oct-20 20:11

You didn't wire up your printing event handlers.

It was only in wine that he laid down no limit for himself, but he did not allow himself to be confused by it.
― Confucian Analects: Rules of Confucius about his food

Re: printDocument

Member 149437371-Oct-20 23:54

Member 14943737

1-Oct-20 23:54

Works great now. Thanks for the help.

Re: printDocument

OriginalGriff1-Oct-20 21:03

OriginalGriff

1-Oct-20 21:03

As Gerry has said, you need to add the handlers:

PrintDocument printDocument1 = new PrintDocument();
printDialog.Document = printDocument1;
printDocument1.BeginPrint += printDocument1_BeginPrint;
printDocument1_PrintPage += printDocument1_PrintPage;

But when you post a large chunk of code, please use the code widget to insert the pre tags - it preserves formatting and engages the appropriate syntax highlighter. I added them to your post, but without the you get this:

if (bMorePagesToPrint)
e.HasMorePages = true;
else
e.HasMorePages = false;

With them you get this:

                if (bMorePagesToPrint)
                    e.HasMorePages = true;
                else
                    e.HasMorePages = false;

which is a whole load more readable for everyone!
All the tags look like in a post is this:

<pre lang="cs">                if (bMorePagesToPrint)
                    e.HasMorePages = true;
                else
                    e.HasMorePages = false;</pre>

Re: printDocument

Member 149437371-Oct-20 23:37

Member 14943737

1-Oct-20 23:37

Thanks for the tips. I am new to this. Will do it next time when I post codes in here. Thanks again.

Re: printDocument

OriginalGriff1-Oct-20 23:40

OriginalGriff

1-Oct-20 23:40

You're welcome!

How to compare on DPFP.Template to another DPFP.Template

Member 144684061-Oct-20 4:07

Member 14468406

1-Oct-20 4:07

I want tout compare templates between them stored in my database.
Can you help me please

This is an example:

if (template1 == template2)
{
MessageBox.Show("Fingerprint matched");
}

Re: How to compare on DPFP.Template to another DPFP.Template

Gerry Schmitz1-Oct-20 5:49

Gerry Schmitz

1-Oct-20 5:49

What's the template made out of? Ink? A finger print template?

It was only in wine that he laid down no limit for himself, but he did not allow himself to be confused by it.
― Confucian Analects: Rules of Confucius about his food

Use Ctrl+Left/Right to switch messages, Ctrl+Up/Down to switch threads, Ctrl+Shift+Left/Right to switch pages.