What Constraints Are In Application
Nov 1, 2009Can some one explain what constraints are in this application?
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Visual Studio 2010 - Failed To Enable Constraints - One Or More Rows Contain Values Violating Non-null - Unique - Or Foreign-key Constraints. Error
Dec 9, 2011There were three similar questions in StackOverFlow but none gave an answer.. If have found why this error in occurring but don't know the fix. I am using Strongly Typed Dataset for my project which is created as a dll for DAL. I have added the Sql Server Table into this dataset using the designer and has created a DataAdapter
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Asp.net - Enforcing Database Constraints In Application Code
Sep 16, 2011I'm working on my first real asp.net web application and I'm kind of stumped on the best place and method to trap and handle database constraint violations. Suppose I have a unique constraint on a column and a user inputs something that would violate that unique constraint. Do I catch it in the business layer by making a call to the database to check of the value exists for that column or do I let it go all the way to the database and let it throw an exception and handle that in my application?
I don't like the latter answer- because it makes sense to handle as much as you can in the business layer before it reaches the database. But it's also somewhat problematic as my application is driven by procedures that implement basic CRUD operations on all tables. So in order for me to enforce uniqueness in the business layer, I need to create a procedure for every possible constraint so I can do a look up before an update or insert. That just seems tedious... and I'm duplicating business rules as they exist in both the database and the business layer, so if something changes, not only do I have to change the database, but I have to change the procedure and the application code.
So is there a right way or a good way to enforce these database constraints in application code or should I be looking at a way to catch exceptions thrown by the database and present them in a user-friendly way?
Constraints On Generics With .Net?
Dec 14, 2011I have the a function that is declared like so: Public Sub Modify(Of SIMType As {New, DAOBase})(ByVal obj As SIMType)
I also have a class called Products which is declared like so:
Public Class Products Inherits DAOBase
So as you can see, if I were to call this function like so:
Modify(Of Products)(new Products())
This would not be an issue. The issue actually arises when I try to cast the object being past in to its real type. For example: both do not work. I get a Value of type SIMTYPE cannot be converted to IMS.Products error. Im assuming this is because I am using generics. Is there a way to adjust my function to allow for a casting operation like I am trying to do? In the end, what I need is a reference of the actual type (Products in this case) to the object.
.NET Generic Constraints And Subclasses?
Sep 17, 2010Consider the following extension method:
<Extension()> _
Public Function Satisfies(Of T)(ByVal subject As T, ByVal specification As ISpecification(Of T)) As Boolean
Return specification.IsSatisfiedBy(subject)
End Function
This works as expected if subject is the exact class being operated on by the specification. However, if the specification is examining the super-class of T, this extension will not work unless subject is explicitly cast to the super-class. Is there a way I can avoid this? So far, the best I've been able to come up with is:
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Since I (apparently) can't get this to work exactly as I'd like in VB.NET due to limitations in the language itself, is my second attempt the safest/most efficient way to do this?
.net - Extension Method And Type Constraints?
Sep 13, 2010I am starting to play with extension methods and i came across with this problem:In the next scenario i get a: "extension method has a type constraint that can never be satisfied"
Public Interface IKeyedObject(Of TKey As IEquatable(Of TKey))
ReadOnly Property InstanceKey() As TKey
End Interface
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.net - Getting The Foreign Key Constraints Of A Table Programmatically?
May 17, 2012I'm trying to use a DataTable to get the schema of a SQL Server DB.But, when try to detect the ForeignKeys, the constraints collection only brings the UNIQUE constraints.
Private Sub ShowConstraints(ByVal tableName As String)
Dim table As DataTable = New DataTable(tableName)
Using connection As SqlConnection = New SqlConnection(GetConnectionString)
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How can I get the ForeignKey Constraints?
Add Constraints To Image Resizing Code?
Feb 15, 2012How do I add constraints to image resizing code? I want the image to be no larger then 165x146. The below code does not hold the constraint when image is 525x610.[code]
View 1 RepliesFilter Data Based On Various Constraints
Feb 17, 2012I am doing a projectin VB 2008..I ave list of data being displayed in listview and it gets stored in DB..The problem is,i am unable to filter particular data based on some constraints like date,client etc.. How can i filter data based on various constraints..As i am new to VB,
View 5 RepliesGeneric Constraints That Allow Type To Be 2 Different Classes?
Mar 21, 2012I have a generic function in VB.Net. I also have two classes called A and B. Is it possible to allow the generic constraints on my function to allow the Type to be either class A or B? Class A and B do not share any base classes except for object.
