Limit Result Being Put Into DataSet And Get Next Result From Database
Apr 16, 2010
I just read about DataSet in VB.NET, it uses disconnected concept. My question is: if my apps has "List All" button that query data from 1 table in the database, and that table has "very very very" many rows, so my DataSet will be filled with those data and eat up memory. Can I limit the data that being put to the DataSet from that query? But I want to be able to retrieve the next data from the same query if the user want to see it?
For example:
I have 1000 rows in my database, and i query all of them. But I just want 200 rows being inserted to my DataSet, but if the user want to see rows number 201 and so on, I want to be able to retrieve the next 200 rows, and so on. So it just like cutting those data into a group of 200 rows. Can I do this with the concept of "disconnected" of the DataSet?
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Dec 10, 2010
I am currently having a headache on how to solve this problem that i am facing. here is the situation: I have a combobox and a list box on the main form. The combobox will get the data from the ms access database. In the database, i have the details of a person's IC, Name and DOB say for eg on one entry I have D215311523C,SHAWN,13/04/1987 So now, my combobox on form load will show the list of dates in the database to allow the user to search base on the date itself by clicking on the selected date. So when the user clicks on the particular date say 13/04/1987, people in the database whose birthday is 13/04/1987 will be shown on the listbox.Meaning to say if i have 3 entries whose dates are the same 13/04/1987, 3 entries will appear. If there is only two entry, then two results will be shown. But now, when i do a single click on the date, one result will be shown. That is correct. But the problem is when i click on the same date again, three of the same results will be shown on the list box. that is it will display : 13/04/1987 13/04/1987 13/04/1987 which is not the case. Then it will show more duplicates of the same results if i click more times on the same date which should not be the case.
Dim n As Integer
Dim numbers() As Integer
Dim StartFrom As Integer
Dim EndAt As Integer
[code].....
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Sep 25, 2010
I am using a datagrid in my where i am having four columns. In first column the parameter values are entered and in the second column measured value is entered and in third column the nominal value is entered.Inthe fourth column the result is displayed by subtracting the measured value and nominal values. I am doing this calculation in Datagrid cell validated event. What i want is,there will be many rows in the grid,when typing the value in the third column the corresponding result will be displayedin the rowof theresult column,save button will be displayed while the form loads,when the calculate part is completed that is there should not any cell of the resut column empty then i should enable the save butto.
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Oct 14, 2009
I am encountering the following issue So i have a device that sends stuff at the serial port, i then parse it and put it into an array of bytes like that:
Dim HCI_Command_Rcvd_Byte() As Byte All good till here What i wanna do is make an array and put this result every time the serial port gives me a new result, for example:
[Code]...
Basically what i wanna do is let the port parse the messages, fill in the array with the result at an empty spot in this array and then i will have a separate thread that will look in into this array in each non empty space and after it looks into the non empty space it will use or discard the info and also mark this space as empty (after it checked)
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Dec 20, 2011
I'm trying to validate the contents of a datagrid cell against the values in a Dataset:
VB
Private Sub dgOperator_CellValidating(ByVal sender As Object, ByVal e As System.Windows.Forms.DataGridViewCellValidatingEventArgs) Handles dgOperator.CellValidating
[Code]....
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Sep 14, 2009
How do you compare the contents of the textbox with result of the dataset?
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Jun 6, 2012
I have a small section of a windows form that allows users to select when a customer should be called (i.e. day of the week, time and inbound or outbound)When the form is loaded I will extract the information using a dataset and bind to form controls. I want to use a combo box for call stautus - inbound or outbound - however wish to give the user the choice at runtime.My thoughts are I would need to set a static list (so the user could choose) and set the default or displayed value to the info the dataset has extracted.This code to select the index doesnt work when I am comparing the dataset result to the "Outbound" string even though I am using the ToString method.
Private Sub TestTelesalesForm_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
Me.Telesales_DEV004016TableAdapter1.Fill(TelesalesDataset1.Telesales_DEV004016)
Me.comboCallStatus.Items.Add("Outbound")
[code]....
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Apr 3, 2009
Lets say i have a class Employee which cotains two propeties (Name, Year) I have another which basically contains list of Employee object i.e EmployeeList.[code]...
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Jun 21, 2011
I have set up a method in vb.net and in xcode for encrypting a string using as far as i can tell the same parameters for an AES encryption.I've looked all over the place but cannot find information on whether they use the same encryption algorithm and settings.
this is the vb.net code:
Dim encryptAES As New AesCryptoServiceProvider()
Dim encoding As New UTF8Encoding()
Dim encryptor As ICryptoTransform
encryptAES.Key = encoding.GetBytes("12345678901234567890123456789032")
encryptAES.IV = encoding.GetBytes("1234567890123416")
encryptAES.Mode = CipherMode.CBC
[Code]...
