cdotlister - Developer IT

Design question for WinForms (C#) app, using Entity Framework

- by cdotlister

I am planning on writing a small home budget application for myself, as a learning excercise. I have built my database (SQL Server), and written a small console application to interact with it, and test out scenarios on my database. Once I am happy, my next step would be to start building the application - but I am already wondering what the best/standard design would be. I am palnning on using Entity Framework for handling my database entities... then linq to sql/objects for getting the data, all running under a WinForms (for now) application. My plan (I've never used EF... and most of my development background is Web apps) is to have my database... with Entity Framework in it's own project.. which has the connection to the database. This project would expose methods such as 'GetAccount()', 'GetAccount(int accountId)' etc. I'd then have a service project that references my EF project. And on top of that, my GUI project, which makes the calls to my service project. But I am stuck. Lets say I have a screen that displays a list of Account types (Debit, Credit, Loan...). Once I have selected one, the next drop down shows a list of accounts I have that suite that account type. So, my OnChange event on my DropDown on the account type control will make a call to the serviceLayer project, 'GetAccountTypes()', and I would expect back a List< of Account Types. However, the AccountType object ... what is that? That can't be the AccountType object from my EF project, as my GUI project doesn't have reference to it. Would I have to have some sort of Shared Library, shared between my GUI and my Service project, with a custom built AccountType object? The GUI can then expect back a list of these. So my service layer would have a method: public List<AccountType> GetAccountTypes() That would then make a call to a custom method in my EF project, which would probably be the same as the above method, except, it returns an list of EF.Data.AccountType (The Entity Framework generated Account Type object). The method would then have the linq code to get the data as I want it. Then my service layer will get that object, and transform it unto my custom AccountType object, and return it to the GUI. Does that sound at all like a good plan?

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Looking for best practise for writing a serial device communication app in C#

- by cdotlister

I am pretty new to serial comms, but would like advise on how to best achieve a robust application which speak to and listens to a serial device. I have managed to make use of System.IO.serialport, and successfully connected to, sent data to and recieved from my device. The way things work is this. My application connects to the Com Port and opens the port.... I then connect my device to the com port, and it detects a connectio to the PC, so sends a bit of text. it's really just copyright info, as well as the version of the firmware. I don't do anything with that, except display it in my 'activity' window. The device then waits. I can then query information, but sending a command such as 'QUERY PARAMETER1'. It then replies with something like: 'QUERY PARAMETER1\r\n\r\n76767\r\n\r\n' I then process that. I can then update it by sending 'SET PARAMETER1 12345', and it will reply with 'QUERY PARAMETER1\r\n\r\n12345\r\n\r\n'. All pretty basic. So, what I have done is created a Communication Class. this call is called in it's own thread, and sends data back to the main form... and also allows me to send messages to it. Sending data is easy. Recieving is a bit more tricky. I have employed the use of the datarecieved event, and when ever data comes in, I echo that to my screen. My problem is this: When I send a command, I feel I am being very dodgy in my handling. What I am doing is, lets say I am sending 'QUERY PARAMETER1'. I send the command to the device, I then put 'PARAMETER1' into a global variable, and I do a Thread.Sleep(100). On the data recieved, I then have a bit of logic that checks the incoming data, and sees if the string CONTAINS the value in the gloabl variable. As the reply may be 'QUERY PARAMETER1\r\n\r\n76767\r\n\r\n', it sees that it contains my parameter, parses the string, and returns the value I am looking for, but placing it into another global variable. My sending method was sleeping for 100ms. It then wakes, and checks the returned global variable. If it has data... then I'm happy, and I process the data. Problem is... if the sleep is too short.. it will fail. And I feel it's flakey.. putting stuff into variables.. then waiting... The other option is to use ReadLine instead, but that's very blocking. So I remove the datarecieved method, and instead... just send the data... then call ReadLine(). That may give me better results. There's no time, except when we connect initially, that data comes from the device, without me requesting it. So, maybe readline will be simpler and safer? Is this known as 'Blocking' reads? Also, can I set a timeout? Hopefully someone can guide me.

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Linq and returning types

- by cdotlister

My GUI is calling a service project that does some linq work, and returns data to my GUI. However, I am battling with the return type of the method. After some reading, I have this as my method: public static IEnumerable GetDetailedAccounts() { IEnumerable accounts = (from a in Db.accounts join i in Db.financial_institution on a.financial_institution.financial_institution_id equals i.financial_institution_id join acct in Db.z_account_type on a.z_account_type.account_type_id equals acct.account_type_id orderby i.name select new {account_id = a.account_id, name = i.name, description = acct.description}); return accounts; } However, my caller is battling a bit. I think I am screwing up the return type, or not handling the caller well, but it's not working as I'd hoped. This is how I am attempting to call the method from my GUI. IEnumerable accounts = Data.AccountService.GetDetailedAccounts(); Console.ForegroundColor = ConsoleColor.Green; Console.WriteLine("Accounts:"); Console.ForegroundColor = ConsoleColor.White; foreach (var acc in accounts) { Console.WriteLine(string.Format("{0:00} {1}", acc.account_id, acc.name + " " + acc.description)); } int accountid = WaitForKey(); However, my foreach, and the acc - isn't working. acc doesn't know about the name, description and id that I setup in the method. Am I at least close to being right?

