I run VS 2010 Premiuim version. I do a lot of data projects and wondered what option i have to setup concurrency if the returned object is a dataset and how do i do it? Does VS 2010 have any built in options for me to take advantage of?Or if anyone else has any other ways of doing this please advise or point me to any articles.
View 4 RepliesWhen my project starts, it first checks for the existence of certain rows in the database. During testing, I often delete these rows, as they get kind of messed up over time due to all the odd tests I am running. For that reason, if when the project starts, if the records are not there, the program first creates them.The records are pretty static over the lifetime of the project, so they are held in a dataset for ready access from various parts of the program. Therefore, if the records are not in the database, the records are added to the dataset, and the dataset is updated back to the database. This works without any issues.However, one of the easiest actions to take will cause one of these records to change two fields, and a new record will be added. Those are all the changes that are caused by this action. Those changes are then updated to the database...or so I hoped, but when I try that I get an exception stating:[code]I have looked at the datatable that is being updated, and there are, as I expect, two records being changed. One of the records is the new one that is being added, while the second record is the record that was changed. I have noted that the change is, in fact, different from what is in the database, so this really IS an update.
However, I also noted that if I then stop the program and start it again, all is well. This indicated to me that it was actually the routine that created the records that was causing the trouble. Therefore, to test this out, I tried a totally horrible solution. I altered the method that writes to the new records to the database so that after it wrote each record, it would clear the whole dataset and fill it all again. That's obviously a terrible thing to do, but it works. If I write each record, throw out the dataset and re-create it, then I don't get any exceptions when I later try to modify it.This makes no sense to me. What am I doing in that first method that could be putting the Dataset into a state where it fails on any further modifications? I should add that the code that actually pushes the changes to the dataset down to the DB is the same for both methods. In fact, the database is updated in an UpdateDB method that is called from that first method (which creates the initial records if they are missing), as well as being called by the other methods that alter the dataset. I have also confirmed that ANY alterations I want, whether they add, remove, or just alter records, works fine. It is only that one method that creates the initial records that is causing me trouble. Moreover, it is not the actual update of the DB that is doing it, since that same method works fine ever after. Further testing has showed that the issue is row by row. As each initial row is added, it can't be modified by any other code until the dataset has been re-read from the DB. url...
How do you restore a dataset to the previous state before updating the database with a data adapter? I have a concurrency update problem that I believe to be caused by this. The update fails during the update and a rollback command is issued using a SQLTransaction object. However, now the rowstates of the rows that did not have errors have been changed to unchanged. So this record is no longer availible to be inserted into the database. When I updated the value that could not be null and then test the second update which runs just as the first does then I get a concurrency error. The update code is below:
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I have a model that returns a dataset to a view and builds a list. The crazy thing is that I have tested this code with IE, Safari on Mac and Windows, Chrome and Opera and all return data. However, on the iPad or iPhone, zero rows are returned from the dataset object. It seems that the model is in fact passing the dataset to the view. I am using jquerymobile to render the view for the iOS devices and have taken that out of the mix to test and it still doesn't work.
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I am using Enterprise block and not able to figure this out.
I am using oracle procedure for inserting records into the database from my asp.net application in VB.net
Though it is inserting records as it should When I try to access the dataset returned I am not able to see the just inserted record details.
In my Oracle procedure I have Output Cursor which should return several column values from the just inserted record.
I am returning to VB and coding after several years of trying to be out of coding :)
I would like in grabbing data retrieved from a SQL database call into an array of sorts so that I can quickly close the database connection. I am having some trouble remembering how to do this. Most of the posts I've found say to use the dataSet() functionality, but I do not have a table name for the structure to mimic. I am selecting from several tables on a remote server.
I'm trying to re-write an old VB 6 OCX into a VB.net DLL and I'm having problems accessing the object returned from a COM object. Here is a snippet of the old VB 6 code: Dim objResult as Object
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How can I get round this error: Option Strict On disallows implicit conversions from
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I have a dataset which creates a table adapter to the table I need. I call a query on that table adapter which returns the number of fields returned. In this case it's one field and will always be one field.. I am filling a variable with that query.. however instead of the fields returned I need the actual data.
