C# :: Database Remains Empty?
Jan 15, 2012STEP 1: I backup the database using this code snippet (It works fine)
Public Shared Sub BackupDatabase()
Dim sConnect As String = My.Settings.LICConnectionString
Dim dbName As String
[code].....
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VB 2008: Print Preview Remains Empty?
Apr 19, 2012I'm trying to understand why my print preview is not showing the contents of the file (I've double checked that the file is in the correct directory and is not empty)
Imports System.IO
Imports System.Drawing.Printing
Public Class Form1
[Code].....
Database Updating, But GridView Remains Unchanged?
Oct 12, 2011I've got my code to delete rows out of the database when the user clicks on the Delete button in my GridView, but the GridView isn't updating to reflect the new data changes.
Here's my code:
<asp:GridView runat="server" ID="grdQuestions" AutoGenerateColumns="false" Width="100%" CellSpacing="10"
PagerSettings-Visible="true">
<HeaderStyle CssClass="aspNetHeader" />
[code]....
EDIT 1:Did some stepping through the code and found that e.CommandArgument is not getting a value in grdQuestions_RowCommand
EDIT 1 (Revised):The fact that e.CommandArgument wasn't getting a value was my mistake. I'd changed the way it's value was being assigned without removing the previous method.The code runs through grdQuestions_RowCommand and then goes into grdQuestions_RowDeleting and then executes GetModuleData.I have a feeling that to view changes to the grid, a PostBack might be required, but I've removed all DataBinding to an If Not IsPostBack Then block because the alternative caused problems with the DropDownList whose selection is used as a reference to populate the grid (ddlModules selected the Module whose Questions will display in the grid).
Copy Opened Database - Application Gets It's Data From A Mdb-file And The Connection Remains Open As Long A Person Works?
May 14, 2010The fact is I'm making an application, which users can install by using a Setup file...once installed the data in the database can be updated by a centralized server. To do this, they can insert a DVD/CD-ROM and export the necessary data towards it. I need to do it that way, because some of the users who really need this data will be using stand alone computers.The application gets it's data from a mdb-file and the connection remains open as long a person works with the application (maybe not the best way to do, but I know :-) )...when the user uses the application, he can perform an export...this exports the .ini-file and pictures (which works fine), but he also needs to export the mdb behind the application...I already tried connection.close() before and connection.open() after the System.IO.File.Copy...but that doesn't seems to work.
View 2 RepliesGetting Error When Database Is Empty
Oct 7, 2010Code:
Private Sub RandomID()
Dim conn As MySqlConnection
conn = New MySqlConnection
conn.ConnectionString = cnString
conn.Open()
[Code] ....
I am getting error here
LastID = comm.ExecuteScalar()
When db is empty, but if db has records it is working fine.
How To Identify Empty Records In A Database
Aug 27, 2011I am a newbie using Visual Basic 10 (Visual Studio 2010) and I am having a hard time working with my database. I have a table, let's say, TableEmployee with Fields Name and Position. On the Position Field, some of the records there were empty.My table is displayed in a datagrid and what I want to do is to insert a code that will identify whether the record under the position field is blank/empty and if that condition is true then display a messagebox that says "the particular record is empty"
View 7 RepliesMessage If All Textbox Is Empty In Database
Jan 30, 2009Adding a records with ms access.if my form load is empty in my textbox and press ok button will show a message box "Records Failled".I'll try to run it and i got an error "Data type mismatch in criteria expression." [code]
View 10 RepliesShow A Message If Database Query Is Empty?
Apr 4, 2011I have the following form and I'm trying to add a error to the page that if the recordset = 0 then there is a message on the web page stating that there were no results. What's the best way to do that?
Imports System.Data.SqlClient
Imports System.Data
Partial Class _Default
[code].....
Sql - Write Database As Null Instead Of Empty Strings?
Jan 12, 2010How can I change the following code to write to the database null instead of empty strings?
Public Sub SetChangeRequest(ByVal referenceLeaseID As Integer, _
ByVal referenceCustomerID As Integer, _
Optional ByVal custUnitNum As Object = Nothing, _
[CODE]...
Insert NULL Into Database If Form Field Is Empty Using ASP.NET & VB?
