Data Row Order Handling?
Mar 27, 2012
I am writing an application in vb 2010. The design of a program should be work in this way. Let's take an example.
ROW TYPE
1 APPLE
2 Orange
3 Grape.
Currently, i have a column named 'row' to control the display order for each item. i will sort the 'row' colum in order to display the record in the order when there were saved.I would like to find out is there any better way to achieve this? can i use the timestamp column in MS SQL?
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Aug 11, 2011
Private Sub Form1_Load(ByVal sender As Object, ByVal e As EventArgs) _
Handles Me.Load, Me.FormClosing
MessageBox.Show("form_load")[code]....
While closing the form I observed that the Form1_FormClosing method is fired first, and then Form1_Load second. Why is this order chosen? Why doesn't Form1_Load get fired/entered first, and then Form1_FormClosing second?How does .NET choose which method to fire first, of the two that handle the same event?
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Apr 17, 2010
I have a databound Datagridview. The DGV is bound to a datatable of a strongly typed DataSet created using the wizard. Is there any way to re order the columns before displaying them eg: the Columns are displayed in the DGV in this other Col4, Col6, Col3, Col1,Col5, Col2
But I want to it to show as Col1, Col2, col3, Col4, Col5, Col6?
I realise that the display order followed the Column order in the database table and by extension, the datatable. I have re-arranged the columns in the Database but the Datatable still retains the old order.
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Nov 10, 2009
I'm currently working on a project where I am transmitting data from a comm device via the serial port and resorting the raw data (in binary) to its respective ascii values. The problem I'm facing is determining the most efficient method to accomplish my goal. Essentially, I have 68 bytes coming in, the first and second bytes represent the page and packet number and the data itself ranges from 3 to 64, the remaining for my checksum.
What I am needing to do is, grab 50 consecutive bytes per variable in my array, and that is where I'm confused. I have easily pulled my 3-64 bytes and stored that data to a string. I just don't know the most efficient method to accomplish my goal. Should I write directly to file all my data, as there are like 8 pages, of 128 packet data. [Code] I can capture the the first 50 by using a for-loop easily, but what would be the preferred method to track what data chunk I've taken? The more I think about it, I think I may just want to write to file, all my data, and then just take them back to back in 50 byte chunks. Is that the most efficient method?
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Aug 13, 2009
Iam having major difficulties handling a binary stream which I am trying to read and process in vb.net. The stream is coming in from an FTDI chip and should contain 64 8-bit values.An example of the stream is here
����������������������������������������� ����������ٶ��������
I need to get this into something that I can read (decimal or hex or 1s and 0s) in vb and I just don't know what to do - I tried using Asc() but it wasn't working and I know now that it can't work with characters higher than 127.
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Apr 29, 2010
I'm writing a simple application - address book. User enters new addresses and they are added as an entry to a list visible on the main form (frmStart). I use one form to add and edit (AddContForm). Add button on the frmStart works fine, however I experience some problems with the edit button as when I press it and enter new data they are added as new entry however the previous entry is still there. Logic is handled by Contact.vb class.
Contact.vb
Public Class Contact
Public Contact As String
Public Title As String
[code]....
Update:I really don't care much for whether the data on the AddForm is the old data or the new data. I think the problem now is that when I click edit previous entry on the list is not deleted (what I believe I have indicated in my question) - I tried to delete it (by using the if condition and checking what button was pressed) however it seems it is not working properly for some reason.
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Apr 23, 2011
I am currently creating a Windows App for a handheld device (WM 6.0, CF 2.0, sqlce 3.5) that pulls data from the server only when connected to a dock (all the significant data is maintained/altered on the handheld til it comes back and is docked for a sync with server).The data is similiar something UPS would do in that it manages pickups and dropoffs of items from a location to a location and records the time these "transactions" occurInitially, the handheld has a couple source tables (pickups and dropoffs) and some validation tables. During a given pickup or dropoff, I am trying to figure out the best way to move the data along this multistep process
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Nov 12, 2010
i am coding in vb2008 express.Can u suggest me any tutorial or sample code for "Handling Data between multiple forms".
