I have a small program which loops records of one datatable against records of another datatable. I use a function that places two fields of the 2nd DataTable into an array. The problem I have is that if there is a NllValue in one of those fields I recieve an error message unable to cast Null to type Double.
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What is the simplest/cleanest/easiest/best way to handle Null value of a Strongly Typed DataSet in the following case :A base class has a Nullable value that is set through it's constructorThe derived class's constructor has Strongly Typed DataSet Row as parameter and it Throw exception when accessing a null value.Here a simplified example to demonstrate the problem I'm facing. Any resemblance to your code is purely coincidental.
Public MustInherit Class BaseClass
Private _Number as Nullable(of integer)
Public Sub New(Number as Nullable(of integer))
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I'm reading a xml document via a text reader, this is my code
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I have the following Stored Procedures create or replace PROCEDURE WEB_AC
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First one: At some point in the application I have the valor parameter (of the visual Basic Function) as a string with spaces that is something like "some string with spaces". When this happens, the stored procedure don't update the table. If I execute the SP directly in the DB (with SQL Developer) all works fine. I know it has something to do with the string missing some quotes(') but I haven't make it work yet. Some ideas on this?
Second problem: Sometimes, when debuging the application, if I interrupt the execution, I start getting the ORA-24338 'statement handle not executed' error for hours every time I try to execute it again. I believe it has something to do with an open transaction. But honestly, as I'm new in working with Oracle, I really have no idea what the problem could be.
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I have a filesystewatcher object. On it`s event it runs a procedure which fills a treeview with a data. I had problems with treeview methods, but when I run them using invoke method everything is ok. But I still have one problem. When I load the form for the first time, everything works fine. But, when I then close the form (me.dispose, me.close), and load it once again, when Filesystemwathcer start the procedure i have an exception "invoke or begininvoke cannot be called on a control until the window handle has been created" trying to run a treeview.invoke method?
View 9 RepliesThere are three forms on this application and they are a MDI Frame(frmMain) and two child forms (frmSearchEmp, frmEmpDetail).
What I am trying to do is opening a "frmEmpDetail" by executing "CallEmpDetail()" on "frmSearchEmp".[code]....
In vb.net and made a proj. in vb2005. but when i try to load a particular form(opens up in a mdi container like all others in the project) , an error-error creating windows handle pops up, the line is frmadmn(the form).show
What shall i do? i read a lil on the net about too many handles, user objects etc. but the stats of my proj. at the time of error are-handles-350,threads-17,user objects-235 gdi objects - 159. have these anything to do with the prob.. then what should i do..? i read about the dispose command also about how to use it ? what to dispose...?
I get this error as below when I open my "frmAddPrivate" more than 5 times. How I can overcome it?
View 5 RepliesI've a little program that has got tabControl with 2 tabs - "results" and "log". My idea was that when an error occurs the tab will switch automatically on tbLog to show what the problem was. Most arguably the problem is in threading. This is the code that..I use:
Dim thread As New Thread(AddressOf ExecuteQuery)
thread.Start()
ExecuteQuery executes the query and I'm making an error deliberately to see if I'll be automatically switched to the log tab which is in Try-EndTry procedure:
tbGrid.SelectedTab = tbGrid.TabPages(1)
The program indeed switches to tabLog (which is number 1) but I don't see any controls on it (txtLog), then when I'm trying to switch tabs a couple of times I get "Error creating window handle in a thread". I read other forum threads about it where people as how many controls do they have in their programs but my program does not exceed 70 controls on a form.
I show a waiting form (saying "Please wait...") on a different thread when there is long-running code in some forms (for example, during data loading). I show the form like this:
m_PopProcessingThread = New Thread(New ThreadStart(
Sub()
m_PopProcessingForm = New WaitingForm(m_Message)
Application.Run(m_PopProcessingForm)
End Sub))
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The stack trace points to the part of code where I hide the form. How could the handle not have been created, when just before the Invoke call, I loop until said handle is created?
I am using a Thread object to perform a function. This function performs a task and displays its progress in the gridview (like adding rows changing text etc )
The reason I am using a thread for this function is that there is a cancel button on the form. While the task is in progress, user can click on cancel to abort it.
