how to perform the database operation such reading data and using them for comparison within the VB programming..
Please guide me with explanation as i have very little knowledge regarding the database operation...
i am using VB.Net 2008 as frontend...and MS SQL Server 2008 (express edition ) as back end...
Dim Conn As New ADODB.Connection
Dim rs As New ADODB.Recordset
Conn.ConnectionString = "Provider=Microsoft.Jet.OLEDB.4.0;Data Source=" & "C:Documents and SettingsUserDesktopContribucionescontribuciones.mdb"
rs.Open()
rs.Open("SELECT * FROM master")
rs.MoveFirst()
TextBox1.Text = rs.Fields("sueldoanual").Value
I have this error
The connection cannot be used to perform this operation. It is either closed or invalid in this context.
This error occurs when I want to add my app to the startup keys
My.Computer.Registry.LocalMachine.OpenSubKey("SOFTWAREMicrosoftWindowsCurrentVersionRun", True).SetValue(Application.ProductName, app)
[code].....
I'm trying to use DataView.Rowfilter and I'm getting an exception which says "Cannot perform 'Like' operation on System.Int32 and System.String".
Here's the code...
Dim str2 As Double = CDbl(searchSTR)
Me.shipperDV.RowFilter = fieldName & " LIKE '*" & str2 & "*'"
I'm using this class to try and impersonate a user on a remote machine.[code]....
However, it fails when trying to open the registry hive with an "Attempted to perform an unauthorized operation" error.I know the password is correct so can someone tell me what might be going wrong?
this is the code have written am unable to perfrom the log in operation.[code]
View 1 RepliesI want to make an application in VB.NET and I want this application to work as follows, There will be an array of items on which I want to perform a specific operation (MyTask), with the help of multiple threads.For example, say, the array is holding 12 items in it, and I want to create 3 threads to do the work,
Thread 1: Reads the first item from the array and goes to perform the specific operation (MyTask).
Thread 2: Reads the second item from the array and goes to perform the operation MyTask
Thread 3: Reads the third itm from the array and goes to perform the Mytask.
Now once Thread 1 completes the operatin MyTask, I want to assign 4th item from the array to the Thread 1 to continue the process.Once Thread 2 completes the operatin MyTask, I want to assign 5th item from the array to the Thread 2 to continue the process and so on... until all the items from the array is processed. Also, the function taking 5 arguments out of which 4 arguments will be same. Only one argument will vary and it will take the keywords one by one as input parameter.
I have a list of items and wish to set one of their properties to a certain value:
applist.ForEach(Function(x) x.PrePaidTypeID = CInt(DBEnums.PrePaidType.NoPrepay))
...but we think this just does a boolean comparison. Is there a way to force VB to assign the integer value rather than compare it?
currently i am working on a project in which i am using datagridview control. if I enter key value in cell than remaining data of that particular row fetch automatically from data base. how? how to delete as row in datagridview? how to update a row in datagridview?
View 5 Repliesi am trying to write a program which reads a data from the database and perform some calculations. what i am intending to do is when a user selects an item from a listbox and clicks the submit button the program, calls a function to calculate using the value stored in the database and display the result in a textbox.the problem is i cant store the data retrieved from the database into a variable so that the calculations can be done. i am using vb and microsoft sql server.can anyone tell me how do i store the data retrieved by the query into a variable.
View 12 RepliesWhen I try to run my DLL in Autocad, I got the message below.Application attempted to perform an operation not allowed by the security policy. To grant this application the required permission, contact your.I know there are many threads on this error, but Im not sure about one thing.Can I resolved this on our FilesServer or I have to do something on each computers that will use the DLL ?
View 3 RepliesHow to perform add, edit, delete in a dataset that will update the database as well?
View 1 RepliesI have an Access database that has thousands of records. The fields in the database are EMPID, FIRST, LAST, JOBTYPE and PAGES. I would like to know how to loop through the data table and for each individual EMPID to calculate the sum of the PAGES for each JOBTYPE.There are four JOBTYPE's: "E", "K", "O" and "R".Here is some
Dim WebAllEmployeeQuery As String = _
"SELECT ELPallEmployees.[EMPID], ELPallEmployees.[FIRST], ELPallEmployees.[Last], ELPallEmployees.[JOBTYPE],
[code].....
I wrote the code below which calculates the length of a line on the form and save record. An error occurs when the programme tries to save the record. It gives me "Cannot perform '=' operation on System.Int32 and System.String" error. I checked the data type of "ID"(int), "Microscope"(Varchar), "Magnification"(int) and "Calibration"(Decimal), and they are fine so far as I know.
Code:
Private Sub btnEnd_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnEnd.Click
'Check if the length textbox is not empty
[Code].....
Here is the code I am working with, everything works fine up until last line then i get evaluate exception unhandled "Cannot perform '=' operation on System.Int32 and System.String." My eyes are going blind trying to figure out whats wrong, if I understand correctly it cant count system string and REO is a string value.
