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Hi Everyone,
Here is an interesting problem. I am trying to add an expression column to a dataset that already contains data. The expression involves coverting the string data in a specific column into numeric data.
The MS help system says I should use the following example to perform this operation: myDataColumn.Expression="Convert(total, 'System.Int32')"
In having incorporated this into my code, I get the following error:
"Input string was not in a correct format."
Here is the actual code:
Dim tmpCol As New DataColumn<br />
tmpCol.DataType = System.Type.GetType("System.Single")<br />
tmpCol.AllowDBNull = False<br />
tmpCol.Caption = "nResult"<br />
tmpCol.ColumnName = "nResult"<br />
tmpCol.DefaultValue = 0.0<br />
tmpCol.Expression = "Convert(Item01, 'System.Single')"<br />
<br />
tmpDS.Tables(0).Columns.Add(tmpCol)
I have tried several different ways of using the Convert function, but nothing I've tried works.
Has anyone else had experiences with using the Convert function that might help???
Thanks,
cb
Additional Info:
1. The column, Item01, in the tmpDS dataset is a varchar field that contains only numeric data.
2. The tmpDS dataset is obtained from an XML data file.
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Curtbroo wrote: , but nothing I've tried works.
Perhaps if you told us what happens when it 'doesn't work' ???
Christian Graus
Driven to the arms of OSX by Vista.
Read my blog to find out how I've worked around bugs in Microsoft tools and frameworks.
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Sorry,
Perhaps if I had put this in bold earlier...
In having incorporated this into my code, I get the following error:
"Input string was not in a correct format."
cb
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OK, so the two possibilities are that your filter is wrong, or your input includes values that will not convert to a single. Have you checked the input ?
Christian Graus
Driven to the arms of OSX by Vista.
Read my blog to find out how I've worked around bugs in Microsoft tools and frameworks.
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Yes. I've checked the xml file and all of the values in question are either numeric or null.
I've tried using the 'System.Int32' conversion definition as well and received the same error; thinking that perhaps the 'System.Single' might be incorrect.
I'm wondering if there isn't some issue with adding the new column to an existing dataset already containing data.
cb
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I'm having consistent crashes when accessing the solution property screens (application, compile, debug, etc tabs).
So if I open solution, and I double click My Project (which opens up the config screen), VS just immediately dumps out. If I reboot, the solution(s) start acting normal again. Just annoying.
Has anyone else run into this? Any idea what causes it? Once the crashing starts when double clicking "My Project", a reboot has to be done to prevent the crashing. At times, that can be a pain in the ......
"There's no such thing as a stupid question, only stupid people." - Mr. Garrison
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I've had that happen once or twice. I solved it by navigating to the project folder in Explorer, enabling the "Show hidden files", finding and deleteing the myProject.suo file. Launch Visual Studio and open your project.
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That did it. Thanks Dave!
"There's no such thing as a stupid question, only stupid people." - Mr. Garrison
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Does anyone know how to install an application that you created on another computer using a disk or any other method? I clicked publish, distribute on a CD rom, then when i try to install it on some computers there is a message that pops up saying
"Unable to install or run the application. The application requires that assembly System.Core Version 3.5.0.0 be installed in the Global Assembly Cache (GAC)"
Does anyone know what that means? It only happens on some computers, some are able to install the software. Is there anyway to install the program without needing that GAC thing?
Thanks
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Hi,
System.Core 3.5.0.0 is part of .NET 3.5 which seems to be a prerequisite of your app.
There are two ways to go now:
- maybe you don't really need .NET features beyond .NET 2.0 and could rebuild your app for .NET 2.0, giving it a much bigger probability of running on modern PCs (you can choose the target .NET version in your project settings);
- or you keep the app as is, and make sure .NET 3.5 is installed; creating an installer would allow you to check for that automatically.
Luc Pattyn
I only read code that is properly indented, and rendered in a non-proportional font; hint: use PRE tags in forum messages
Local announcement (Antwerp region): Lange Wapper? 59.24% waren verstandig genoeg om NEEN te stemmen; bye bye viaduct.
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Thank you very much i think that helps.
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Hi Everyone,
I have created one button in VB .net which on click creates a backup/copy of my sql database file, i.e. client.mdf file, into a separate folder. The code is like this:
Private Sub Button_Click()
Dim dbdlg As New FolderBrowserDialog()
con.Close()
CurrentDatabasePath = "F:\..\client.mdf"
If dbdlg.ShowDialog() = Windows.Forms.DialogResult.OK Then
Dim pathtobackup As String
pathtobackup = dbdlg.SelectedPath.ToString()
File.Copy(CurrentDatabasePath, pathtobackup, True)
End If
End Sub
The error I am getting while executing File.Copy statement.It shows :
The process cannot access the file 'F:\...\client.mdf' because it is being used by another process.
Can someone tell me how to resolve this error? I think I have to detach the database, if yes, how?
Thanks
R.S
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You can't make a copy of the .mdf file while SQL server is running. Instead of trying to copy live database file, why not try running a TSQL query to backup the database to a separate file and then copying or moving that?
The SQL required looks something like this:
BACKUP DATABASE MyDatabase TO DISK = 'C:\Temp\MyDatabase.BAK' WITH INIT;
Now you can just write some VB code to shift the newly created .bak file.
Hope that helps!
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Hi,
Can you pls elaborate how to do this?
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jeshra279 wrote: Can you pls elaborate how to do this?
1) Run the TSQL backup query on the database that you want to back up
2) MSSQL will create the backup (.bak file) in the location you specified in the query
3) Run your VB.net routine to copy or move the .bak file to the location of your choice
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Hi
I have a function that returns the connection to DBASE server.
I use this function to connect to the server.
When I use for testing with the .mdb database, the connection is set and application worksd fine.
When I use the server address in Data Source to connect, the application is exited.
I dont understand why this happens.
Any help on this will be very much helpful.
Thanks in Advance.
modified 28-Nov-12 7:53am.
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Are you getting an error message? If so, it would be helpful if you could include it.
So you're saying that is works when you use the bottom connection string, but not when you use the top one? The top one doesn't have the .mdb extention, is it supposed to? Does the user have access to that network path? Is that database protected by a username/password that you forgot to include?
Hope these suggestions will help you find your answer.
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Yes, works fine for .mdb file.
There should'nt be a extension for DBASE database.
User has access to that path.
there is no username/password for that drive.
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How about an error message? Perhaps if you debug the program you can get a more detailed error message?
My only other thought is to use the User ID and Password portions of the connection string, even if your database doesn't have one?
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There's no error msg produced. I tried debugging, but no use.
Have also used User ID and Password portions, but no progress.
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Well, then perhaps it's not the connection string that is causing the problem. How about posting more of your code, like where the connection string gets used or looking through some of the first bits of code that get run when your program launches.
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I have not used DBase for years, have you checked out connectionstrings.com for the right syntax.
DBase IV came in a number of flavours and not all drivers (Jet) work with all flavours. I know I'm using a foxpro driver to get at some of our files so you may be running into a compatibility problem. Sorry I have no idea how to get around it other than testing each driver till one works.
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I know that the below line will delete the file,but it puts it in Recycle Bin.
I want to delete the file completely from the PC.
File.Delete("C:\l\A.txt")
Any suggestion will be helpful.
Thanks in Advance.
modified on Monday, October 19, 2009 9:01 AM
modified 28-Nov-12 7:54am.
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vijay2482 wrote: but it puts it in Recycle Bin
Not on my end
system.io.file.delete()
permently deletes the file
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