This is how my current code sits...
vb.net
Dim aUserName As String
'TODO: This line of code loads data into the 'DataSet1.IT_Staff' table. You can move, or remove it, as needed.
aUserName = Me.IT_StaffTableAdapter.FillByUsername(Me.DataSet1.IT_Staff, SystemInformation.UserName)
Do I have to load this into a variable declared as a datatable then somehow call the column and row 0's value? If so how?
Is it possible to create an uninstall option in the setup package?
View 1 RepliesI know how to create shortcuts on desktop and program files but i want to make an option with checkboxes...so that you can select if you want those two shortcuts or if you don't them.I've tried this with checkboxes (in User Interface), i've set checkboxes properties and changed "User's desktop" and "User's Start Menu" conditions (in File System). "CHECKBOXA1" for desktop shortcut, "CHECKBOXA2" for start menu shortcut...but it doesn't work... both icons are visible every time.
View 2 RepliesIs it possible to create an uninstall option in the setup package?
View 1 RepliesIn .Net Setup Wizard , While Installing Application Wizard shows ' Folder where to Install' but I want to show only Drive Letter like C, D etc Not to give option of folder
View 1 RepliesThis should be a fairly common question, but I haven't found a straightforward answer anywhere.
If I instantiate an object within a function in VB.NET and return it, does it return it be reference or by value. IE - should I be worried about performance if I write something like this:
Public Function ret_obj_func() As big_object
Dim ret_obj As New big_obj(<lots of stuff>)
Return ret_obj
End Function
If I call this function from somewhere else, will it instantiate the object in the ret_obj and then create a deep copy to pass back a copy to the caller, Or will it just pass back a reference?
I am currently writing unit tests for an application near completion (before management looks at it and turns it inside out). I am testing the business layer and a method is set to return a datatable of all "GroupID"s, which are simply an integer to represent the group that a user belongs to.
I'm assuming the best way to assert on this unit test would be to assert that the correct groupIDs are being returned from a controlled test database. However, I'm not sure how to assert on a datatable. Is the only (and best) possible way to accomplish this to simply loop through the datatable until it's empty and add each value to an array of integers? How would one go about asserting on this test?
If I instantiate an object within a function in VB.NET and return it, does it return it be reference or by value. IE - should I be worried about performance if I write something like this:
Public Function ret_obj_func() As big_object
Dim ret_obj As New big_obj(<lots of stuff>)
Return ret_obj
End Function
If I call this function from somewhere else, will it instantiate the object in the ret_obj and then create a deep copy to pass back a copy to the caller, Or will it just pass back a reference?
I am tightening up my coding with the Option Strict set to ON. It has now produced alot of errors. An example of this is:
If AllocatedDGV.Rows(i).Cells("RoomNumber").Value = RoomsAvailableDGV.Rows(j).Cells("RoomName").Value Then
It gives me the following error: Option Strict On disallows operands of type Object for operator '='. Use the 'Is' operator to test for object identity.
I need to write an interface to get data to/from our data files.
We have a low level class that holds field values for each record read from the files.
This just holds two values, the value read from the file (DBValue) and the updated value that may need to be written back to the file (CurrentValue).
These values may be any of the standard value types (integer, date etc) or a string.
Either value (DBValue or CurrentValue) may be null if not defined.
I have written the class to manage this data which works fine while option strict is NOT on.
But we have an office policy of having option strict on all the time.
When I put option strict on, my object value comparisons fail with the error: "Option Strict On disallows operands of type Object for operator '='. Use the 'Is' operator to test for object identity."
Question, how should I change the following code to handle option strict on ...
This is all running on Visual Studio 2010
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I am developing a software that will be installed on 3 servers using sql server 2005 + replication.
In my development I want to use sql server with dataset.
When I finish the project at my development machine, I want the ability to install it at these 3 servers.
What is the best way to configure the connection?
Can I change the connection string created by the wizard during run time?
Trying to replace Cells(RowIndex,ColumnIndex).Value() calls by row-wise references for performance, I permanently fail at referencing the result. Starting with Excel Interop - Efficiency and performance, which contains the tip to use get_range, i.e.