View 1 RepliesDataSet Bound To DGV - Failed To Enable Constraints
Jul 31, 2010I keep getting this error message (see image). What's weird is it's coming from a "typed" dataset that is bound to a DataGridView and even though I get this message, the DGV still loads with all the data. I've bound this dataset to the DGV thru the designer. Here is the line of code that is erroring out:
Me.adpItemMaster.Fill(Me.JewelryDBDataSet18.tblItemMaster)
I checked the table and the primaryKey for the tblItemMaster is unique for each row.
Failed To Enable Constraints. DataAdapter.fill()?
Mar 29, 2009When I use the dataAdapter.fill(ds,tableName), it reports an error: "Failed to enable constraints."Yes, I changed the selectcommand.I know if I modified the selectcommand, and if it will take diffrent columns result, this error will be reported.
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Use Generic Constraints Based On Attributes Rather Than Types?
Aug 28, 2009I'm trying to write a class that will be in charge of persisting application options. Since the options need to be persisted the values that I'm sent must be serialisable.
Initially I thought I've be able to write a method with a signature like this[code]...
Error Message "Failed To Enable Constraints
Sep 11, 2009I am getting headache analyzing what's causing this error message "Failed to enable constraints. One or more rows contain values violating non-null, unique, or foreign-key constraints."I have 7 different sections, each sections has the same subject component, one of which is CLUB. The error will only display for one particular section but for the rest of the sections, the program work fine. All sections uses the same code that's why I am very puzzled with the error. if the code works for the rest of the section one it fails for the one particular section?I have check my table (sql2005 express) and all the records are intact.The error is pointing on da.Fill(Me.Grading_Rpt_DataSet.tblEnrol)of the code below.
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Specifying Inherits / Implements On Generic Class With Multi-Constraints
Jun 7, 2010When I write the following statement in VB.Net (C# is my normal language), I get an "end of statement expected" referring to the "Implements" statement.
<Serializable()> _
<XmlSchemaProvider("EtgSchema")> _
Public Class SerializeableEntity(Of T As {Class, ISerializable, New}) _
Implements IXmlSerializable, ISerializable
...
End Class
The C# version that I'm trying to emulate is:
[Serializable]
[XmlSchemaProvider("MySchema")]
public class SerializableEntity<T> : IXmlSerializable, ISerializable where T : class, new()
{
....
}
Error: Cannot Clear Table Table1 Because ForeignKeyConstraint FK_Table1Table2 Enforces Constraints And There Are Child Rows In Table2
Feb 15, 2012I have datagridview1 binded to data Table1 (with binding source) . This data table1 is in relation with his child data table2.When I insert new record to table1 I want to refresh datagridview1.
If I use table adapter fill method I get error.TableAdapter1.Fill(Me.DataSet1.Table1) ' error error: Cannot clear table Table1 because ForeignKeyConstraint FK_Table1Table2 enforces constraints and there are child rows in Table2.
DataTable Select Right Outer Join Query Triggers A "Failed To Enable Constraints" Error
Aug 9, 2011I am using/creating a DataTable so the "enforceConstrains" property is not avilable for DataTable.Error message: Failed to enable constraints. One or more rows contain values violating non-null, unique, or foreign-key constraints.
Windows Form Load Event:
Private Sub Expenses_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
expensesGV.DataSource = listExpenses()
expensesGV.Columns(0).Visible = False
End Sub
Developing Messaging Framework For Windows Application That Sends Messages To Java Application
Feb 9, 2009I am in the process of developing a messaging framework for a windows application that sends messages to a java application. To be precise when the win app wants to send a message it simply drops the message in a common database table which will be picked up by the java app. The windows application is deployed across 10 application servers (10 instances) over citrix for load balancing.Each instance of the application is capable of sending a message to the java application and each of these messages should have a unique id. From my end I need to make sure every message generated has to carry a unique id so that they can be identified when necessary. All the messages can be cleared every day or two.i am not quite sure about a best method of achieving this. Initially I wanted to create a static method that serves the next available id (incrementing the last id by 1). But this approach willn't guarantee unique number as the application starts only when at least one user is logged on. For e.g .On one server the app starts when a user logs in, he then sends a message and then the application stops when that user logs off. So when a next request for the app comes to that server a new instance will be started.
View 3 RepliesError Application Failed To Initialize Properly (0xc000007b) Click OK To Terminate The Application
Aug 13, 2009When I install .net Frame work 2.0 I had this Error when the setup writing system register values RegSvcs.exe-Application Error The application failed to initialize properly (0xc000007b) click OK to terminate the application and i have running an blank application (blank forum) and i running it in the VS 2005 IDE iget this error: windowsapplicatin1.exe-Application Error The application failed to initialize properly (0xc000007b) click OK to terminate the application and i have a program in setup package that i made from 1 week . i have install this program and when i want to run it i had this problem
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Message :'Application Failed To Initialize Property Ox700000000000000 ..... Click Ok To Terminate Application'
Apr 11, 2011When i click on my installed VB.net application icon on the desktop,i receive the message : 'Application failed ti initialize property ox700000000000000 ..... click ok to terminate application'.