Private Sub BtnStart_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles BtnStart.Click m_Thread = New System.Threading.Thread(AddressOf myfunction) m_Thread.Start() End Sub
The function works fine and thread is completed. But calling any method of datagridview after thread is completed ( outside the worker thread ) generates an error- "Error creating window handle".
That's probably because i am not using the invoke method of datagridview for calling its methods or readingwriting properties Do i have to create separate delegates for all the methods properties used in the function ( worker thread)
I have couple of questions with datagridview 1.How to handle the Enter-Key when the user edited the columns value.?I mean, without changing the columns values we can suppress the enter-key by following. No problem. It's working Fine.
Private Sub DataGridView1_KeyDown(ByVal sender As Object, ByVal e As System.Windows.Forms.KeyEventArgs) Handles DataGridView1.KeyDown
If e.KeyCode = Keys.Enter Then
Dim numCols As Integer = DataGridView1.ColumnCount
Dim numRows As Integer = DataGridView1.RowCount
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But after if I select any one column & changed the values then if I press <Enter> it's moving to next row. But I want to move it to next column..
2. With Datagridview - I have a column for date. and it's defaut format is mm/dd/yyyy. But Iam looking to read the date by "dd/mm/yyyy" format. Also if the user feed wrong date format then it has to display my Error message. "INVALID DATE"
I'm currently developing a little hobby project to display health information in a game on my G15 keyboard through VB.NET. When I use ReadProcessMemory via an API call, it keeps returning zero. The MSDN documentation referred me to use the Marshal.GetLastWin32Error() call to find out what is wrong and it returns 1400: INVALID WINDOW HANDLE.
I am now confused about whether the first argument of the function wants a window handle or a process id. Regardless, I have tried both with FindWindow and hardcoding the process id while the application is running (getting it from task manager). I have tried three different games, Urban Terror, Grand Theft Auto: SA and 3D pinball for windows, getting the memory addresses from an application called Cheat Engine; they all seem to fail. [Code]
I'm in the process of converting a VB6.0 application to VB.Net (2008 Express). I have a MDI parent form, I'll call mdiBackground, and 4 MDI child forms, frmStatus, frmShow, frmQwerty, and frmSentence.The layout is as follows:mdibackground - has the menus at top and is a container for the child forms.frmSentence - appears at the top frmShow & frmQwerty - appear at the left and when one is closed the other one is in the same position.frmStatus - appears at the right, it has buttons which control when frmShow and frmQwerty are to appear I have a couple of regular forms that act as dialog forms. The Me.Close() works fine on these.
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I have a section of code that will compile perfectly using VB Studio 2003, but it throws a InvalidCast Exception under VB 2005/2008. The code throws an Invalid Cast exception at KeyHandle = e(field.GetValue(KeyToMonitor) line below, and as far as I can tell it is because the variable Field is passing the string Microsoft.Win32.SafeHandles.SafeRegistryHandle rather than an integer. Is this because of safe keys in VB 2005 and 2008?
how to call the handle of the registry key opened in a way compatible with Safe Keys? I'm using the code to notify when a registry key is changed using RegNotifyChangeKeyValue.
Private Function WaitForChange() As Boolean
Dim notifyEvent As New Threading.AutoResetEvent(False)
Dim KeyHandle As IntPtr
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I have a program which uses TcpClient, the issue I'm having is how do I construct the packets when some of them come in seperate parts. For example, If I receive 5 packets, 2 of them are fine, but the other 3 have come in seperate parts when it's suppose to be a whole packet. How can I handle this?
View 5 RepliesI don't know how much sense the title makes, but let me give you an example:If you've used Xfire, you may have run across links that allow you to modify things in the program such as your status.This is an example of a status changing link:xfire:status?text=I%20love%20Donkey%20Kong%20Jr.And your status will change to "I love Donkey Kong Jr.
