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Though doing your own record locking has it's uses, it also has some very large pitfalls. Mainly, if your not VERY careful with the lock and only keep it in place as long as is minimumly necessary, you're in for some trouble.
First, most people who do this don't know what they're doing and just throw records locks around like mad and keeping them there for minutes at a time, sometimes longer. This can kill your app's performance and the database's and it'll destroy your app's scalability. Also, what happens when your app locks records in a table, then your app crashes?? How are the locks going to get released??
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I am trying to filter fields in a table that contain percent (%) and apostrophe (') characters. I kow that to filter an apostrophe you need to add another apostrophe (''). However, when a text contains the percent (%) character in combination with an apostrophe (') character, an exception is thrown. Also, when using the % character in a filter string, it will be function as an "*" (fields starting or ending with). I need the % to be considered as a character whenever the % makes part of a string in the field. How can I address these issues?
The code below explains my question.
Dim TheTable As New DataTable
Dim col As New DataColumn("Col1")
TheTable.Columns.Add(col)
Dim TheRow As DataRow = TheTable.NewRow
TheRow("Col1") = "Filter me"
TheTable.Rows.Add(TheRow)
TheRow = TheTable.NewRow
TheRow("Col1") = "Filter me%"
TheTable.Rows.Add(TheRow)
TheRow = TheTable.NewRow
TheRow("Col1") = "Filter me'"
TheTable.Rows.Add(TheRow)
TheRow = TheTable.NewRow
TheRow("Col1") = "Filter me%'"
TheTable.Rows.Add(TheRow)
TheRow = TheTable.NewRow
Dim filteredrows() As DataRow
filteredrows = TheTable.Select("Col1 Like 'Filter me'")
MsgBox(filteredrows.Length)
'THE NEXT LINE WILL RETURN ALL RECORDS. I NEED ONLY THE RECORD ENDING WITH (OR CONTAINING) THE CHARACTER %
filteredrows = TheTable.Select("Col1 Like 'Filter me%'")
MsgBox(filteredrows.Length)
'THE NEXT LINE WILL RETURN TWO RECORDS (Filter me) and (Filter me'). I need it to return (Filter me') only
filteredrows = TheTable.Select("Col1 Like 'Filter me'''")
MsgBox(filteredrows.Length)
'THE NEXT LINE WILL THROW AND ERROR: "Error in Like operator: the string pattern 'Filter me%'' is invalid"
filteredrows = TheTable.Select("Col1 Like 'Filter me%'''")
MsgBox(filteredrows.Length)
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To escape the %, so you are searching for a %, you will likely need to put brackets around the %. Placing a backslash before the % may also work, but I always go with the brackets. For example:
filteredrows = TheTable.Select("Col1 Like 'Filter me[%]'")
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mbv800 wrote: 'THE NEXT LINE WILL RETURN ALL RECORDS. I NEED ONLY THE RECORD ENDING WITH (OR CONTAINING) THE CHARACTER %
filteredrows = TheTable.Select("Col1 Like 'Filter me%'")
You can use a character set for the % character:
Col1 Like 'Filter me[%]'
You can also use an escape character:
Col1 Like 'Filter me!%' escape '!'
Despite everything, the person most likely to be fooling you next is yourself.
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Some languages like C++ and Java have mode for the graphics object called XORmode.
This makes the rubber banding easier. You just set the XORmode for the graphics object and it does the work.
In VB 2008, yes, it could be done but it looks like it is several times more effort.
I hope I am missing something.
Please help.
Thanks,
Stefan
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Microsoft has a How-to in this very issue-
http://support.microsoft.com/kb/71488[^]
Take a look. Good luck!
Ranjit Viswakumar
Professional Services Specialist
http://hostmysite.com/?utm_source=bb
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That's not for VB 9, that's for VB 3!
Despite everything, the person most likely to be fooling you next is yourself.
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Hi all...
I am creating a small web-browser.I have almost completed my program.The remaining part is that when someone click on "bookmark" menustrip,it will store the url to a file (called as something.dat) and dynamically create a new menustrip of that url below "bookmark" menustrip (as same done with Internet Explorer "Add to Favourite" feature). Now anyone can access that url by clicking its menustrip item.
Please suggest me how can I do this.
Thanks.
Gagan
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You add menuitems the same way you add controls to a form. You create an instance of the ToolStripMenuItem, set it's properties, wire up it's events, then add it to the Items collection of the parent you want it to show up under.
Dim newMenuItem As New ToolStripMenuItem
newMenuItem.Size = New Size(152, 22)
newMenuItem.Text = "Some &Menu Item"
AddHandler newMenuItem.Click, AddressOf MyMenuItemHandler
FileToolStripMenuItem.Items.Add( newMenuItem )
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I have a need to write code similar to the following:
Private Sub Block()
Call Sub A(sender, e)
Call Sub B(sender, e)
Call Sub C(sender, e)
End Sub
where Subs A, B, & C have differing arguments.
