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Hello,
I made a small project with datagrid and tabcontrol till yesterday everthing was fine but yesterday when i was running my project it got hanged. Now when I am debugging this project its ok but when I am closing the project it gives me this error
"The Following exception has occured
NUllreference Exception: Object reference not set to an instance of an object.
okbutton.
then it closes. Kindly help me to trace this error as on debug it doesnot show and even when i created a setup file and used it no error. This error occurs only when I close only this project in vb. I tried to check each and every codes but no errors. How can i find where is this error coming from
Thanks in advance
Regards
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i have a small application in vb 6.0 that can connect to any Microsoft SQL Server db and run queries on it.But i have to hard code the Server and DB name in the code.How can i pass this information i.e server and DB name from the application.
drajkhowa
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Make a textobx in which you will enter the information?
Make a configuration file in which you will store the information?
--------------------------------------------------------
My development blog
Q:What does the derived class in C# tell to it's parent?
A:All your base are belong to us!
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strDatabase = "MyDataBase"
strServer = "MyServer"
strInstance = "Data"
strConnect = "DRIVER=SQL Server;" _
& "Trusted_Connection=Yes;" _
& "DATABASE=" & strDatabase & ";" _
& "SERVER=" & strServer & "\" & strInstance
con.ConnectionString = strConnect
con.ConnectionString = "Provider=SQLOLEDB.1;" _
& "Password=;" _
& "Persist Security Info=True;" _
& "User ID=sa;" _
& "Data Source=xyz"
Thanx & Regards.
Success is not a Destination,
... But a Journey !!
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... and I think in VB 2005.
Why does it not expand all collapsed regions when you select Toggle All Outlining. This works in C#.
Kevin
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Hello. I was successfully able to convert VB6 to VB.Net, however I get an error when calling a declare function. Part of the code looks like this:
<br />
Declare Function iRasEnumDevices Lib "rasapi32.dll" Alias "RasEnumDevicesA" (ByRef lpRasDevInfo As Integer, ByRef lpcb As Integer, ByRef lpcDevices As Integer) As Integer<br />
Declare Sub iCopyMemory Lib "kernel32" Alias "RtlMoveMemory" (ByRef hpvDest As Integer, ByRef hpvSource As RASDEVINFO, ByVal cbCopy As Integer)<br />
Declare Sub iCopyMemory Lib "kernel32" Alias "RtlMoveMemory" (ByRef hpvSource As RASDEVINFO, ByRef hpvDest As Integer, ByVal cbCopy As Integer)<br />
<br />
Public Structure RASIPADDR<br />
Dim a As Byte<br />
Dim b As Byte<br />
Dim c As Byte<br />
Dim d As Byte<br />
End Structure<br />
<br />
Dim lpRasDevInfo As New RASDEVINFO<br />
Dim lpcb As Integer = 0<br />
Dim cDevices As Integer<br />
Dim t_Buff As Integer<br />
Dim nRet As Integer<br />
Dim t_ptr As Integer<br />
Dim i As Integer<br />
<br />
lpcb = 0<br />
lpRasDevInfo.Initialize()<br />
lpRasDevInfo.dwSize = Len(lpRasDevInfo) + (Len(lpRasDevInfo) Mod 4)<br />
<br />
nRet = iRasEnumDevices(0, lpcb, cDevices)<br />
<br />
t_Buff = GlobalAlloc(GPTR, lpcb)<br />
<br />
iCopyMemory(t_Buff, lpRasDevInfo, Len(lpRasDevInfo))<br />
<br />
nRet = iRasEnumDevices(t_Buff, lpcb, lpcb)
I get an error on the line nRet = iRasEnumDevices(t_Buff, lpcb, lpcb) that says:
"Object reference not set to an instance of an object". I ran the debugger and the only thing that gets set to Nothing is the parameter I pass in ByRef. I'm not really sure what is going on, but does anyone have an idea?
Mike - I love to program!
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Mike,
I don't see your RASDEVINFO Stucture it should, at a minimum, look like this:
Public Structure RASDEVINFO
Dim dwSize As Long
<VBFixedArray(RAS_MaxDeviceType)> _
Dim szDeviceType() As Byte
<VBFixedArray(RAS_MaxDeviceName)> _
Dim szDeviceName() As Byte
End Structure
If you still have a problem with it, convert the stucture to a class structure, as you cannot pass a null value in VB.Net in a structure.
Also you need to do a lot more marshaling of most of that code.
There is an aritcle here on that, that may help you.
http://www.codeproject.com/vb/net/netcopymemorysample.asp
If you need anymore help feel free to email me and I'll see if I can help you work it out.
progload
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Hi
How do i change the colour of a control tab and the tab pages.Plz this is quite urgent.
Leavashni
-- modified at 1:56 Friday 31st March, 2006
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Dear All,
I am interested to know more about port knocking, and if it is possible through VB 6, please give me a sample code and description.
regards
Joby
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Wikipedia: Port Knocking[^]
Theres code all over the place for Sockets communication. Just Google for "vb6 sockets"...