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Nov 24, 2009
In my .NET application I have to manage bookings for rooms. I enter the room booking via an SQL query to a MS Access database using an INSERT INTO statement.
Before I insert the booking, I need to check if a booking already exists for that time period, and if it does stop the user from being able to book at that time.
I have written code to retrieve a database result on the day and time of the booking they want to book, and the fact that Access would return data would mean that the user is trying to book over someone else.
how I can check if I have a resuklt returned. My code:
cn = New OleDbConnection("Provider=Microsoft.Jet.OLEDB.4.0; Data Source=D:Databasedatabase.mdb;")
cn.Open()
[Code].....
But this doesn't work, it displays the messagebox regardless of if there is a row returned or not. How can I check if a row was returned?
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Oct 3, 2011
I created a small databse program, when I created the search field I wanted to display the results in "listbox" which I found some code that work perfectly
For each row in ds.tables("Tablename").rows
me.listbox1.items.add(row(1).tostring())
Next
but I also need to display "row 2" ACCORDING to the selected item from listbox in a textbox.
since the listbox is displaying the result of a search, it's been hard to find, how to do this?
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Jun 19, 2009
I am trying to read a single result from an SQL table. I tested my query in MySQL Query Browser and it returns a result of USER_ID=4. My query:
SELECT USER_ID FROM aaalogin where NAME = 'administrator'
I believe my error is due to some "double quoting". I have a "txtUsername" textbox on my login form. I want to inject the typed entry from this textbox into my SQL QUERY. Notice the end of this line, I have tried tons of combinations, nothing works.
myCommand.CommandText = "SELECT USER_ID FROM aaalogin where NAME = " & " ' txtUsername.Text ' "
The result is ALWAYS "0" though, which is useless to me.
Full code below:
Imports MySql.Data.MySqlClient
Imports System.Data
Public Class frmLogin
Private Sub cmdCancel_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles cmdCancel.Click
Application.Exit()
[Code] .....
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Jun 7, 2012
I have a windows form application that uses datasets and mySQL. I am wondering how I would get started in making one of the buttons blink dependant upon database status.In short each record has a column where the user marks a received checkbox. I would like for a button to blink if there are any request that are not marked as received.
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Mar 24, 2009
StudentId Marks obtain class
1001 76 NINE
1002 75 NINE
1003 55 NINE
1004 62 NINE
1005 38 EIGHT
1006 56 EIGHT
1007 31 EIGHT
1008 57 NINE
1009 48 EIGHT
1010 55 NINE
1011 49 NINE
1012 49 EIGHT
1013 27 NINE
1014 31 NINE
1015 48 NINE
1016 58 NINE
1017 31 NINE
1018 36 NINE
This is my database now I want to calculate rank from above this. I call this through procedure. If I select id 1001 then it will display the rank from the above data base. If I select 1007 then it must display rank to class eight.
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Feb 10, 2010
How do i code so my program will give me a message box if there are no result of my database search?
there is the code for the search. [Code]
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Apr 6, 2011
How do i check if the command insert new data in my ms access database this is my code so far.[code]...
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Dec 8, 2009
The main problem is I couldn't display the result when I retrieve data from database.
1. On Picture 1 above, for the Dg_Details, I set the Columns in two type, textbox and checkbox. But, for the datagridview1, I didn't set anything.So, when I bind data from database to Dg_Details and datagridview1, the datagridview1 display the data from database, but the Dg_Details doesn't display the data. Below is the code I written in my form :
Try
objCommand = Me.MyConnection_F.open.CreateCommand
objCommand.CommandText = "select Reg_Num, Reg, Golf, Course_1, Course_2, Course_3, Course_4, Course_5 from Invoice_Reg where Receipt_No = '00001'"[code].....
I think that's happen because the Dg_Details already set and it blocked the result data from database.
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Nov 17, 2009
This is what I am trying to achieve.Lets say you got a database with say 4 colums.. eg.. Name , Acc Num , Amount , TotalThen I need to create a GIF of say 4 slides with the same background , BUT with the merged information as above from the database.
Application as follows :-
I wish to send out BULK MMS's with Client Statements.. Each one being personalised with the info as above. The MMS will contain the personalised GIF above.
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Oct 8, 2009
hi there,first of i know nothing at all and my goal is to make a app for xp to check a database and check/patch a iso and then to burn the result to dvd-dl, basically like a app called abgx360 checks the database then like xbox backup creator burns the game, i'd like to make a app to do both, i'm going to college next year in september to learn programing c+ andf a few other things, but thats a longtime away.
