Re: How To Write And Comsume An Async Method - C# Discussion Boards

Re: Problem with serial port

16-Jun-20 23:49

There there's something else going on that I can't see. I've done this dozens of times; with the changes to applicationHost.config and web.config, it just works.

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

Problem with serial port

DanTheBest14-Jun-20 5:48

DanTheBest

14-Jun-20 5:48

Hi,
i'm trying to print to an epson esc/pos printer using vb.net.
trying opening the serial post (the name is correct, i can see it dubuging) the execution goes in exception whith the error "Il nome specificato non inizia con COM/com o non si risolve in una porta seriale valida.Nome parametro: portName ParamName=portName"
This is my configuration code:
ADRPort = New System.IO.Ports.SerialPort(GLOBAL_DisplayCOMTkt, _
19200, _
Parity.None, _
8, _
StopBits.One)
...
...
...
...
If (ADRPort.IsOpen) Then
ADRPort.Close()
End If

If Not ADRPort.IsOpen Then
ADRPort.PortName = GLOBAL_DisplayCOMTkt
ADRPort.DtrEnable = False
ADRPort.RtsEnable = False
ADRPort.BaudRate = 19200
ADRPort.DataBits = 8
ADRPort.Parity = Parity.None
ADRPort.StopBits = StopBits.One
ADRPort.Handshake = Handshake.None
ADRPort.ReadTimeout = 2000
ADRPort.Open()
End If
Thanks for any support you can supply....
Fabio

OriginalGriff14-Jun-20 8:27

OriginalGriff

14-Jun-20 8:27

The error message is pretty explicit: "Invalid port name"

Quote:
The specified name does not begin with COM / com or does not resolve to a valid serial port. Parameter name: portName ParamName = portName "

So use the debugger, and look at exactly what you are setting the PortName property to: GLOBAL_DisplayCOMTkt has a value, but we have no idea what it is - and we can't do that for you!

"I have no idea what I did, but I'm taking full credit for it." - ThisOldTony
AntiTwitter: @DalekDave is now a follower!

How To Write And Comsume An Async Method

Kevin Marois12-Jun-20 6:47

12-Jun-20 6:47

I have code in my DAL that I want to call from the UI asynchronously in my WPF app. I think I have this right, but I'd like to get your opinion.

DAL Interface

public interface IDAL
{
    Task<List<ReportData>> GetReportData(ReportArgsEntity args);
}

DAL

public class MyDAL : IDAL
{
    public Task<List<ReportData>> GetReportData(ReportArgsEntity args)
    {
        var t = Task.Factory.StartNew(() => 
        {
            List<ReportData> results = new List<ReportData>();

            // Get report data here

            return results;
        });

        return t;
    }
}

BL Interface

public interface IBL
{
    Task<List<ReportData>> GetReportData(ReportArgsEntity args);
}

public class MyBL : IBL
{
    IDAL _dal;
    public MyBL()
    {
        _dal = new MyDAL();
    }
    public Task<List<ReportData>> GetReportData(ReportArgsEntity args)
    {
        return _dal.GetReportData(args);
    }
}

View Model

public class MyViewModel
{
    IBL _bizLayer;

    public MyViewModel()
    {
        _bizLayer = new MyBL();
    }

    private async void RunReport()
    {
        var args = new ReportArgsEntity()
        {
            // Set properties here
        };

        var reportData = await _bizLayer.GetReportData(args);

        // When the data comes back, show he report
    }
}

If it's not broken, fix it until it is.
Everything makes sense in someone's mind.
Ya can't fix stupid.

Richard Deeming12-Jun-20 8:09

12-Jun-20 8:09

I'm not convinced by that Task.Factory.StartNew call.

First of all, you should really be using Task.Run instead:
Task.Run vs Task.Factory.StartNew | .NET Parallel Programming[^]

But unless that code is CPU-bound, you've not really gained much. Most data access code is going to be IO-bound, so it should be using the async version of whatever methods you're using to load the data.

