String to Double not Valid?

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Hi,
As part of my on-going testing of Excel Automation using vb 2008 and Office 2007, I decided to create a virtual Machine in my Local computer.

I'm still trying to find solution bout the InterOp assembly which I posted in another thread.

In my Query Form, I declared the Textbox value as string, then converted to double and is use in my Select Statement,

Dim Rate1 as String = Me.Textbox6.Text
Dim nRate as Double = CDbl(Rate1)

Tested this in my local and is working Okay. Created a SetUp and copied the Setup to my Virtual Machine and Install It, the program is working okay and i can produce views(DGV) and outputs(textfile). Some reports uses the TextBox6 and its value, but this is where I recieve this Error "Convert String to double is Invalid?",

in Prerequisite Components, i checked this;

Windows Installer 3.1<br />
.Net Framework 3.5 SP1<br />
Microsoft Office 2007 Primary InterOp Assemblies

I have also installed windows xp and office 2007 in my virtual machine.

Posted 31-Jan-12 20:39pm

Alan Tuscano

Updated 31-Jan-12 20:50pm

Rajesh Anuhya

v4

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Rajesh Anuhya 1-Feb-12 2:51am

Edited.
--RA

Alan Tuscano 1-Feb-12 2:54am

Hi Rajesh, why can't i do that stuff.. i tried making it into vb code, tried making it into bold but nothing has change. And U simply updated it by making some lines into red and highlighting some... cool.. :)

3 solutions

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Sander Rossel · Accepted Answer · 2012-01-31T20:49:00

Solution 1

Well, not all Strings are compatible Doubles. How would, for example, "Hi" or an empty String be converted to a numeric value?
Of course I can't see your dataset, but it seems there are some non-numeric values in there.
What would be a lot safer is to call Double.TryParse[^].
Usage as follows:

VB

Dim d As Double ' If only this were C#, we would've had Double d :)
If Double.TryParse(Me.TextBox6.Text, d) Then
   ' The string was successfully converted.
   ' Your variable d now has the converted value.
Else
   ' The string was not a numeric value.
   ' Nothing happened to d.
End If

Posted 31-Jan-12 20:49pm

Sander Rossel

Updated 31-Jan-12 20:50pm

v2

Comments

Sergey Alexandrovich Kryukov 1-Feb-12 2:57am

Of course. My 5.
Not clear what all the OP's text to do with this question. It isn't a question though; I would not answer.
--SA

Sander Rossel 1-Feb-12 6:57am

Thanks SA. The OP clearly had a converting problem. There was only one line of code where the conversion could fail, so I merely suggested this approach :)
Though I agree the problem wasn't very clear to begin with.

Alan Tuscano 1-Feb-12 2:57am

Hi Naerling,
forgot to detail textbox6.. :)
It will only be used when User selects the report that will create Excel spreedsheet, and the value from the textbox is the Exchange rate.

I'll try your code and get back to you soon.

Simon_Whale 1-Feb-12 4:16am

+5 good answer and also like your commented reference too

Sander Rossel 1-Feb-12 6:57am

Thanks :)

Alan Tuscano 1-Feb-12 19:48pm

Naerling. Got your code working. Tnx.. I also got my program to run on other computer.. many tnx too all that shared in helping me. Tnx.. :)

Sander Rossel 2-Feb-12 2:12am

No problem! Don't forget to accept the answer that helped you :)

CRDave1988 · Accepted Answer · 2012-01-31T20:58:00

Solution 2

use

VB

Dim nRate as Double=Double.Parse(Rate1 );

Posted 31-Jan-12 20:58pm

CRDave1988

Dave Kreskowiak · Accepted Answer · 2012-02-01T02:10:00

Solution 3

You have to do some validation of the textbox text before you convert it.

If TextBox6 is blank, CDbl will throw the error you're seeing.

If would be better to use Double.Parse() or .TryParse() instead, but you still have to make sure the textbox has a value before you try and parse it.

Posted 1-Feb-12 2:10am

Dave Kreskowiak