Jan 18, 2011I have a form and stored procedure that inserts the data from the form. It works fine except that if a field isn't filled in it doesn't insert a NULL into SQL it inserts "".
I've tried a few different ways but none seem to insert NULL, the one below still inserts "", can anyone point me in the right direction?
Here is the required part of the code, if you require more just let me know.
Dim rdr As SqlDataReader
Dim cmdInsert As SqlCommand = New SqlCommand()
cmdInsert.CommandText = "spPersonalDetailsInsert"
[Code].....
So if I enter nothing into address1 field it should write NULL to screen but it always writes NOT NULL. What does an empty form field equal? in classic ASP it was always "".
Skip Empty Database Fields And Goto Next Step
Dec 4, 2009How to tell the program that if the field is empty to skip it and go to the next step. I have tried IsEmpty (but it tells me the variable IsEmpty was not declared), I have tried to use different If statements but in most cases I get the message
"Conversion from type 'DBNull' to type 'String' is not valid."
I tried using an integer variable and setting it to
'Test = CStr(dt.Rows(I)("socSecNumber")).Length'.
It works for the first step (which makes sense b/c socSecNumber is never empty), but when I set the 2nd and 3rd ones
(TestFName = CStr(dt.Rows(I)("firstName")).Length TestLName = CStr(dt.Rows(I)("lastName")).Length If TestFName > 0 And TestLName > 0 Then...)
Then I am back to getting the message
'Conversion from type 'DBNull' to type 'String' is not valid'.
I do not know anything about recordset and when I did try to use it it displayed the message something like 'get and set are no longer allowed'.
The entire function is below:
Private Sub BtnCreateLetter_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles BtnCreateLetter.Click
Dim SSN As String = TxtBxSSN.Text
Dim dt As New DataTable()
[Code] .....
Is it possible to include something in the SELECT from table? Such as:
"SELECT * FROM" & Students & "WHERE" * NOT DBNull
or
I do not know if it is possible to use variables in the SELECT from table code but if it is I thought perhaps could make a variable named FieldContents and pass it to a function that would do something like:
"SELECT * FROM" & Students & "WHERE" * FieldContents LIKE '[A-Z]'
Databound Radio Button Class When Database Table Empty
Apr 13, 2009The problem I have is that many times, the dataset that this control is bound to is empty. Therefore, the user continuously gets an error saying that one or more fields is missing. When I debug the code, I can see the code in the class loop through all of the radio button controls on the form. Since none of them match the field from the database, the code throws the error. I assume the code expects a match.
Should I modify the class to handle the case when there is a DBNull value? If so, what would be the best method? Or should I approach this situation in a completely different manner?
Public Class myGroupBox
Inherits GroupBox
Private _myTag As String
[Code]....
Forms :: Get The Message That The Local Database Is Empty But The Program Still Runs?
Dec 27, 2011I'm having an issue with the startup of my build app with vb2010.Let me explain what the situation is at the moment.
I have a form and a splashscreen. I use the application events (startup event) to check if there is a network connection, if so the splashscreen will run and it will check if the database is available, if this is the case, it will copy the online database to the local ms access database.If the startup check of the network is false, it the user gets a message that there isn't any network available and the program will try to run normal, then when the user clicks the ok button of that message, it will check if the local database has any records. If so the splashscreen will run and the program starts normal (without copy the database, because there isn't any network available).The issue that I am having is, that when there isn't a network connection and the local database is empty, (I do get the message that the local database is empty), but the program still runs, while it should exit.Here is the code of the application event:
Protected Overrides Function OnInitialize(commandLineArgs As System.Collections.ObjectModel.ReadOnlyCollection(Of String)) As Boolean
Me.MinimumSplashScreenDisplayTime = 5000[code]......
Asp.net - Why Does SelectedIndex Not Change, Remains As -1 Even If Changed On The Website
Jun 15, 2012Code for button:
Protected Sub btnAdd_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles btnAdd.Click
Dim li1 As ListItem
Dim addList As New List(Of ListItem)
[code]....
Updates are happening on the load of a dropdownbox This has something to do with autopostbacks and the page load I think, can someone please help When I click the add button even if I have selected an item in the listbox, it will always return an error message. I don't think the listbox changedselected item is firing.