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Apr 8, 2012
I have a table which contains a list of products for a company. They input data about how much stock they have and also the level at which they want to be reminded that they need to order new stock.
[Code]...
I want to list all the true results in a form which the user is then able to navigate through. What would be the best way to go about doing this?
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Sep 14, 2011
I need to run TWO Threads in a web application, .NET. 3.5 Both methods MakeRedCars and MakeBlueCars need to run at the same time as both take 5 seconds. I have tried many example codes with very bad results. I dont need anymore than 2 threads. The main issue I am having is knowing how to wait till they are finished and also how to store the results from each.Each of the Methods do different things, one is a web request, one is a sql call.
Both methods return a list of(cars) for example do:
carList.addrange(MakeRedCars())
carList.addrange(MakeBlueCars())
for each car in carlist<br>
response.write(car.colour + "<r>")
next
I have implemented the answered below and with empty objects all works well, as soon as you hook in a database call that returns the data/objects studio does a JIT and crashes.
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Dec 2, 2009
I need to check if my SQL statement returned any results from the Access db I'm using to store my data.
I have this code atm:
cn = New OleDbConnection("Provider=Microsoft.Jet.OLEDB.4.0; Data Source=D:Computing Projectdatabase.mdb;")
cn.Open()
[Code]....
I would like to be able to check (maybe via a boolean value or something) that this result returned a query. I'm using VB.net.
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Feb 29, 2012
As of right now I am getting no compile errors with my code, everything runs they way it is supposed to go except for one minor detail. I have a private function named MonthlyPayment() that does a calculation for a loan. The calculation runs as expected and I get the correct results by typing in Console.WriteLine(MonthlyPayment()) but it is not in currency format. To fix this I set FinPayment equal to MonthlyPayment [FinPayment = MonthlyPayment()] and typed in Console.WriteLine(FinPayment.ToString("C")), But this just gives me NaN as a result.
Here is my full code:
' The following code was created for McBride Financial Services to use to amoritize loans.
' This console code will calculate and display the monthly payment amount to fully amortize a loan.
' This console will prompt the user to input values for the loan amount, the term length, and the rate.
Module Module1
'Declares strings used for user input values
[Code] .....
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Jun 5, 2010
I declared a variable which is the sum of two other variables. I simply want to display that result on the screen. I think a msgbox is what I need to use but I'm not sure.
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Feb 11, 2010
I have a Search function on my database.It countīs how may search result you get but now i want to load one column from each search result ( for each row in a DataTable ) into a "ToolStripDropDownButton.dropdownitems".[code]
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Sep 30, 2009
I've got two list boxes on a standard form - one listing cities, the other capitals.
If the user selects the correct combo, and presses a check button, a standard msg box is displayed with congrats etc.
If the user selects the wrong combo, another msg box is displayed with a Yes No selection, to the question of if they want to have the correct answer selected for them.
Now, I've got everything working apart from this last part - having the correct answer selected. Here's the snippet of one of the If parts.
Just a word of warning - yes, it'll obviously be 'messy' and probably 'wrong' to anyone who is even half decent at VB.NET, but I've only just started, and it works for me, so that's all for now :-)
ElseIf lstCountry.SelectedIndex() = 4 Then
If lstCapital.SelectedIndex() = 0 Then
MessageBox.Show("You got it right!", "Correct!", MessageBoxButtons.OK)
Else
[Code]....
Just want to stress again - I haven't given up at the first hurdle - I've been trying to figure this out for well over an hour (probably more) now. Whatever combination I try seems to be wrong - when I press Yes it just stays on the currently selected item.
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Jul 20, 2011
I have a single Row in DataGridView which shows different results for the selected Oids..The problem is that the next result replaces the first one in the same row..Is there any way to get next result in next rows so that DataGridview can show previous results also..my datagrid is not bound to any data source.[code]...
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Jan 3, 2010
I'm trying to get the row number of the result row but I don't know the exact syntax.
For x = 0 To BDataGrid.RowCount - 1 'sort thru datagridview
If BDataGrid.Rows(x).Cells(0).Value = newID Then 'if result found
'get row number of result row???
End If
Next
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Jun 6, 2010
in visual basic in studio if this is used for giving a message MsgBox("hello", 4, "status")how to manipulate the result yes or no from the msgbox like this should happen if the user gives no and this should happen if no
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Apr 16, 2010
I am using vb.net 2010 with access 2007. everything works fine in XP, but when I switched over to windows 7 I did not proper result some queries here is my query: Select * FROM tblname WHERE fordt=#13-12-2010#It shows result in access as well as as in form.I get value from form in MM/dd/yyyy fo
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