The thing i have done this before ,count that is. I know you cant average strings and some other function but i have been able to count.
d Dim comm As New OleDb.OleDbCommand("Select * From " & Me.OpenFileDialog1.SafeFileName & " Where Status <> 'S'", con)
Dim dalist As New OleDbDataAdapter(comm)
Dim comm1 As New OleDbCommand("SELECT * FROM " & Me.OpenFileDialog1.SafeFileName & " Where Status
[CODE]...
For this code, I'm trying to have it pull the ID of the doctor from the database and only show their patients. I keep getting this error when I try selecting one from the list though, right at the red section.
[Code]...
I get an error "Cannot perform '=' operation on System.String and System.Int32" on the following code:
VB.Net Code:
Public Sub board2_OnGameWon(ByVal sender As Object, ByVal e As EventArgs)
If Not board2.isCheated() Then
Dim time As Integer = board2.getGameTime()' I have tried changing this to String
[code]....
The exception is in the lines where I 'Dim betterScores' above. The idea is that when the player wins a game their score is placed and held in the betterScore variable. It is then written to an xml file later on.
I have a Difficulty Menu item (System.Windows.Forms ToolStripMenuItem) containing 4 choices, 3 of them work but one doesn't. The one that doesn't work is "1.0 (Normal)" and in the Sub New is "adjustDifficulty(mnuDifficulty100)"I have copied some other subs that are associated with this code below.
VB.Net Code:
Public Sub New()
' This call is required by the Windows Form Designer.
InitializeComponent()
[code]....
how can i display data from a sql database in a listbox?
View 2 Repliesheres the problem lets assume i have a label1 which its text is "(y+1)"i defined an integer, lets assume its x i made some operations up and lets say there can be diffrent results and i want to replace y with that math ops result and then define x as it writes in label1..
[Code]...
Private Sub frmAttendace51_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
'clear data set of any existing data
objDataSet.Clear()
'fill schema
[Code]...
reading and modifying data from database
View 4 RepliesI made a query in MS Access using fields from multiple tables. I want to display stuff from it into a listbox on the form and then I need to save stuff back too it also. But I'm obviously doing something wrong cos I keep getting the error: "The Microsoft Jet database engine cannot find the input table or query 'Today'. Make sure it exists and that its name is spelled correctly." [code] Also, I have written further down objDataSet. Tables("Today's Absentees") and "Today's Absentees" is a query not a table, what needs to be written instead?
View 3 RepliesHow to read data, submit queries from vb application to a remote machine running sql server. note: I have created a complete functional version of a stock control system with the database residing in the local machine. I just need the basic concept of interacting with remote databases that's all. Do we have to use sockets to read/send data ?
View 2 Replies1) i want to make my login page (which talks to a sql table called logins) my first page and it authenticates to that database and doesnt let you in until correct credentials are entered. ? not sure how
2) I have a Checklistbox that is populated with names - ( i want to be able to populate a database called members with those names(Firstname & Surname Only) and from a New members form populate the same members details into the members database this time including address email tel etc etc ....
3) create a delete button that will delete the information from the database and from the checklistbox1 (this is in case the member leaves the club).
4) how do you create trial versions keys etc ...
5) change a progressbar timer to last an 1½ and show hours minutes seconds but once the button is hit to stop the timer it automatically resets to zero.
I'm reading data from a .mdb access database to a form in my app. However the text is sometimes becoming scrambled as shown belowDatabase:Quote:The resistance of a 2.5mmonductor of length 8m and resistivity p = 1.72
View 6 RepliesI get this error when i request the 'SelectedItem' property of a standard .NET ComboBox control from a BackgroundWorker control.
I know why this exception is raised, however, i thought that read-only operations to controls from different threads were safe?
I know i can turn this off using Form.CheckForIllegalCrossThreadCalls - but i want to make sure that readonly calls from non-ui threads are actually safe or not?
I'm trying to handle DBNull exception while reading data from database. It's my code:
...
Dim SQLRDAs SqlDataReader
...
val1= GetStringFromDB(Trim(SQLRD("Name")))
val2= GetStringFromDB(Trim(SQLRD("Level")))
[Code]...
But still I get Conversion from type 'DBNull' to type 'String' is not valid. error.
I have login system and also I know how to get 1 exact row from mysql but how can I create a table which will be filled with values from mysql table?
[Code]...
I have some trouble with opening a excel sheet and getting some data out of it.
I want my program to have a button, when pressed, gives a "select excel file" popup and then load the data from some cells into my sql database.
So, when opening a excel file the program should get the data from cell D3 to D8 and put that into the sql database.
I now have the following, but that will only open the excel file.
Public Class Form1
Dim oConn As ADODB.Connection
Private Sub ConnectDB()
[Code]....
I have created a application in vb.net. I am using Web Browser control in it.With this Web Browser control I open an URL and tries to Download something, it will populates an dialog for "File Download" to Open/Save/Cancel for the file..I am downloading the .ZIP file, and it will not show the checkbox for Automatically Do.Is there any way to perform the Download operation at the backend, means it will not ask me for such options.
View 2 Replies