Cannot Terminate Application - Process Remains Active
Nov 6, 2009I'm having troubles with terminating an application. When I close the main form everything disappears but the process remains active. I think I know the cause, a certain activeX component will not release properly. As soon as I create one, I can't close normally...
dim someActiveXcomponent = new X()
...
<formClosing>
someActiveXcomponent = nothing
GC.Collect()
GC.WaitForPendingFinalizers ' here it hangs
Probably a bug in that component, but the problem is that I don't have much of a choice, I'll have to use that component for now.
Calling
System.Runtime.InteropServices.Marshal.ReleaseComO bject( myObject )
will kill the reference and now the application closes properly.
Port / Socket Remains Open After Crash
Aug 14, 2009I'm having this problem with a networked app in vb.net. If the program exits normally the port closes fine, however, if it crashes sometimes it remains open and I am unable to close it. The next time I run the program it is unable to open the port because it is already in use. Here's the exception: 10048: Only one usage of each socket address (protocol/network address/port) is normally permitted on how I can reclaim this port, or how I can close it? I tried using the reuse address socket option
[Code]...
Return Amount Of Money That Remains At End Of Each Year
Sep 9, 2009"Create an application that will return the amount of money that remains at the end of each year."
Initial Deposit: 5000
Withdrawal Amount: 500
Number of Years: 4
The following is code for a CalcButton:
Dim intDeposit As Integer
Dim intWdrwl As Integer
Dim intRemain As Integer
Dim dblRate As Double = 0.05
[Code] .....
I'm supposed to populate a multi-line textbox in one calculation, so that it looks like this:
1 $4,725.00
2 $4,436.25
3 $4,133.06
4 $3,814.72
Instead, I get:
1 $4,725.00
2 $4,725.00
3 $4,725.00
4 $4,725.00
I think the intYrs needs to go somewhere in the formula after all the TryParses.
Splash Screen Remains Open Behind Login?
Dec 13, 2011I have a Main form, a Login form and a Splash form. In the project settings I've set the Splash screen.
System.Threading.Thread.Sleep(3000)
Login.ShowDialog()
If Login.DialogResult <> DialogResult.OK Then
[code].....
Textboxes Cleared But Memory Remains Stored
Apr 28, 2009I am working on completing the Clear event for Button Clear Sub routine. I have been able to clear the textboxes with the code I already have. However, in playing with the application, I noticed that the memory remains stored somewhere in the program. How to both clear the textboxes, and clear the memory?
Code
Private Sub btnReset_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnReset.Click
txtTestScore.Text = ("")
lblNumberOfScores.Text = ("")
lblAverageScore.Text = ("")
lblBestScore.Text = ("")
txtTestScore.Focus()
End Sub
.net - File Remains Locked Even After Calling Filestream.close?
Feb 10, 2010In my application, i am downloading file from DMS system to my server. Once the file gets downloaded, on some environment, the iis keeps lock of the file and when the application tries to redownload the file and put the file on same location, an error is generated that file is being used by another process. Following is the code :
[Code]...
Adding Flash Object Remains Plain White
Jul 30, 2009I've added reference to Flash object. Then dragged AxMacromediaFlash to form. [renamed Flash1]. Even after setting Flash1.Movie="file.swf".
it doesn't start playing ! I tried, loadMovie,Play,MovieData etc etc.. nothing works. There's no error, no warning, nothing. That Flash object remains plain white. am not using try catch too. I'm on Vista Home Premium 32bit, Flash player 10, Flash ActiveX version 10. Tried re-installing player, activeX. its just not working! : any known issues am ignoring here? and same file works fine if I drag it in IE. and if I check Flash1's state, it shows playing.
ToolStripDropDown Menu Remains Open Even On Click Of Other Windows
Sep 3, 2010I am using a toolstripDropdownbutton on the toolstrip to populate the
menuItems.The toolstrip is on the customtaskpane of the window.
Problem comes when the focus is on the customtaskpane, user opens a dropdown menu and without selecting any menu from the dropdown click on the other part of the window. The dropdown remains open and even the user switch to other window it remains open and does not hide. It only hide when user click on the dropdownbutton itself.