RageInTheMachine9532
"...a pungent, ghastly, stinky piece of cheese!" -- The Roaming Gnome
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Hello 2 all!
How can i move any control, for instance a Button control on the VB Form's surface. Suppose when the form loads, its location is (0,0) and then after that i want to move this button with the mouse drage event and its position must be changed when i relese the mouse button, then what should i do?
If there is anyother option for that, you can tell me also...
Thanx in advance for helping me out
Regards,
Arfan Qadir
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chk this
http://www.vb-helper.com/howto_net_drag_drop_object.html
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You might want to re-read the original post. He's looking for a runtime moveable control, not drag and drop support for data.
RageInTheMachine9532
"...a pungent, ghastly, stinky piece of cheese!" -- The Roaming Gnome
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There's no option to make a control movable at runtime. You actually have to make your own version of the button and add support to move the control around while the mouse button is held down. There's actually quite a bit of code that goes into this. Too much to post into a forum message.
Basically, you create a new class, inheriting from Button. Add a couple of private fields to track where in the button the mouse is being held down (a Point instance works), and whether the control is being moved (Boolean).
Once that's done, the rest kind of falls into place if you think about it. Handle the button's MouseDown event to set the Moving flag to True and get the coordinates of the mouse point inside the button and save them in your private field. In the buttons MouseUp event, just set the Moving flag to False.
The MouseMove event is logically simple, but a little complicated in code. You need to calculate the new position of the control using the mouse position with respect to the buttons parent container, not the button itself. Then it's just a matter of a little math...
Public Class MovableButton
Inherits Button
Private _CursorOffset As Point
Private _Moving As Boolean
.
.
.
Private Sub MovableButton_MouseMove(blah, blah) Handles MyBase.MouseMove
If _Moving Then
Dim clientPosition As Point = MyBase.Parent.PointToClient(Cursor.Position)
MyBase.Location = New Point(clientPosition.X - _CursorOffset.X, _
clientPosition.Y - _CursorOffset.Y)
End If
End Sub
There's obviously more to this code, specially when you consider design-time requirements and any other "options" you want to put on this button, like picking which key combination to hold down to move the button.
RageInTheMachine9532
"...a pungent, ghastly, stinky piece of cheese!" -- The Roaming Gnome
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The .NET framework provides a very flexible and powerful approach to databinding that cuts down a lot of redundant code and simplifies the development process significantly. Unlike the earlier databinding models, which were limited to single data source, the .NET framework provides read/write (two ways) link to a large number of data sources such as DataSets, DataTables, Collections and also textboxes, checkboxes, radio buttons and so on.
For more read: http://www.alachisoft.com/articles/ObjectBinding.html[^]
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I have a web service which is creating a xml document.
Every thing works fine for the first time.
But the second time when i try
there is already some value in the Root element.
Declaration = objXMLDoc.CreateXmlDeclaration("1.0", Nothing, "yes")
Dim Root As XmlElement = objXMLDoc.DocumentElement
' Clear all the attributes and values from the element.
If IsNothing(Root) = False Then
Root = Nothing
root.RemoveAll
End If
(Error Line Second time)objXMLDoc.InsertBefore(Declaration, Root)
and the error i get is:-
"Cannot insert the node in the specified location"
i have tried everythng "Nothing", "removeall"
Does any one know how to solve this.
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I am having a problem with a file transfer program.
1. need to validate a network connection.
used systeminformation.network.tostring, but always comes back true.
2. need to validate file transfer was succesful.
no idea.
all help greatley appriciated.
TIA
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Are you trying to FTP a file? Which version of the framework are you using?
2.0 has My.Computer.Network.UploadFile() which you can transfer files with. It will throw an exception if the file is not transferred. I have had problems with it due to proxy servers and found it was easier to just use the free control at http://www.enterprisedt.com
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I am using file.copy(Source, Dest, overwrite)
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For your second question.
Dim value As Boolean = My.Computer.FileSystem.FileExists(file)<br />
’ Returns a Boolean indicating whether the specified file exists.
Regards,
Chatura Dilan
If at first you don't succeed, try; try again, so that you know
what not to do the next time. The answer is out there.
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HI all !
I wonder whether to load html page into rich text box or something in VB.NET ?
If someone know, pls help me. Thank you alots !
Thank !
Best Regard
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chk this link
http://www.windowsforms.com/Samples/download.aspx?PageId=1&ItemId=186&tabindex=4
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When retrieving a date field that is null, I can't set the checked property equal to false. example
if isdbnull(db field name) then
dtstartdate.checked = false
endif
For some reason this check property is set to true when retrieving that data to display on the screen....any suggestions?
Thanks,
VaLynna
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I assume this is a winform app. Put this in a button click and chk if you are able to change the checked state.
dateTimePicker1.Checked= !(dateTimePicker1.Checked)
The isDbNull might return false, chk that
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Howto:Transfer or show display Excel data worksheet into listbox with VB.NET
jikadawe
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