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Jun 30, 2009
I am working on an application with plugins. I have created the plugin host and the plugin, now I need to figure out how to pass data back to the main application from the plugin. IE: I have MainApp that has plugins in a subfolder. It loads the plugins and shows a menu item the launches the plugin. When the plugin launches it opens a windows form inside the plugin. The form does some calculations and then returns data in a string array. How do I pass that string array back to the main application?
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Sep 15, 2010
I have a VB.Net 2008/Access 2007 app that I can�t get to display data in an organized way on a listview. The listview displays the data in the order that the data was entered in the products table. In the SQL statement that loads the listview I put ORDER BY SupplierTbl.CompanyName but it doesn't do it. The listview shows the data in the order that the records were entered in the database. So then I was going to settle for if I can get the listview sorted by clicking on the column header.If I can get that to work then that would be acceptable. So I then implemented the sort routine. The sort works and it doesn't.If you click on a column header then all the rows show the information nicely. The database has an OLE object column for storing images. Customer wants images stored in the database not file paths. When you click the listview the image displays in a picturebox.
The proper images display when the listview is clicked when I use the SQL statement below without the ORDER BY. But when I click on a column header and reorder the display it's no good. If you click on a row in the listview the wrong image is being displayed. It displays them in the order as they were in before the sort. All the other columns look good and are behaving except for the Image column. So that then makes me wonder if my original problem with the ORDER BY is directly related with the OLE object column. Is there something about this data type that I need to know to manipulate it in SQL? My reaction is that maybe since this column is resource heavy it goes by different rules. Can someone please tell me what I need to do to make the end result have some order? This is the SQL statement without the ORDER BY:
command.CommandText = "SELECT ProductTbl.ProductID, ProductTbl.PartNumber, " & _
" ProductTbl.AltPartNumber, ProductTbl.Description, ProductTbl.SupplierID, " & _
" SupplierTbl.SupplierID, SupplierTbl.CompanyName, ProductTbl.Category, " & _
[code]....
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Dec 1, 2009
So, I have a little issue.. I can't currently explain it using the software I'm developing because it's "internal"... So I'm going to describe it as an email serverAnd the email server has a fair number of email accounts, and I want to save the accounts emailFor development, I've been saving it all in a list of a structure (this sounds worse than it is, the data actually is no more than 120 bytes per "email")
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Aug 6, 2009
How do you handle the screnario wherein multiple data entry forms are open and modifying one could potentially affect the record being modified in other forms?
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May 28, 2009
What are good things to check for, with respect to error-handling, when you are dealing with the data-access-layer? For example, let's assume I have this function..
Public Function UserExists(ByVal userName As String) As DataTable
Dim dt As Object = Nothing
Dim arSqlParameters(0) As SqlParameter
[code]....
How would you go about ensuring that your code elegantly handles anything unexpected in a situation like this?
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Jun 30, 2010
how can i reverse the order of a data table?
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Nov 12, 2011
I've been working on this project for about a year now. It's a basic clientserver chat program. After a long time of improvement, I decided to test out the strength of my server.
On the client, I fired off 200 chat messages ("FLOOD# 1"... "FLOOD# 200") to the server as fast as possible. The result: Server immediately crashes. After some slight tampering, I was able to get the server to process 135 of the 200 messages before giving up. It no longer crashes, but something different happens. The data from the client is received in order, but when I pass that message to a function (myForm.OnLineReceived), The data is completely out of order. If I add a slight delay between the calling of the OnLineRecieved function, The messages are in perfect order.
Each message from the client is first encrypted, then encoded in base64. An "-" is appended to the end so that the server can easily find the end of each data "packet".