Note : I had set AutoClose property to Flase
VS 2008 Application Remains Open After Closing All Forms?
Dec 23, 2009my application will remain open after closing every form. This is a recent issue in previous versions my application would close. I call dispose(true) on all form closing/closed events. (some forms require it on closing instead of close because of some custom made classes.)?
View 5 RepliesScript Doesn't Properly Close Word, And It Still Remains Open?
Nov 20, 2011Basically my script doesn't properly close Word, and it still remains open. Then when I try to run the script again it says its Read-only as its opened..What I need it to do is - put the TextBox1 info onto the DOC - and print it. I don't want it to save, as it's a template. I've tried saving it somewhere else as a "temp" to get rid of this read only but it still doesn't work.Another issue also is that it's trying to close the document before the printing dialog disappears, so I've had to put a timer
Public Class Form1
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
Dim pName As String[code]....
VS 2008 DataTable.Merge(AnotherDataTable) - RowState Remains Unchanged?
May 25, 2009I want to compare differences between two tables in my database with identical schemas.
vb.net
DataTable1.Merge(DataTable2)
Dim changedRows As DataTable = DataTable1.GetChanges
'changedRows is always Nothing. Why???
The DataTable1 is updated with rows from DataTable2 correctly. i.e. missing rows are added and datarows that don't match are updated. But the RowState of each row is still unchanged. I need to have the rowstate (added/modified/deleted) so that I can update the database table.
Datepicker Does Not Disappear But Remains Visible Underneath The Date Passed And Showcalendar Text
Mar 13, 2009I have noticed that hwen i set the datetime programmatically on the wpf datepicker the writing "show calendar" does not disappear but remains visible underneath the date passed?is there a way to solve this problem
View 3 RepliesExcel Remains Running As A Background Process After Performing Mail Merge And Exiting?
Aug 26, 2009I have a spreadsheet that contains details of change requests; one row per request. This information needs to be copied into a Word form for sending off to our customer who then completes the response section. To speed up this process I have written some code that utilises the mail merge feature of Word and merges the relevant info from the spreadsheet into a Word form. This runs from Excel when a button is pressed.The problem comes when I go to save the workbook and exit Excel; it stays running in the background as a process in task manager.
[URL]
I'm fairly sure it has something to do with the merge code itself but my knowledge of VB is enough to grasp what is happening but not why it is happening. If I open the Word doc that has the merge fields in it, then open the spreadsheet that houses the info Excel says the workbook is already open.
DataGridView - Convert Nulls To Empty Strings And Display It In The Grid As Empty Strings
May 14, 2009I have a DataGridView that has some columns with dates. It binds to an in-memory Datatable which gets loaded from an string array of data passed back from the backend Some of the rows returned have nulls for the date columns. Solution 1: If I define the Date column in the DataTable as "string" I can easily convert those nulls to empty strings and display it in the grid as empty strings (desired results). However, if the user clicks on the date column header to sort by date, it doesn't order the rows as you want. You get a purely string sort order. Not acceptable
[Code]...
Collapse Treeview - Collapse My Tree Then My Last Viewed Document In The Web Browser Remains Visibe
Aug 3, 2010When I select a node in my treeview I have no problem seeing them in my web browser.
My problem is that when I try to collapse my tree then my last viewed document in the web browser remains visibe.
How can I ensure that when I collapse my tree my web browser will also become totallt empty?
Nothing Equals String.Empty, Null Does Not Equal String.Empty?
Jun 28, 2010This must've have been asked before but I couldn't locate it. In a mixed code project (VB and C#) we were debugging some old Visual Basic code where a statement as follows could be found:
If Request.Params("xxx") <> "" Then
'do something
I considered this a bug as Request.Params could be null, in which case the statement would've become false which wasn't the idea. So I thought. I just found out, -- probably for the tenth time and I will keep forgetting -- that the following two statements are not equal, while Nothing in VB should be equal to null in C# (thought I):
if(String.Empty == null) // always false
If String.Empty = Nothing Then ' always true
Should I dismiss this as a typical Microsoft backward compatibility effort, or should I consider this a huge error in the VB.NET compiler? Does anybody know the Microsoftean opinion on this oddity?