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Is your column bound to a table column?
These checkboxes have three states, checked(True), unchecked(False) and DBNull.Value
What is the code you have used to set up the column?
Steve
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Hi,
I'm creating an app that polls a folder (source folder) for files and moves them to another folder (destination folder). I've identified two main reasons that the move may cause an exception to be thrown.
1. The file is still being copied into the source folder by another process. Therefore the file is locked, and I need to try again later.
2. The file already exists in the destination folder.
In my catch block I need to differentiate between the two errors and handle them differently. I realise that I should perhaps be checking that the destination file does not exist before doing the move which would stop 2. happening, but it raised an interesting question for me.
What is the "proper" way do distinguish between the two errors? Obviously the IOException.message is different, but is that the way to do it?
Thanks
Ant
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The documentation doesn't say what exception you get if the file is locked. Do you get an IOException for that too?
---
b { font-weight: normal; }
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Thanks for the replies. Yes, I get the IOException for both.
I understand the concept of multiple catch blocks but in both situations I get an IOException and can only think to use the message string as the differentiator.
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Use the Err.Number as the differentiator...
Catch ex As IOException
Select Case Err.Number
Case 123
'code to handle error 123
Case 234
'code to handle error 234
End Select
Catch ex As Exception
' code to handle unexpected/unhandled errors
Steve
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Great. Thanks for your help.
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You can have multiple 'Catch' blocks within Try/End Try.
Start with specific errors and catch each err.number in a different catch block.
Your last Catch block should just catch a general 'Exception' to alert you of any unhandled errors that may occur. For example
Try
'Your implementation code
Catch ex As IOException
'Handle error here
Catch ex As Exception
'Alert unhandled error here
End Try
Steve
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Exceptions are expensive to throw, so try to avoid using them for logic decisions. The proper way to do this would be to check to see if the destination exists before you try to copy the file to it.
Dave Kreskowiak
Microsoft MVP - Visual Basic
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Dave Kreskowiak wrote: Exceptions are expensive to throw
What do you mean?
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He means its probably not the best way to deal with this. For example you know that there is a potential for an exception to be thrown (in this case a locked file) so it would be better to check for a locked file before trying to access it (thus preventing the possibility of the exception) rather than simply letting it throw an exception and dealing with it then.
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Johnathan is essentially correct. The point behind it is that Exceptions take a long time to execute compared to just checking if the file exists.
Dave Kreskowiak
Microsoft MVP - Visual Basic
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How to make validation of individual cell in a datagrid?
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What do you want to validate?
There is a certain amount of validation built into DataGrid controls.
For example, grid columns bound to number type columns in the bound table will not allow letters (A-Z) etc.
Validation is best handled at the table level when working with DataGrids.
Add a handler for the table's OnRowChanging or OnColumnChanging events, check the 'proposed value' and set an error on the row if it does not pass your validation. The grid will respond to this.
Steve
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Mr. Steve,
Thank you,can you mention a web sites where I can get some sample code on it.
With regards,
Suman
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Are you using Visual Studio?
The help explains this in detail.
Steve
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Hi,
I am trying to get the Device ID for some USB Sound Cards. I want to use the CM_Get_Device_ID function from the cfgmgr32.dll. But one of the parameters of this function is DevNode, and I have no ideea what are the DevNodes of this devices. Can you tell me how to do this? Maybe you can give me another ideea or show me a portion of code. Thank you.
-- modified at 9:09 Tuesday 8th August, 2006
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hi
i have a package developed in vb.net.how can i deploy the embeded crystal report of my project to the client machine using vb.net code?when ever i ll run my program in client machine it will ask for the login information from registry.bt from that registry value,how can i set the login information of reports that i already ve been developed in another machine having different server,password & database name
u can send me the source code at pradipta_pkc@indiatimes.com
any suggestion in this regard will be highly appreciated
thanking u all in advance
i m pradip kumar from india,working in vb.net & asp.net
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have you tried using the crystal report .SetDatabaseLogin method ?
U Xux
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thanks for the reply
will you please elaborate it with an example so that it will be easy on my part to get it.
my main concern is that my repost should be initially blank one.all the required data will be inserted into it automatically whenevr i specify the login information.
any suggestion in this regard will be highly appreciated
thanks in advance
i m pradip kumar from india,working in vb.net & asp.net
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hello,
please help me ,i want sample program to see report between two values in vb.net with mysql
Hemachandran munuswamy
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Hi,
In my vb.net editor, when I type a double number like 6.35, it automatically is converted to 6.3499999999999996 when I leave the line I am typing.
Can anyone tell me why it happens and how to avoid it?
Thanks in advance,
Vinicius
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This is because of how numbers are stored internally by the system. There's no way to avoid it. Although, I'm not seeing the problem you're describing using Single or Double types. Can we see the code this is happening in?
Dave Kreskowiak
Microsoft MVP - Visual Basic
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The code is simple:
<br />
Dim myVar as double<br />
myVar = 6.35<br />
after typing 6.35, the editor changes it to
<br />
Dim myVar as double<br />
myVar = 6.3499999999999996<br />
I understand it can be stored like that internally. What I don't understand is why in some projects it doesn't happen.
Another problem I see is that if I try to use the "Text Find" resource in my project, to find a string like 6.35 I will never locate it, so why couldn't the editor leave my numbers exactlly as they are typed?
The program I'm writing is working perfect, although these editor's changes, but it doesn't make me happy.
Vinicius
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I found out that if the number has only one dacimal value, nothing changes:
<br />
Dim myVar as double<br />
myVar = 6.3<br />
So, again, why?
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do you save the values as strings ?
just a Q.
U Xux
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