View 4 RepliesI'm using this code to get the StartMenu handle:
Declare Function FindWindow Lib "user32" Alias "FindWindowA" (ByVal IpClassName As String, ByVal IpWindowName As String) As IntPtr
Declare Function FindWindowEx Lib "user32" Alias "FindWindowExA" (ByVal
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But it doesn't seem to work, I can get the taskbar handle but not the start menu handle
I have the following code to handle keypresses on the form:
Private Sub Form1_KeyDown(ByVal sender As Object, _
ByVal e As System.Windows.Forms.KeyEventArgs) Handles Me.KeyDown
Debug.WriteLine(e.KeyCode)
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The first time I press any of the arrow keys the code is not executed and a NumericUpDown(NUD) on the form gets the focus. The rest of the times the arrow keys are pressed everything is fine, until I click on a button. Then the problem repeats, focus NUD, then fine.
i've created an array of checkboxes like this
CheckBoxesArray = New CheckBox() {CheckBox1, CheckBox2, CheckBox3, CheckBox4, CheckBox5, CheckBox6, CheckBox7, CheckBox8, CheckBox9, CheckBox10, CheckBox11, CheckBox12, CheckBox13, CheckBox14, CheckBox15, CheckBox16, CheckBox17, CheckBox18, CheckBox19,
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what's the best way to handle the updates to the database.For example i have one datagridview that's binded to a datatable (with two fields, id auto incremented and a varchar). The user can do all the operations Insert, Update, Delete.If i insert one row (only the text) and call the update method to save the changes to the database, and after that remove the same row and call the update method the adapter will throw a exception because it didn't update the datatable with the value of the id. So the best way to do this is always calling the fill method after every update?
View 22 RepliesI have a DLL that copies an Access database, opens it, reads it, and then closes it. The second time through it is unable to copy the Access DB because the EXE has an open handle to it. The EXE does not reference the Access DB at all, it just has the open handle because it calls my DLL. After I close the DB, I would like to terminate the EXE's handle to the Acess DB. BTS - I wrote the DLL and it is my Access DB. Another company wrote the EXE and I can not make any changes to it.
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How would I use FindWindow to get the handle to a textbox on my form?
View 5 RepliesI wrote an application to handle a joystick with directinput. It works fine if it uses the handle of the main window but it doesnt happen the same if the handle is the one of the component that contains the joystick's operation.
I mean:
main form handle: 15
component handle (which is inside the window and the joystick needs the focus of this component to work): 25
It always work if the handle i initilizate the device is the main form (15).How can i use only the handle of the component?
We have a VB 2008 Windows application that is deployed on several hundred computers. For some strange reason only 2 computers out of the hundreds are experiencing the "Error creating Window handle" error. It is happening more consistantly on one machine than the other. Any idea what might be causing annoying error on such a limited basis? (It's a Windows XP machine that it is happening on. That's all the info I know regarding the machine currently.)
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when the Internet it's ok,this code it's okay,too.but when the Internet it's not connect or the webside server it's so busy,it's going to error,it said "Webexpection it's not handle".what should I do?
I have a table called ConcernedParty. It has an ID field, description and a TypeID which is a foreign key to the pk TypeID column of a table names ConcernedPartyType.Now i'm creating two classes. One for each table. In my ConcernedParty class I have and ID, Description property etc. how must I handle the TypeID in my ConcernedParty Class.
Do I declare it as:
Public Property TypeID as ConcernedPartyType
Or
Public Property TypeID as Integer
Is it possible to send keys to a specific windows handle without having to bring that window to focus?Right now I have the following code almost doing the trick:
Private Declare Function FindWindow Lib "user32" Alias "FindWindowA" (ByVal lpClassName As String, ByVal lpWindowName As String) As Long
Private Declare Function SetForegroundWindow Lib "user32" Alias "SetForegroundWindow" (ByVal hwnd As Long) As Integer
Sub SendKeysToApplication(ByVal AppTitle As String, ByVal Keys As String)
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It will bring the windows calculator window to the top and set the value "1" on it.Is it possible to send the keystroke without poping the window?
How to find window handle by its position?
View 13 RepliesIs there a way I can catch and handle two different exceptions within the same exception type? For example:
Try
' My code
Catch ex As System.Net.WebException
End Try
I have 2 different exceptions that are System.Net.WebException. I want to handle them different ways. Problem is the catch block above catches them both. Is there a way I can determine if which of the two it is and handle them differently?