I'm using EF version 4.1, and would like to have the data from the database in realtime, i.e. if you open the application it detects if there is new data in the database, and update the above it! is It possible to do this? I am using EF 4.1 code first time
View 1 RepliesHow to update the existing Customer object, Insert new Computer object and Add new WorkOrder using entity framework? [code]
View 2 Repliesc# - Are Microsoft Entity Framework and ADO.NET Entity Framework (.edmx) the same?
View 7 RepliesI am used to using datasets for my projects in terms of data access. I now set myself an easy app to work on in order to learn the entity data framework and how to retrieve & manipulate data.Can anyone guide me through on where to start, what are the advantages of this model, In what scenarios should I choose to use entity framework and what are the things (basis) I should now before starting.My datasets are working fine too. Are there any reasons for me not to stick with that way of accessing data? Or is this something to consider depending on the users of the website (for speed purposes etc.)
View 3 RepliesI am having trouble getting the new Entity Framework's objects and classes to store data in my database. I have tried basically everything I can think of, asked for various forums with no success, and I am starting to wonder if the new EF is merely for reading data and not saving it. Now, I decided to make atest Console application to make a single record in the database. The code is quite simple:
Sub
Main()
Dim ent As New MyModelEntities()
[code].....
I have a view on some data in my database it returns the data as I would expect, for example
Call Date To From Phone Number
20/1/2010 00:00 23:59 08923233223
20/1/2010 00:00 23:59 08923233245
However when I have added this to my Entity Model and query it I get duplicate(and unexpected) data appearing
Call Date To From Phone Number
20/1/2010 00:00 23:59 08923233223
20/1/2010 00:00 23:59 08923233223
I am simply binding a Entity Data Source to this Entity but I am left scratching my head as to why the data is being returned differently
EDIT: Interestingly this can't be the result of some strange under the hood join as the row counts match as expected. I have also put together a query myself to test with the same odd results.From o In App.Entities.v_PersonalRules Where o.companyid = CompanyID Select o. I am using Visual Studio 2010, .NET 4
EDIT: The front end code is fairly simple
<asp:EntityDataSource ID="EDS_Personal" runat="server" ConnectionString="name=Entities_NEW"
DefaultContainerName="Entities_NEW" EnableDelete="True" EnableInsert="False"
EnableUpdate="True" EntitySetName="v_PersonalRules" EntityTypeFilter="v_PersonalRules" >[code]....
I have a WCF Windows service that provides data to 250+ PDAs via compressed datasets and was looking to redevelop both the service and the mobile application to use Entity Framework 4.x models. In order to keep performance acceptable when sending/receiving data on the PDA I need to keep the data size as small as possible and was wondering if its possible to compress a IEnumerable from the WCF windows service? From previous experience with the datasets I got a 80%+/- compression rate and even decompressing the data on the PDA achieved an overal 50% performance importment so retaining similar levels of performance is critical. Could I use a binary serializer and then compress the stream?
View 1 RepliesThis is my function:
Public Function GetAllEmployee() As List(Of Employees)
Return DB.Employees.Select(Function(q) New With {q.EmployeeID, q.LastName,q.FirstName}).ToList()
End Function
I'm getting an error:
Value of type System.Collections.Generic.List(Of <anonymous type>) cannot be converted to System.Collections.Generic.List(Of NorthwindModel.Employees).
I'm taking a peek at both the Entity Framework and LINQ to SQL, and while I like the systems (and of course the LINQ integration) I'm a little skeptical on the data-binding aspect. I've taken query results and inspected them, and they don't appear to implement the standard .NET list-binding interfaces (IBindingList, and more importantly ITypedList), leading me to believe that binding them to a grid (or anything else) is going to use reflection to get/set my entity properties. This seems like a comparatively expensive operation, especially when all of the code is generated anyway and could implement the interfaces. Is reflection used to get/set the value of the properties?
Edit: I'm actually concentrating on whether or not ITypedList is implemented somewhere along the way, as that's what has the capability to provide an explicit mechanism for defining and interacting with properties without resorting to reflection. While I didn't have a LINQ to SQL project up,I did inspect a simple Entity Framework entity query result, and it did not appear to implement ITypedList.
Edit 2: After accepting Marc's answer, I thought it might be helpful for others if I posted some simple code I used to seamlessly implement his solution. I put the following in the static constructor for my class:
public static ContextName()
{
foreach(Type type in System.Reflection.Assembly.GetExecutingAssembly()[code]....
While this is for LINQ to SQL, I'm sure an equivalent version could be written for the Entity Framework. This will scan the assembly for any types with the Table attribute and add a custom provider for each of them.
I have a the following setup
m_handsets = From p In RL.App.TComEntities.tblTelephoneNumbers _
Where p.companyId = m_CompanyID _
Select p
m_handsets = DirectCast(m_handsets, ObjectQuery(Of RL.TelephoneNumbers)).Include("tblCalls")
where m_handsets is defined as Private m_handsets As IQueryable(Of RL.tblTelephoneNumbers)
which works as expected however what I want to do know is query the Navigation property (tblCalls) so I can do something like the following From p In m_handsets.tblCalls Where m_handsets.tblCalls.price > 100
I think the complexity comes here because in this instance I could have 5 tblTelephoneNumbers in m_handsets and then x amount of calls for that particular telephone number. I am interested in the tblCalls for each but I would like to filter them all for each tblTelehoneNumber.