View 2 RepliesRemote Desktop Application? Safe To Use Winsock In Creating A Client/server Application?
Jul 18, 2012Im planning to create a Remote Desktop Application and I'm having problem with viewing other computers monitor or screen.
Im not asking for the code on how to do it. and one more thing is it safe to use winsock in creating a client/server application?
VS 2008 Make One Application Send A Task To Another Application / Receive Result From That Secondary App?
Apr 26, 2010is it possible to make one application send a task to another application and recieve the result from that secondary app?i made a text editor program and i added a scan feature and i made another app that has ocr capabilities.The scanner ability is in my text editor program, the ocr program doesnt scan you have to input an image into it and it will give text result a few seconds later.the prob is alot of times the ocr code uses sooo much memory and crashes when its incorporated with my text editor, but individually each application works fine and doesnt take too much memory. Memory wont be even an issue if the ocr program is standalone so that when it is done decoding image the application can be made to exit. now here is the question, how do i make my text editor send the image to the ocr program and how do i make my ocr program send the text back to my text editor? is it possible? i mean the only way i know off is creating temp files in a certain folder and having a timer on each program that keeps waiting for temp files. That just seems like pretty lame coding to me i was wondering if there's a better way?
View 11 Replies.net - Store Application And User Settings Of An Application Running With Multiple Instances?
Jul 12, 2011Which is the best way to store application and user settings of an application running with multiple instances?My problem is that using the vb's "Application Settings" one instance would overwrite the other one.I want to identify each instance with a number passed via command line argument. I could use this number to identify the appropriate settings of the running instance, but I see in a local INI o XML file a better way to handle that.
View 1 Replies2005 : Crystal Reports Application Or Windows Application To Generate Pdfs?
Apr 13, 2011I currently have a simple crystal reports application which generates a crystal report and in the built in viewer provided by VS2005. There is a drop down where you can select options to change the criteria of the report. I wish to convert this app to a windows executable which will take all those select options and generates pdfs based on the crystal report. the executable will be triggered by windows task scheduler...or maybe command line app?
Obviously this will be somewhat of a re-write. What would be the best way to start this as? a crystal report application or a windows application.
Application Does Not Return From Call To System.Windows.Forms.Application.DoEvents?
Aug 2, 2011I have a windows forms application written in VB.NET which scrapes information from serveral web pages (who doesn't right)? Anyway, I am having problem with one particular site where partway through the page navigation my application hangs. When I press pause (or break) in the debugger, it stops on a call to System.Windows.Forms.Application.DoEvents.
Resuming execution shows that it really is stuck on this line (it does not reach the next line of code). It also hangs about the same point each time I run it (at least its consistent). Since System.Windows.Forms.Application.DoEvents yields to other threads on the same processor and then resumes execution of the current thread, I think the problem is that some other thread is not behaving well (not returning from some event handling code). I thought Windows 7 was pre-emptive, which makes me
doubt that theory but I really don't know.
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The program scrapes somewhere between 12 and 14 pages before it gets stuck on the call to DoEvents. Does anyone have a clue why this would happen? Why would any call to DoEvents hang?
Application.DoEvents() Function Halt And Crash Application In Windows Vista
Jul 18, 2011i made an application for serial communication. for this application i need to set delay time. during this delay time i m doing some other task. So for those task i need to take back control from delay function, for this purpose i am unsing Doevents() function.Its work fine On other OS (XP, Windows7 32/64-bit). But Application.DoEvents() function halt and crash in windows vista.
Private Sub TimeDelay(ByVal DT As Integer)
Dim StartTick As Integer
StartTick = Environment.TickCount()
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Convert Application To Platform Independent Mobile Application That Is Supported On All Devices?
May 13, 2011I have a vb.net windows application. I want to convert some part of it to an application that can be run on all mobile platforms like iphone,windows mobile, ipad etc. It should be platform independent
View 1 RepliesCreate A VB Application In VS2008 Without Requiring The Application Be Run On A Computer With A .NET Framework In Place?
Feb 26, 2010How can I create a VB application in VS2008 without requiring the application be run on a computer with a .NET framework in place?
View 4 RepliesCreate Uninstall Command For A Windows-based Application In The Application Folder?
May 27, 2009how to create a uninstall command for a Windows-based application in the Application Folder when creating a new setup project in visual studio 2008.
View 4 RepliesDeploying Winforms Application To Client Machines Application Failing On Start?
Jul 2, 2009Deploying Winforms Application to Client Machines Application Failing on start
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