Server Code:
Imports System.Net.Sockets
Imports System.Text
' The UserConnection class encapsulates the functionality of a TcpClient connection
' with streaming for a single user.
[Code].....
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Mar 14, 2010
I would like to build a base class for my SQL Data Access Layer. I have most of it based out, but have a question about how to handle errors within the base class. I have a method for ExecuteNonQuery, ExecuteReader, ect...
[Code]...
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May 7, 2009
I need to consume data from a webservice. I am receiving xml data and using this to create objects through property setters.
In one particular case, an attribute of the object (called "is_active" and indicates whether the object is active or inactive in the application) is represented sometimes by
<field type="BooleanField" name="is_active">1</field>
and at other times by <field type="BooleanField" name="is_active">True</field>
The client code requires me to represent this using integers 1 and 0. The returned string "True" or "False" results in System.FormatException, as expected.
What is the most graceful way to deal with this situation?
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Oct 6, 2011
I have a delete button in a datagridview. The button works fine however when there is nothing to delete it throws an index out of range exception. Now I know for a fact people are going to click that button even though there is nothing the I am presuming the best course of action is going to be a try/catch but I am not sure how to do it. My code is as follows,
Private Sub DataGridView1_CellContentClick(ByVal sender As System.Object, ByVal e As System.Windows.Forms.DataGridViewCellEventArgs) Handles DataGridView1.CellContentClick
If e.ColumnIndex <> 7 Then
[code].....
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Nov 1, 2009
I have a combo box bound to a datasource. I need to change one combo box (of many) to order the items in descending order.I'm guessing I could order the collection in the dataset, but that will mean all my combo boxes will be reordered?
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Jun 20, 2012
VB 2010 Express + MS Access 2003
today I successfully configured an interface to work with a test database I created in MS Access 2003. The database consists of only 8 records with 10 fields.
I used the basic built-ins with VB 2010 to build the interface in a simple form which shows only 6 of the 10 fields. It all seems to work well, that is the connection string built correctly, and I can run the program and view the individual records. My trouble is that when it goes to the 1st record it's actually the 3rd record in the database. And when I go to the last record it's actually the 2nd record in the database and the next to the last record is actually the first record in the database.
why the program seems to start at the 3 record and shifts the first two records to the end. All the records show up, it's just that they are somewhat out of order.
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Jun 25, 2010
I am using GUID for uniqueness (Guid.NewGuid.ToString), but while getting data from database some time GUID order is mixedup.
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Jun 10, 2011
i'm having trouble opening a text file to process and order the data in it. When i try to read the first line of characters an error message occurs saying: 'Variable words1 is used before it has been assigned a value.' I dont understand what i am doing wrong when opening the file. Also, I am sorry if this is a rather basic question.
[Code]...
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Jun 22, 2010
I have an Excel based algo-trading app that needs to take in lots of real-time data, and make trading decisions based on the calculations driven by the data. It is not one of those "read-only" stock ticker kinda spreadsheets.I created a COM object with VB.NET that runs in its own thread space which collects data from a socket, and when the data is read it raises an Event with data attached. In Excel VBA, the event handler parses the data, puts them to the right places on the spreadsheet to feed calculations (so far it sounds like a stock ticker app), and then, based on the results of the various calculations it does something.The problem is that when the user starts to click around the spreadsheet while there is large amount of data coming, the event handler's cell updating breaks apart. If the app is left alone without user action, it stands well. My frustration comes from not understanding what happens to the main thread when a user clicks around. Either the event handler blocks the user action, or the user action blocks the event handler (under which case I will put in some queuing facility). But I just don't see how user action can break the code (like causing VBA to stop executing)
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Jul 13, 2010
I use Visual Studio 2010 and SQL Server 2008 R2. I have created an Entity Model in a class library which I have referenced in a VB Winforms project. I created a data source in the project based on the entity model in the dll. However, all columns in the data source are listed in alphabetical order instead of the native order from the SQL Server database. I cannot locate the cause of this as much as I try.
