Cast from string "VelvetBoo" to type 'Double' is not valid

[cmaras]

Visual Basic .NET

 

Ok, I have been reading about these conversion problems on this forum and if I get it right, why it would like to convert a String into a Double wóuld be if you are doing some kind or mathematical operation with that value like:

 

Dim strvalue = "VelevetBoo"

strValue = strValue / 2

 

this would force .NET to try converting the String to a Double or Integer to try to solve the problem, this is where it will throw the exception because it can't convert characters to numbers. Just trying to find out where I am wrong in my thinking, just giving you an idea where I'm coming from.

 

Ok my problem comes from a Method where I feed it data through parameters it looks like this.

 

Public Sub UpdateDataAdapter(ByVal Exp_Date As String, ByVal Rec_Type As String, _

ByVal IPStart_Rng As String, ByVal IPEnd_Rng As String, ByVal Room As String, _

ByVal Detail As String, ByVal Nickname As String)

 

I use the following code to fill the parameters:

 

UpdateDataAdapter(txtExp_Date.Text, txtRec_Type.Text, + _

strStartIP, strEndIP, cmbRoom.Text, txtDetail.Text, + _

txtNickname.Text)

 

All these parameters are of the String data type, either TextBox's or Variables defined As String.

 

My problem is that the Textbox txtNickname results in the error:

Cast from string "VelvetBoo" to type 'Double' is not valid

 

I can't see the problem, I'm not doing any kind of mathematical operation on this value so why does it want to convert it to Double?

 

All I want is it to read it into the UpdateDataAdapter method and to use the data to populate an update statement which looks like this.

 

objDBconn.Open()

 

objDataAdapter.UpdateCommand = New OleDb.OleDbCommand()

objDataAdapter.UpdateCommand.CommandText = "UPDATE " + strTable + " SET " + _

"[Exp_Date] = " + Exp_Date + ", [Rec_Type] = " + Rec_Type + ", [iPStart_Rng] = " + IPStart_Rng + ", " + _

"[iPEnd_Rng] = " + IPEnd_Rng + ", [Room] = " + Room + ", [Detail] = " + Detail + ", " + _

"[Nickname] = " + Nickname + _

"Where [iD] = " + strCurrentID

 

objDataAdapter.UpdateCommand.Connection = objDBconn

 

objDataAdapter.UpdateCommand.ExecuteNonQuery()

 

objDBconn.Close()

End Sub

 

I realize that this might not be the optimal way to use SQL in code but I'm a beginner so if you have any pointers please do tell. Personally I find it a bit cumbersom to write SQL querys in code, so if there is a better way I'm all ears.

 

But either way I would like to know why .NET is doing this conversion.

 

Thank you for listening and I appriciate your help.

 

Claudio

[PlausiblyDamp]

If you are concatenating strings use & instead of + as + is a mathematical operator that can double as a string operator - this could be causing the problem.

 

A better way would be to use server side stored procedures - search these forums and MSDN for a lot more information on Stored Procedures.

[cmaras]

Thanks for your post, I haven't changed the + to & yet but sounds like a good idea.

 

Regarding the Server-side Stored Procedures it's an Access Database so I don't know if you have the option of stored procedures.

 

But thanks for your suggestion.

 

Claudio

[cmaras]

Well it's been proven I'm a moron, well as anybody who probably looked at this code saw.

 

Again thanx for the pointer "PlausiblyDamp" you pointed me in the right direction.

 

The problem was that I was binding controls and variables together which doesn't require + or &. So I removed the + from the UpdateDataAdapter() and everything was back to normal.

 

Again tahnx again for you extreamly fast reply "PlausiblyDamp".

 

Claudio

[PlausiblyDamp]

Not sure if Access does suppor them or not either. You may want to investigate MSDE from Microsoft which gives you a SQL server compliant engine - works well with access as a front end.

[cmaras]

Correction I'm NOT binding the control or variables together, what I wanted to say was I wasn't binding control or variables with text.

 

I hope taht makes sense.

 

Claudio

[Nerseus]

Yes, from what I've read on other threads, Access does support stored procedures but you have to create and edit them by hand. Meaning, you'd have to run a command like "CREATE PROCEDURE test1..." for Access to create it. AFAIK, there is no GUI front end to do this with Access itself.

 

-Nerseus

[cmaras]

Thanks for the info "Nerseus"..

 

Claudio