Entity Diagram which (hopefully) should illustrate further So I currently know all the handsets that are associated with the company I am interested in. I can also see the calls loaded as a navigation property in debug mode, but I want to say is take this filter (in this example price>100 and apply it to all handsets->calls
I want to update an entity without loading the entity from the database first. I've accomplished this but only by knowing all of the entities properties and then using the "attachto" method. My issues is i don't want my app to need to remember all of the properties. Example:
[Code]....
Entity Splitting: one class, two or more tables.Here is how it is done in C#, but I need to get it working in vb.net.One more thing: the class name and table columns do not match, so I have to be able to map that out, too.I have to get this to work this way because the place I'm working at right now is a vb.net only shop and the database schema is fubar, but they have so much (millions) of lines of code done directly against the database in both asp classic, vb.net, AND asp.net webforms that changing the schema right now is not realistically possible.
protected override void OnModelCreating(DbModelBuilder modelBuilder)
{
modelBuilder.Entity<Post>()
.Map(m =>
[code]....
I am trying to jump from ASP Classic to asp.net. I have followed tutorials to get Entity Framework and LINQ to connect to my test database, but I am having difficulties figuring out ExecuteQuery(). I believe the problem is that I need an "entity class" for my database, but I can't figure out how to do it. Here is my simple code:
Dim db as New TestModel.TestEntity
Dim results AS IEnumerable(OF ???) = db.ExecuteQuery(Of ???)("Select * from Table1")
From the microsoft example site, they use an entity class called Customers, but I don't understand what that means.
I'm working on a windows forms application (.NET 4.0).My form contains a 'Fast Line' chart using the Microsoft chart control included in VS2010.The chart gets filled with about 20,000 datapoints.My application then starts receiving market data from a server via DDE (Dynamic Data Exchange) in real-time and adds it the chart.
View 5 RepliesI have to send a sequence of video frames over UDP as fast and real-time as possible and while I got the basics working, I am running into all sorts of difficulties. Some of my goals:Data will normally be sent over dial-up (hence UDP instead of TCP), but also needs to support fast Ethernet.It's OK to occasionally drop frames (hence UDP instead of TCP).Need low latency. The frame the remote receives should be one that was recently sent (no more than a few frames waiting in buffers).I need to be able to detect the effective bandwidth so that I can compress the frames more or less to keep frame rate up.I break up frame data into one or more datagrams of about 500 bytes and each has a sequence number and other info. The receiver reassembles the entire frame and detects if any datagrams are missing.If the receiver detects more than a certain percentage of dropped frames (e.g. 50% over the last 10 frames), I send a TCP message to the sender to slow down by 50%. Sender than slowly increases speed by 5% each subsequent frame.Using System.Net.Sockets.UdpClient to send and receive the data.I have a separate TCP channel used for control messages back to sender.My main difficulty right now is detecting the effective bandwidth and dealing with latency, especially over dial-up (max ~4,000 bytes/sec). For example, if I try to send 100,000 bytes/second using TcpClient.Send() they ALL seem to arrive (no dropped datagrams) but with large latency by the time last datagram arrives. I think the TcpClient.Send() function is blocking until the buffer is able to send which messes up my current algorithm.
Can anybody point me to any sources of information for how to:Detect actual bandwidth over UDP.A better algorithm for dynamically adjusting bandwidth to suit the available pipe.Send data smoothly at the desired bandwidth.A way to detect and keep latency down to a minimum.I have been spinning my wheels over the last week and every time I solve one problem it seems another rears up is head.
are there any ways that i can extract my data from database and display it into my listbox in real-time? which means that whatever is updated in my database must immediately be inserted into the listbox without the need of refreshing or pressing any buttons. Immediate display.
View 3 Repliesmethods/procedures for sending real time data from a VB.net app to a web server (asp.net) for real time display. My question relates to the best method to send the data from the desktop app and the best way to receive and handle the data on the server. I'm not asking for sample code, just some idea of what methods to research. I am currently using a text file upload method but I'm sure there is a more efficient way of achieving this.
View 2 RepliesI have been trying to find and/or think up a way for data to automatically update a data table.I have a log that shows all the customers that came in today with various information. There could be twenty or thirty employees adding to this log or updating or doing things with that customer. This information is in a Data Table on a ASPX page in Visual Studio 2010 that the code is binded in the aspx.vb page that is calling a page in my APP_CODE database file that calls a query in my Database to get the information.My question is could someones actions on a different computer make my computer refresh or to re-bind that data.I have thought of some kind of timer/counter maybe that looks to see if the count of the log is different.
View 2 Repliesi have a program that function as a DAQ System.i have input channel to gather information from sensors. The reading of each sensor such as voltage, current and temperature are displayed in the textbook. As we all know, DAQ system is involve taking data real-time measurement.My problem is:
1. how to update each row automatically as time goes on. the value in the textbook is updated by each second.Below figure shows how the excel can be written automatically row by row, as time ticking for a sec. this update will stop as the timer stop.