For example, if you're using a SqlCommand to load the data:
SqlConnection.OpenAsync(CancellationToken) Method (System.Data.SqlClient) | Microsoft Docs[^]
SqlCommand.ExecuteReaderAsync Method (System.Data.SqlClient) | Microsoft Docs[^]
SqlDataReader.ReadAsync(CancellationToken) Method (System.Data.SqlClient) | Microsoft Docs[^]

public async Task<List<ReportData>> GetReportData(ReportArgsEntity args)
{
    // Make sure we're not blocking the UI thread:
    await Task.Yield().ConfigureAwait(false);
    
    using (var connection = new SqlConnection("..."))
    using (var command = new SqlCommand("...", connection))
    {
       await connection.OpenAsync();
       
       using (var reader = await command.ExecuteReaderAsync(CommandBehavior.CloseConnection))
       {
           var results = new List<ReportData>();
           
           while (await reader.ReadAsync())
           {
               ...
           }
           
           return results;
       }
    }
}

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

Kevin Marois12-Jun-20 9:54

12-Jun-20 9:54

Richard Deeming wrote:
First of all, you should really be using Task.Run instead:

I thought Task.Run and Task.Factory.StartNew do basically the same thing?

I'm using Linq To SQL

If it's not broken, fix it until it is.
Everything makes sense in someone's mind.
Ya can't fix stupid.

Richard Deeming14-Jun-20 23:44

DataContext.GetCommand(IQueryable) Method (System.Data.Linq) | Microsoft Docs[^]
DataContext.Translate Method (System.Data.Linq) | Microsoft Docs[^]

14-Jun-20 23:44

As Stephen said in the blog post, Task.Run is equivalent to:

Task.Factory.StartNew(someAction, CancellationToken.None, TaskCreationOptions.DenyChildAttach, TaskScheduler.Default);

It is possible to get proper async support in LINQ to SQL, although it's not perfect. For example:

public static async Task<List<T>> ToListAsync(this IQueryable<T> query, DbContext context, CancellationToken cancellationToken = default)
{
    if (query is null) throw new ArgumentNullException(nameof(query));
    if (context is null) throw new ArgumentNullException(nameof(context));
    
    using (var command = (SqlCommand)context.GetCommand(query))
    {
        await command.Connection.OpenAsync(cancellationToken);
        
        using (var reader = await command.ExecuteReaderAsync(CommandBehavior.CloseConnection, cancellationToken))
        {
            return _context.Translate<T>(reader).ToList();
        }
    }
}

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

Kevin Marois15-Jun-20 7:31

15-Jun-20 7:31

Richard Deeming wrote:
using (var reader = await command.ExecuteReaderAsync(CommandBehavior.CloseConnection, cancellationToken))
{
return _context.Translate<T>(reader).ToList();
}

OK, so I'm using Linq to SQL. What more can I do to make the method async? The Command has the ExecuteReaderAsync method, but my Linq to SQL code won't have any of that. For example:

public Task<List<ReportData>> GetReportData(ReportArgsEntity args)
{
    var t = Task.Run(() => 
    {
        var results = new List<ReportData>();

        using (var dc = GetDataContecxt())
        {
            results = (from c in dc.Companies
                        join ih in dc.InvoiceHeaders on c.Id equals ih.CustomerId
                        join id in dc.InvoiceDetails on ih.Id equals id.HeaderId
                        where c.Completed
                        select new ReportData
                        {
                            // Add data to properties here
                        }).ToList();
        }

        return results;
    });

    return t;
}

If it's not broken, fix it until it is.
Everything makes sense in someone's mind.
Ya can't fix stupid.

Richard Deeming15-Jun-20 7:38

15-Jun-20 7:38

Use the extension method from my previous post. For example:

public async Task<List<ReportData>> GetReportData(ReportArgsEntity args)
{
    // Move the execution off the UI thread:
    await Task.Yield().ConfigureAwait(false);
    
    var query = from c in dc.Companies
                join ih in dc.InvoiceHeaders on c.Id equals ih.CustomerId
                join id in dc.InvoiceDetails on ih.Id equals id.HeaderId
                where c.Completed
                select new ReportData
                {
                    // Add data to properties here
                };
    
    return await query.ToListAsync(dc);
}

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

Kevin Marois15-Jun-20 7:41

15-Jun-20 7:41

I see.

