Solved

Getting a "Conversion from type 'DBNull' to type 'String' is not valid" error.

Posted on 2014-10-07
6
159 Views
Last Modified: 2014-10-13
Isn't this the correct way to check for NULLS if the value is coming from a Database? I'm getting the  "Conversion from type 'DBNull' to type 'String' is not valid" error on the indicated line. The variable clsDE.capacity is defined as a "String".

    Public Function GetDetailsEquipmentRecord(ByVal iEquipment_ID As Integer, ByVal clsDE As CalTableClasses.CalibrationClasses.DETAILS_Equipment, ByVal EH As ErrorHandling.ErrorHandler)
        Try
            DL.GetDetailsEquipmentRecord(iEquipment_ID, EH)

            If EH.Success Then
                If EH.DataSet.Tables(0).Rows.Count = 1 Then
                    Dim row2 As DataRow = EH.DataSet.Tables(0).Rows(0)
                    clsDE.capacity = If(DBNull.Value.ToString.Equals(row2("Capacity")), "", row2("Capacity"))  '----------> Throwing exception
                End If
            End If

        Catch ex As Exception
            EH.ErrorMessage = "CalBusiness/GetDetailsEquipmentRecord() - " & ex.Message & "~E"
        End Try

        Return EH
    End Function

Open in new window

0
Comment
Question by:BlakeMcKenna
[X]
Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people just like you are talking about what matters.

  • Help others & share knowledge
  • Earn cash & points
  • Learn & ask questions
  • 3
  • 2
6 Comments
 
LVL 29

Accepted Solution

by:
Paul Jackson earned 500 total points
ID: 40367335
try :

clsDE.capacity = If(IsDBNull(row2("Capacity")), "", row2("Capacity"))
0
 

Author Comment

by:BlakeMcKenna
ID: 40368243
I actually went a different route that I've always used in the past. It's more primitive but works like a charm.

clsDE.capacity = "" & row2("Capacity")

Open in new window

0
 

Author Comment

by:BlakeMcKenna
ID: 40368995
Paul,

I did try your suggestion and it worked but not in all instances.
0
 

Author Comment

by:BlakeMcKenna
ID: 40369680
I've requested that this question be deleted for the following reason:

I figured it out...
0
 
LVL 29

Expert Comment

by:Paul Jackson
ID: 40369681
Shouldn't be deleted, QA's answer or both QA's and Expert's answer should be selected as the solution and added to the knowledgebase.
0

Featured Post

On Demand Webinar: Networking for the Cloud Era

Ready to improve network connectivity? Watch this webinar to learn how SD-WANs and a one-click instant connect tool can boost provisions, deployment, and management of your cloud connection.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

If you're writing a .NET application to connect to an Access .mdb database and use pre-existing queries that require parameters, you've come to the right place! Let's say the pre-existing query(qryCust) in Access takes a Date as a parameter and l…
1.0 - Introduction Converting Visual Basic 6.0 (VB6) to Visual Basic 2008+ (VB.NET). If ever there was a subject full of murkiness and bad decisions, it is this one!   The first problem seems to be that people considering this task of converting…
There are cases when e.g. an IT administrator wants to have full access and view into selected mailboxes on Exchange server, directly from his own email account in Outlook or Outlook Web Access. This proves useful when for example administrator want…
Monitoring a network: why having a policy is the best policy? Michael Kulchisky, MCSE, MCSA, MCP, VTSP, VSP, CCSP outlines the enormous benefits of having a policy-based approach when monitoring medium and large networks. Software utilized in this v…

724 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question