//get values
object[,] objectArray = shtName.get_Range("A1:Z100").Value2;
iFace = Convert.ToInt32(objectArray[1,1]);
//set values
object[,] objectArray = new object[3,1] {{"A"}{"B"}{"C"}};
rngName.Value2 = objectArray;
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However, referencing Values with two dimension indices always returns an "index was outside the bounds of the array" exception. Inspecting the array with the debugger shows a nice 2-dimensional array which should has 17 elements on the second dimension, so Value (0,0) should indeed be a valid reference -- but it isn't:
The debugger lets me inspect Value, I can also drill down to Value(0,0) and see the correct value, but re-evaluating just that element, i.e. inspecting "Value (0,0)" returns above message.
http://127.0.0.1:47873/help/1-6644/ms.help?method=page&id=C318B79A-FA4D-4DE3-B62D-C1162BEB267E&product=VS&productVersion=100&topicVersion=100&locale=EN-US&topicLocale=EN-US
and i get the following error
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Given this definition of an incoming byte array I get the following error.
View 7 RepliesI have an error in my VB.net program - I have tried various casts etc but it just will not resolve the issue - so reluctantly I post it here to see if anyone else has a similar problem.
Error 1 Option Strict On disallows implicit conversions from 'Object' to 'String'.
Private DS As New DataSet ' Languages
Function TransTxt(ByVal Frm As String, ByVal Item As String) As String
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I get "Option Strict On disallows implicit conversions from 'Object' to 'ExpTreeLib.CShItem'.", which is a listview that I have on my form, which references expTreeLib.dll
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Im doing my first project with WinForms, and Im trying to get the DataBinding working. Theres no database in my project, but I'd like to bind some of the TextBoxes to objects' properties. In the other section of this forum (here) I found this line of C# code which does it: textBox2.DataBindings.Add(new Binding("Text", this.myPerson, "LastName"));
my question is can data binding to object properties be set up during design time (without writing code)? If so, how? P.S. I know how I would set up this binding if in WPF, but I'm forced to use WinForms.
Ive have a listview on my form and need to populate it with data from my Table called "tblCustomers". However I need to only retrieve records based on field that is populated with data called "Joe". In order for the SQL syntax to retrieve the name "Joe" then the SQL syntax needs to reference the Label on the form called "lblName" which will have the name "Joe" as the caption.
How can my dataset have SQL data that references my label object on my form?
I was given a task of rewriting some Crystal Reports. I found the original reports circa 1999, opened them up in VS 2008 made the changes and saved them.Now, they reference a database that is no longer around. So, I deleted this data source and added a .NET OBJECT datasource. I changed everything around so that the fields now look at this new datasource.
My intent was to create the report and during run time, pass it a datatable. This table is created by running a sproc created.When I run it, I get the first page of the report. But when I try to change pages or print, I get an error: Logon failed. Details: crdb_adoplus : Object reference not set to an instance of an object. Error in File C:...MR01 {8E5164A9-4B01-4019-81E6-87AED65A02DF}.rpt: Unable to connect: incorrect log on parameters
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I have a collection (IList(Of Sample)) of the following class:
Public Class Sample
Public sampleNum As String
Public volume As Integer[code].....
This collection is filled from a regex that gets passed over a file.What I want to do is use Linq to generate a collection of these for each unique samplenum using the following conditions.For each samplenum: Have the highest volume where the final is greater then one
If the sample has multiple records for this volume then pick the one with the the highest final
If the previous step leaves us with no records pick the record with the highest final ignoring volume
I am extremely new to Linq and just can't get my head around this. For now I have solved this using for each's and temporary lists but I am interested in how this would be handled using pure Linq.Sample Data:
samplenum | volume | initial | final
1 | 50 | 8.47 | 6.87
1 | 300 | 8.93 | 3.15[code]......
I really like the coding speed that vb.net provides, but I don't like the possibility to forget to declare variable types, return types of functions, etc. and that is why in each class I use[code]..
Is there a way to define those two options on the project/solution level?
the combo box style 1 has both the drop down option but also a manual entry option. I need to know how to code it so that when you manually enter data, it takes that data and places it in a text message "The shipping charges for "data" is $15" displaying in a text box. Shouldn't be hard but have developed a mind block.
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