The whole reason I'm asking is that right now all of the code is on the UI thread. But we're going to be moving the BL & DAL to Controllers in an ASP.Net Web API. So the UI will need to fire & forget each call and await the results.

Given that, and other that what we've already discussed, any reason this wouldn't work?

If it's not broken, fix it until it is.
Everything makes sense in someone's mind.
Ya can't fix stupid.

Richard Deeming15-Jun-20 7:50

15-Jun-20 7:50

The Web API action can be async, so this code will just work as-is. You might want to drop the Task.Yield line though, since you're not worried about blocking the UI thread.

The client code can make async requests to the web API - how easy that is will depend on which library you're using to call it. Using async and await will ensure that the UI thread isn't blocked whilst you're waiting for a response from the network.

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

Kevin Marois15-Jun-20 9:01

Removing a field from jSon String

15-Jun-20 9:01

Thanks Richard

If it's not broken, fix it until it is.
Everything makes sense in someone's mind.
Ya can't fix stupid.

simpledeveloper11-Jun-20 8:00

simpledeveloper

11-Jun-20 8:00

I am storing jSon string as hexa-decimal or some characters string, its all working fine whan I retrieving as json string in my code, but there is one field I want to remove from the jSob object after I retrieved.

var t = StoredProcedures.SP_GlobalSearch.Execute(new SP_GlobalSearch_Params
                        {
                            Search = request.search,
                            SourceKey = "",
                            Skip = start,
                            Take = length,
                            ShowDeleted = false
                        }).Select(x => new SP_GlobalSearch
                        {
                            JsonObject = x.Data != null ? new JavaScriptSerializer().DeserializeObject(x.Data.Replace("ï»¿", "")) : null,
                            Date = x.Date,
                            JsonObjectId = x.JsonObjectId,
                            SourceKey = x.SourceKey,
                            SourceId = x.SourceId,
                            TotalCount = x.TotalCount
                        });
                                           
                        var response = t?.ToList();
    
                        var jsondata = new DataTableResponse<SP_GlobalSearch>
                        {
                            totalCount = (int)response.Where(x => x.TotalCount != null).FirstOrDefault().TotalCount,
                            data = response.Where(x => x.TotalCount == null)
                        };
                       
                        var jsonResult = Json(jsondata);
                        jsonResult.MaxJsonLength = Int32.MaxValue;
                        return jsonResult;

I am reading the text as jSon with the below statement,

JavaScriptSerializer().DeserializeObject(x.Data.Replace("ï»¿", ""))

I want to remove the violations field from it, any help please. Thanks in advance

Here is my json:

{
   "InspectionResultId":846,
   "InspectionResultNumber":"T00846",
   "InspectionRequestId":507,
   "InspectionRequestNumber":"R00507",
   "CaseId":689,
   "InspectionResultStatusId":605,
   "EnforcementSectionId":104,
   "ViolationTypeId":603,
   "DateOfInspection":"\/Date(1589439600000)\/",
   "InspectionComment":"send to office staff, open investigation",
   "InspectedCompanyDataId":964,
   "ContactTypeId":701,
   "EnteredById":"7f54fa3e-b5cd-4b2e-9490-92f64c022246",
   "InspectionResultTimestamp":"\/Date(1588280817470)\/",
   "DateCreated":"\/Date(1588280817487)\/",
   "DateUpdated":"\/Date(1588281867967)\/",
   "CreatedByUserId":"7f54fa3e-b5cd-4b2e-9490-92f64c022246",
   "UpdatedByUserId":"7f54fa3e-b5cd-4b2e-9490-92f64c022246",
   "Case":{
      "RelatedContactId":0,
      "CaseId":689,
      "CaseNumber":"I00689",
      "IsInvestigation":true,
      "CaseStatusId":801,
      "InspectionItemSourceId":211,
      "EnforcementSectionId":104,
      "ReminderDate":"\/Date(1590044400000)\/",
      "PreCaseSummary":"send to office staff, open investigation",
      "AssignedToInspectorId":"7f54fa3e-b5cd-4b2e-9490-92f64c022246",
      "CaseTimestamp":"\/Date(1588281867403)\/",
      "CaseCompanyId":964,
      "DateCreated":"\/Date(1588281867437)\/",
      "DateUpdated":"\/Date(1588281867840)\/",
      "CreatedByUserId":"7f54fa3e-b5cd-4b2e-9490-92f64c022246",
      "UpdatedByUserId":"7f54fa3e-b5cd-4b2e-9490-92f64c022246",
      "IsDeleted":false,
      "InterpreterNeeded":false,
      "VoluntaryDisclosure":false,
      "PenaltyAdjustment":0,
      "Company":{
         "ContactId":964,
         "ContactTypeId":1000,
         "FirstName":"04.30.2020 new co",
         "Notes":"new request",
         "Active":true,
         "Created":"\/Date(1588279909680)\/",
         "Updated":"\/Date(1588279909680)\/",
         "DateCreated":"\/Date(1588279909680)\/",
         "DateUpdated":"\/Date(1588279909680)\/",
         "IsEJArea":false,
         "CreatedByUserId":"7f54fa3e-b5cd-4b2e-9490-92f64c022246",
         "UpdatedByUserId":"7f54fa3e-b5cd-4b2e-9490-92f64c022246",
         "Classification":{