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Looking for best practise for writing a serial device communication app

- by cdotlister

I am pretty new to serial comms, but would like advise on how to best achieve a robust application which speak to and listens to a serial device. I have managed to make use of System.IO.SerialPort, and successfully connected to, sent data to and recieved from my device. The way things work is this. My application connects to the Com Port and opens the port.... I then connect my device to the com port, and it detects a connection to the PC, so sends a bit of text. it's really just copyright info, as well as the version of the firmware. I don't do anything with that, except display it in my 'activity' window. The device then waits. I can then query information, but sending a command such as 'QUERY PARAMETER1'. It then replies with something like: 'QUERY PARAMETER1\r\n\r\n76767\r\n\r\n' I then process that. I can then update it by sending 'SET PARAMETER1 12345', and it will reply with 'QUERY PARAMETER1\r\n\r\n12345\r\n\r\n'. All pretty basic. So, what I have done is created a Communication Class. this call is called in it's own thread, and sends data back to the main form... and also allows me to send messages to it. Sending data is easy. Recieving is a bit more tricky. I have employed the use of the datarecieved event, and when ever data comes in, I echo that to my screen. My problem is this: When I send a command, I feel I am being very dodgy in my handling. What I am doing is, lets say I am sending 'QUERY PARAMETER1'. I send the command to the device, I then put 'PARAMETER1' into a global variable, and I do a Thread.Sleep(100). On the data received, I then have a bit of logic that checks the incoming data, and sees if the string CONTAINS the value in the global variable. As the reply may be 'QUERY PARAMETER1\r\n\r\n76767\r\n\r\n', it sees that it contains my parameter, parses the string, and returns the value I am looking for, but placing it into another global variable. My sending method was sleeping for 100ms. It then wakes, and checks the returned global variable. If it has data... then I'm happy, and I process the data. Problem is... if the sleep is too short.. it will fail. And I feel it's flaky.. putting stuff into variables.. then waiting... The other option is to use ReadLine instead, but that's very blocking. So I remove the data received method, and instead... just send the data... then call ReadLine(). That may give me better results. There's no time, except when we connect initially, that data comes from the device, without me requesting it. So, maybe ReadLine will be simpler and safer? Is this known as 'Blocking' reads? Also, can I set a timeout? Hopefully someone can guide me.

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ASP.Net MVC - Models and User Controls

- by cdotlister

Hi guys, I have a View with a Master Page. The user control makes use of a Model: <%@ Control Language="C#" Inherits="System.Web.Mvc.ViewUserControl<BudgieMoneySite.Models.SiteUserLoginModel>" %> This user control is shown on all screens (Part of the Master Page). If the user is logged in, it shows a certain text, and if the user isn't logged in, it offers a login box. That is working OK. Now, I am adding my first functional screen. So I created a new view... and, well, i generated the basic view code for me when I selected the controller method, and said 'Create View'. My Controller has this code: public ActionResult Transactions() { List<AccountTransactionDetails> trans = GetTransactions(); return View(trans); } private List<AccountTransactionDetails> GetTransactions() { List<AccountTransactionDto> trans = Services.TransactionServices.GetTransactions(); List<AccountTransactionDetails> reply = new List<AccountTransactionDetails>(); foreach(var t in trans) { AccountTransactionDetails a = new AccountTransactionDetails(); foreach (var line in a.Transactions) { AccountTransactionLine l = new AccountTransactionLine(); l.Amount = line.Amount; l.SubCategory = line.SubCategory; l.SubCategoryId = line.SubCategoryId; a.Transactions.Add(l); } reply.Add(a); } return reply; } So, my view was generated with this: <%@ Page Language="C#" MasterPageFile="~/Views/Shared/Site.Master" Inherits="System.Web.Mvc.ViewPage<System.Collections.Generic.List<BudgieMoneySite.Models.AccountTransactionDetails>>" %> Found <%=Model.Count() % Transactions. All I want to show for now is the number of records I will be displaying. When I run it, I get an error: "The model item passed into the dictionary is of type 'System.Collections.Generic.List`1[BudgieMoneySite.Models.AccountTransactionDetails]', but this dictionary requires a model item of type 'BudgieMoneySite.Models.SiteUserLoginModel'." It looks like the user control is being rendered first, and as the Model from the controller is my List<, it's breaking! What am I doing wrong?

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CSS working in IE, but not FF

- by cdotlister

Hi guys, I have a very simple css file for my Asp.Net MVC application. body { font-family: Arial, Helvetica, sans-serif; font-size: x-small; color: #663300; } input { font-family: Arial, Helvetica, sans-serif; font-size: x-small; background-color: #FFFF99; color: #CC6600; border: 1px solid #808000; } .headerRow { background-color: #FFFFCC; border-style: none none dotted none; border-bottom-width: 1px; border-bottom-color: #800000; font-family: Arial, Helvetica, sans-serif; font-size: x-small; font-weight: bold; text-align: left; vertical-align: middle; text-transform: uppercase; } The Body is working well in both... as is the input. However, the headerRow isn't working in FF, yet works well in IE. Here it is, being used: <table width="700" border="0" cellspacing="1" cellpadding="2"> <tr class="headerRow"> <td> Transaction Date </td> <td> Type </td> <td> Category </td> <td> Budget Assignment </td> <td> Cost Center </td> <td align="right"> Amount </td> </tr> The header row just displays as normal body text though...

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