I have a driver for the device and I already have it integrated into an application.
It is a Human Input Device with buttons.
Controlling the device is not the issue nor is receiving button presses.
I want to retrieve the actual data that is being sent from the device to the computer and from the computer to the device.
I have seen a lot of hardware approaches but not any software approaches(that work right).
Basically I have a program that receives real time data from microcontroller and displays it in a text box. What I would now like to do is to store the values received into a table that can be viewed when the receive program finishes. However I still want the values displayed as they are received in addition to being stored in a table of some sort.
View 3 RepliesI'm having a bit of an issue receiving a stream of serial data and displaying the data real-time in my GUI. I am fairly new to VB.Here's what I'm trying to achieve: I have an I2C device (bank of LED's) connected to my Arduino. Using the VB.NET (2010) GUI I request which LED I want on (via buttons) and the I2C device then sends a reply confirming which LED actually turned on (basic feedback). Ok, sounds great right? Here's where I get issues. Well when I try to read the serial data sent to VB and display the real-time stream on the GUI, a) I get a bit of a mess as an output (values are ok, just spewn across GUI) and b) when I select a new LED to turn on, the GUI data does not refresh to this change. The stream being sent from the Arduino is ok, I looked at the data in a serial monitor.
[Code]...
I've use VB net to create a application that can download the real-time data from a device for every second. Now I want to upload the data to a website in real time. (So some who is far away, can also check the data through the website)
View 3 RepliesHBasically I will have two forms. Form1 will control form2 which is the media display. Form2 will give back the media status and info back to form1 in someway. I was thinking of creating properties in form2 and having form1 polling these values to display the elapse run time etc... ideally i wish to have form2 somehow send events back with data when it values gets updated.
View 1 RepliesI am working on a project that is able to display real time data from sensors from micro-controller. I am able to do so by sending the data through the serial port and then use vb 2005 to show the data. However, I want to save those data from vb 2005 to excel. How am I able to do it ? I am able to use vb to insert data to excel step by step, cell by cell using the following codes.
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
Dim oExcel As Object
Dim oBook As Object
Dim oSheet As Object
[code]....
Lets say TextBox1.Text and TextBox2.Text is my real time data. How do I save it to the excel sheet displaying the data in cell A2, A3, A4 when the time goes by. Eg. If I want to save TextBox1.Text to excel it would be, the data in the 1st seconds in cell A2, data in the 2nd seconds in A3, 3rd seconds A4, 4th seconds in A5, A6 and so on...
On VB.NET 2005 and 2008, if you were debugging you could roll over the variable you set as an array and a little "+" would pop up next to the array variable and you could click it and see all of the data loaded into the array.
View 3 Repliesconnected to my Arduino. Using the VB.NET (2010) GUI I request which LED I want on (via buttons) and the I2C device then sends a reply confirming which LED actually turned on (basic feedback). Ok, sounds great right? Here's where I get issues. Well when I try to read the serial data sent to VB and display the real-time stream on the GUI, a) I get a bit of a mess as an output (values are ok, just spewn across GUI) and b) when I select a new LED to turn on, the GUI data does not refresh to this change. The stream being sent from the Arduino is ok, I looked at the data in a serial monitor.
Public Class Form1
Dim ticktock As Integer
Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles
[code].....
I am busy with a VB2008 EXPRESS program that reads is data via a network cable. Saving the data on the same computer as my program is not a problem, but I must also make this data available to other users in the network and update their screens in real time. In other words I need a COPY of my running program on each networked computer when requested by the user in the network. I have looked at SQL, XML pages and inheritance. But I am confused, what is the best way???
View 13 RepliesI m into automation development of FMCG products using Micro-controllers. I get real time data Barcode 2D from TCP/IP connection. My task is to compare the result do some Computation with them and Store the incoming Barcode and results into a Excel sheet in a folder. I m successful with the basic working. Am currently working at slow speed of 1 barcode(22 char info) per second from the TCP/IP data (barcode scanner). Now, comes the real issue. I need to process atleast 5 barcodes per sec ( <200ms per process). I m partially successful with 3 Barcode per second(300 ms per process). so, thats like 300ms per processing. I need to achieve less than 200ms for entire processing. I have used threads and timers. but I m unable to achieve. Seems like storing in Excel takes more than 250ms. Since i come from micro controllers background 1msec is a lotta time to process for me. I m not sure how much time does it take and trust me i find it difficult to guage the time here.
View 1 Replies- I'm working on a windows forms application (.NET 4.0). - My form contains a 'Fast Line' chart using the Microsoft chart control included in VS2010. - The chart gets filled with about 20,000 datapoints. - My application then starts receiving market data from a server via DDE (Dynamic Data Exchange) in real-time and adds it the chart.
Note: I have no control over the server and so I have to deal with DDE only even though it's an outdated technology. VS doesn't support DDE anymore and so I use the Ndde library which works like a charm.
Private Sub StartDDE()
'first we connect to the DDE server:
Dim client As DdeClient = New DdeClient("ServerApplication", "Bid")
[Code].....