         },
         "Class":"Company",
         "IsSpecial":false,
         "Address":{
            "Street1":"5678 Street",
            "City":"Sacramento",
            "StateCode":"CA",
            "Zip":"95812",
            "Country":"0"
         }
      }
   },
   "InspectionResultStatus":{
      "InspectionResultStatusId":605,
      "InspectionResultStatusName":"Clean",
      "InspectionResultStatusSortOrder":5
   },
   "EnforcementSection":{
      "EnforcementSectionId":104,
      "EnforcementSectionName":"STBES",
      "EnforcementSectionSortOrder":0,
      "BranchId":2
   },
   "InspectedCompanyData":{
      "ContactId":964,
      "ContactTypeId":1000,
      "FirstName":"04.30.2020 new co",
      "Notes":"new request",
      "Active":true,
      "Created":"\/Date(1588279909680)\/",
      "Updated":"\/Date(1588279909680)\/",
      "DateCreated":"\/Date(1588279909680)\/",
      "DateUpdated":"\/Date(1588279909680)\/",
      "IsEJArea":false,
      "CreatedByUserId":"7f54fa3e-b5cd-4b2e-9490-92f64c022246",
      "UpdatedByUserId":"7f54fa3e-b5cd-4b2e-9490-92f64c022246",
      "Classification":{

      },
      "Class":"Company",
      "IsSpecial":false
   },
   "InspectionItems":[
      {
         "InspectionItemId":1054,
         "InspectionItemNumber":"T00000",
         "InspectionRequestId":507,
         "InspectionResultId":846,
         "CaseId":689,
         "InspectionItemSourceId":229,
         "IsCreatedInCase":false,
         "ShowYearMakeModel":"",
         "ShowYearMakeModelVIN":"",
         "GrossWeight":0.00,
         "RegHoldSet":false,
         "InspectionItemTimestamp":"\/Date(1588280802553)\/",
         "DateCreated":"\/Date(1588280802567)\/",
         "DateUpdated":"\/Date(1588281868153)\/",
         "CreatedByUserId":"7f54fa3e-b5cd-4b2e-9490-92f64c022246",
         "UpdatedByUserId":"7f54fa3e-b5cd-4b2e-9490-92f64c022246",
         "Violations":[