This might not seem a huge problem, but it is costing me valuable time in rearranging controls dragged to forms and reindexing their tabstop indexes.
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Mar 5, 2012
I am getting data from an SQL Server database and displaying the data on a Windows form.How do I navigate through the data in a Sequential Order or Sort Order using the the REP_ID number? Example: When I use the navigation to move from one data to the other, can I go from; example: 100001 to 100002 and so on?
Finally is there any hint as to why I am getting the time with the dates? I know it is converted to text but not sure how to remove the time and just get the dates.Here is the entire project code:
Imports System.Data
Imports System.Data.SqlClient
Public Class frmBindingData[code]......
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Oct 8, 2011
This might not be so 'VB' as it is 'SQL using VB' I have an application with a built in MS Access DB. I have a table that has a column full of integers, I shoot the DB a SQL "order by 'column name' " string and it returns the table ordered by my column of integers.BUT it returns them like this, and I want them like this
0 6
1 5
2 4
[code]....
How do I get the OrderBY to do a descending list starting with the highest number?
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Aug 18, 2011
I'm working on the exercise page 73 (VB 2010 in 24 hours). It's basically a form with 2 text boxes, 2 text labels and a command button. It's really simple and uses this loop to cycle through the items, and tell me the name of them in a Messagebox
[Code]...
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Nov 1, 2011
I am attempting to create a basic program and I need to know how to incorporate INI files for profiles in order to quickly pull up data from one person to the next.
Public Class IniFile
' API functions
Private Declare Ansi Function GetPrivateProfileString _
Lib "kernel32.dll" Alias "GetPrivateProfileStringA" _
[code]....
And placed it into a module, which I then wen't to my main program and attempted to place this:
Dim ini As New IniFile(Profiles.ini)
Dim value As String = ini.GetString("Names", "1", "Default Value")
To attempt to retrieve the data, but I get no error or information from it. The ini file is inside the folder of the project and I set the SectionName and KeyValue to the corresponding names. I think I am having trouble with syntax? Not 100% sure. This is the code that I got from the same source as the module for using the module.
Dim ini As New IniFile(FileName)
Dim value As String = ini.GetString("SectionName", "KeyName", "Default Value")
And I adjusted to what I believed would be the proper format.
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Oct 21, 2010
I am using Streamreader to read a text file containing data such as the following:
IN;SC;PU;PU;SP1;LT;VS10
IN;SC;PU;PU;SP1;LT;VS10
PW5;PU4179,27448;PD4179,29951;PD3244,29951;PD3244,30286;PD5494,30286;PD5494,29951;PD4555,29951;PD4555,27448;PD4179,27448;
The final goal is to use the numbers next to the PU and PD characters to perform specific calculations.
Essentially, I think the code needs to do the following:
1. Read each block of characters ending in a ";"
2. If the block commences with anything other than PU or PD, discard it
3. Extract the numbers in such a way that calculations can be performed. The following is an example:
x y
PU4179,27448;
PD4179,29951;
[Code]....
Essentially, there will be hundreds of these rows and I will need to sum up the deltas so that a specific formula can be applied.
I have tried doing this a number of ways but each seem very inefficient (using text boxes to store/swap data and creating additinal text files are 2 methods I have tried) and so I'm looking for some direction.
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Dec 3, 2009
I'm working with Crystal Reports in VB.NET in Visual Studio 2005.I have a List(Of Stuff) that I've sorted according to one of the object's members.I've verified in the debugger that the list is sorted correctly.When I define my list as the data source, as in
rptDetails.Subreports.Item("rptSubReport").SetDataSource(theListOfStuff)
and view the report, the list is reversed.So, looking for a workaround, I said, "OK, I'll sort the list backwards before binding it."The list still appeared backwards in the report.So something's happening, and I think it's within the report definition, because I don't know where else the sort order could be changed
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