Is this possible? If not, is there any way to do this?
I can supply specific code if necessary, but it can get
rather lengthy...
I appreciate any help.
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Hi,
pass the arguments to the containing sub, something along these lines (details may be wrong,
normally I don't write VB):
Private Sub Block(arg1 as type1, arg2 as type2)
Call Sub A(arg1, arg2)
Call Sub B(arg1, arg2)
Call Sub C(arg1, arg2)
End Sub
Luc Pattyn [Forum Guidelines] [My Articles]
- before you ask a question here, search CodeProject, then Google
- the quality and detail of your question reflects on the effectiveness of the help you are likely to get
- use the code block button (PRE tags) to preserve formatting when showing multi-line code snippets
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Working with Active Directory in VB.NET
By Psycho-*Coder*-Extreme
Read atricle at:
href="http://www.codeproject.com/KB/system/active_directory_in_vbnet.aspx#_comments">http://www.codeproject.com/KB/system/active_directory_in_vbnet.aspx#_comments
Would like to know how this could be modified if possible to allow endusers to reset their own password when it has expired.
Allow for a questions/answer and maybe the last 4 of SSN. but allowing the user to reset password without providing to much security access to do so.
Is there already a VB.net ap or code that can do this?
Thanks
sd
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Here's a dumb observation. If the password has expired, they either won't be able to login, or they'll be forced to change the password upon login, without using any of your code.
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I am calling a subroutine that starts with the following line:
Private Sub AddPayrollTable(ByVal TableCode As Integer, ByRef PayrollArray As String)
When this subroutine gets called I get an error that says "Object reference not set to an instance of an object."
This has lead me to believe that the array (PayrollArray) has not been initialized so I ask, how can I initialize an array that is a parameter in a subroutine?
Side note: When I reference the array directly in the AddPayrollTable subroutine instead of passing it as a parameter, I get no error.
Thanks,
Craig
"That rug really tied the room together."
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craigmg78 wrote: Private Sub AddPayrollTable(ByVal TableCode As Integer, ByRef PayrollArray As String)
Well, I see a couple of problems. The first parameter is passed as an Integer with the name "*Code". This leads me to believe it should be an enum, but I'm saying this based on very limited information. Right now, you're passing a "magic number" that offers no documention about what it means.
The second parameter is not being passed an array, but as a single String. Initializing an array is really mean to be done by the caller, not the callee. But, again, you haven't provided any information as to what this method does with the array and what the contents of the array is supposed to be, so it's difficult to say what the correct solution is.
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Hi,
assuming your code compiles fine and produces a run-time error "Object reference not set ..."
when it somewhere calls your sub AddPayrollTable(...) that really means the caller hasn't
allocated the object (string?) that is being passed as the second parameter.
Yes, it is the caller that needs to initialize the parameters it is passing to the callee;
the callee can only accept them any way they come.
BTW: the name implies it would be an array, but then it should say As String()
Luc Pattyn [Forum Guidelines] [My Articles]
- before you ask a question here, search CodeProject, then Google
- the quality and detail of your question reflects on the effectiveness of the help you are likely to get
- use the code block button (PRE tags) to preserve formatting when showing multi-line code snippets
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Yes, I see now what the problem was thanks to Dave and Luc. I was calling the sub and passing an array to a string slot. Luc is correct, it should have said String(). Whoops. Thank you!
"That rug really tied the room together."
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Unless you want to replace the entire array with another array, you should not send the parameter by reference. You can still change the items in the array when sending the parameter by value:
Private Sub AddPayrollTable(ByVal TableCode As Integer, ByVal PayrollArray As String())
However, you still have to create the array before calling the method.
If you want to create the array in the method, you should return the array from it:
Private Function GetPayrollTable(ByVal TableCode As Integer) As String()
If you want to add items to the collecion, it should be a list instead of an array:
Private Sub AddPayrollTable(ByVal TableCode As Integer, ByVal PayrollList As List(Of String))
Despite everything, the person most likely to be fooling you next is yourself.
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Hello Everyone.
How is possible send a report with out the preview?
Is VB6 is possible but here? I dont know..
Any idea?
Just is case.. is was my source in VB6... BR
Dim strReportName As String
Dim intReportDestination As Integer
strReportName = "test.RPT"
With cr
.ReportFileName = "label.rpt"
.DataFiles(0) = "batabase.mdb"
.Destination = crptToPrinter
.PrinterName = Zebra
.Action = 1
End With
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How check for framework version
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You can write some bad code and browse to that page. The bottom of the error message will state the version of .NET that's in use.
For example[^]
Good luck.
Ranjit Viswakumar
Professional Services Specialist
http://hostmysite.com/?utm_source=bb
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I'm assuming he's talking about find out which version the app is running under in his own code, not by crapping out an app and looking at the wreckage.
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