         ]
      }
   ],
   "CompletedBy":[
      {
         "IsActive":true,
         "FirstName":"Daphne",
         "LastName":"Greene",
         "ObjectGUID":"S-1-5-21-1538631513-416410304-3002070310-33442",
         "NameLoginFormat":"dgreene",
         "NameFirstLast":"Daphne Greene",
         "NameLastFirst":"Greene Daphne",
         "Email":"daphne.greene@arb.ca.gov",
         "EmailConfirmed":false,
         "SecurityStamp":"e061e77e-c93e-4b9e-8497-4852b5cb4ca2",
         "PhoneNumberConfirmed":false,
         "TwoFactorEnabled":false,
         "LockoutEnabled":false,
         "AccessFailedCount":0,
         "Id":"7f54fa3e-b5cd-4b2e-9490-92f64c022246",
         "UserName":"dgreene"
      }
   ],
   "EnteredBy":{
      "IsActive":true,
      "FirstName":"Daphne",
      "LastName":"Greene",
      "ObjectGUID":"S-1-5-21-1538631513-416410304-3002070310-33442",
      "NameLoginFormat":"dgreene",
      "NameFirstLast":"Daphne Greene",
      "NameLastFirst":"Greene Daphne",
      "Email":"daphne.greene@arb.ca.gov",
      "EmailConfirmed":false,
      "SecurityStamp":"e061e77e-c93e-4b9e-8497-4852b5cb4ca2",
      "PhoneNumberConfirmed":false,
      "TwoFactorEnabled":false,
      "LockoutEnabled":false,
      "AccessFailedCount":0,
      "Id":"7f54fa3e-b5cd-4b2e-9490-92f64c022246",
      "UserName":"dgreene"
   },
   "MyGridContacts":[

   ],
   "CreatedByUser":{
      "IsActive":true,
      "FirstName":"Daphne",
      "LastName":"Greene",
      "ObjectGUID":"S-1-5-21-1538631513-416410304-3002070310-33442",
      "NameLoginFormat":"dgreene",
      "NameFirstLast":"Daphne Greene",
      "NameLastFirst":"Greene Daphne",
      "Email":"daphne.greene@arb.ca.gov",
      "EmailConfirmed":false,
      "SecurityStamp":"e061e77e-c93e-4b9e-8497-4852b5cb4ca2",
      "PhoneNumberConfirmed":false,
      "TwoFactorEnabled":false,
      "LockoutEnabled":false,
      "AccessFailedCount":0,
      "Id":"7f54fa3e-b5cd-4b2e-9490-92f64c022246",
      "UserName":"dgreene"
   },
   "UpdatedByUser":{
      "IsActive":true,
      "FirstName":"Daphne",
      "LastName":"Greene",
      "ObjectGUID":"S-1-5-21-1538631513-416410304-3002070310-33442",
      "NameLoginFormat":"dgreene",
      "NameFirstLast":"Daphne Greene",
      "NameLastFirst":"Greene Daphne",
      "Email":"daphne.greene@arb.ca.gov",
      "EmailConfirmed":false,
      "SecurityStamp":"e061e77e-c93e-4b9e-8497-4852b5cb4ca2",
      "PhoneNumberConfirmed":false,
      "TwoFactorEnabled":false,
      "LockoutEnabled":false,
      "AccessFailedCount":0,
      "Id":"7f54fa3e-b5cd-4b2e-9490-92f64c022246",
      "UserName":"dgreene"
   }
}

I want to remove the Violations part from the jSon object, can you please help me in this regards thank you.

modified 11-Jun-20 18:08pm.

OriginalGriff11-Jun-20 22:44

OriginalGriff

11-Jun-20 22:44

You can't "remove" the violations from the JSON once you have read it: either it's still in the JSON string (in which case you probably want to look at a Regex or similar to remove fit from that) or it's a part of the InspectionItem class and the best you can do is set the InspectionItem.Violations property to null for each instance in your data.
You can't "delete" a property from a class after compilation!

Probably the best way would be to use a Regex to remove the Violations section from the JSON source before you deserialize it - but there could be some significant work involved in writing that, given that the sample you show does not contain any data in the Violations section, so we have no idea how complicated that JSON clause might be when filled in. Complicated clause == complicated Regex! Laugh | :laugh:

"I have no idea what I did, but I'm taking full credit for it." - ThisOldTony
AntiTwitter: @DalekDave is now a follower!

simpledeveloper12-Jun-20 9:05

simpledeveloper

12-Jun-20 9:05

Yeah making that property value null is fine - can you please help me in this regards please? Or can you please help me with the Regex please? Thank you.

OriginalGriff12-Jun-20 9:06

OriginalGriff

12-Jun-20 9:06

You don't know how to set a property?

Why are you playing with JSON if you don't know the (very, very) basics?

"I have no idea what I did, but I'm taking full credit for it." - ThisOldTony
AntiTwitter: @DalekDave is now a follower!