How to resolve the error Conversion from type 'DBNull' to type 'Date' is not valid.

Question

0.00/5 (No votes)

See more:

VB

Dim InveststrBuilder1 As New StringBuilder
 If Trim(RSmartUtl.DtFormat) = "DD-MM-YYYY" Then
                                    InveststrBuilder1.Append("document.forms[0].INVEST_POLICY_DATE_DD.value=unescape('" & Format(DatePart(DateInterval.Day, objDR("DOC_DATE")), "00") & "');" & vbCrLf)
                                    InveststrBuilder1.Append("document.forms[0].INVEST_POLICY_DATE_MM.value=unescape('" & Format(DatePart(DateInterval.Month, objDR("DOC_DATE")), "00") & "');" & vbCrLf)
                                End If
                                If Trim(RSmartUtl.DtFormat) = "MM-DD-YYYY" Then
                                    InveststrBuilder1.Append("document.forms[0].INVEST_POLICY_DATE_DD.value=unescape('" & Format(DatePart(DateInterval.Month, objDR("DOC_DATE")), "00") & "');" & vbCrLf)
                                    InveststrBuilder1.Append("document.forms[0].INVEST_POLICY_DATE_MM.value=unescape('" & Format(DatePart(DateInterval.Day, objDR("DOC_DATE")), "00") & "');" & vbCrLf)
                                End If
                                InveststrBuilder1.Append("document.forms[0].INVEST_POLICY_DATE_YY.value=unescape('" & Format(DatePart(DateInterval.Year, objDR("DOC_DATE")), "0000") & "');" & vbCrLf)

When Date is null in database i.e back end I get the error
Conversion from type 'DBNull' to type 'Date' is not valid.

Posted 8-Apr-14 20:07pm

Member 9410081

Updated 8-Apr-14 20:10pm

Maciej Los

v2

Add a Solution

2 solutions

Solution 1

Check for DBNull.Value[^] before you start processing with date...

Posted 8-Apr-14 20:12pm

Maciej Los

Comments

Member 9410081 9-Apr-14 2:23am

No still didn't get proper solution.

Maciej Los 9-Apr-14 2:34am

:laugh:
Have you wrote any if... then... else... end if statement?

Add a Solution

Add your solution here

Treat my content as plain text, not as HTML

Preview 0

…

Existing Members

Sign in to your account

...or Join us

Download, Vote, Comment, Publish.

Your Email
Password
Forgot your password?

Your Email
This email is in use. Do you need your password?
Optional Password

I have read and agree to the Terms of Service and Privacy Policy
Please subscribe me to the CodeProject newsletters

When answering a question please:

Read the question carefully.
Understand that English isn't everyone's first language so be lenient of bad spelling and grammar.
If a question is poorly phrased then either ask for clarification, ignore it, or edit the question and fix the problem. Insults are not welcome.
Don't tell someone to read the manual. Chances are they have and don't get it. Provide an answer or move on to the next question.

Let's work to help developers, not make them feel stupid.

This content, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)

Bernhard Hiller · Accepted Answer · 2014-04-08T21:32:00

Solution 2

objDR("DOC_DATE") contains data retrieved from a database, doesn't it? And there in the database, the corresponding column may contain NULL, which gets translated into DBNull when you retireve the data into your .Net program.
The DatePart function then tries to cast that into a DateTime variable and fails: DateTime is a value type and must not be null.
Hence check for objDR("DOC_DATE") being DBNull.Value before you do that processing, as Macej told you:

VB

If objDR("DOC_DATE") = DBNull.Value Then
    MessageBox.Show("No date given!")
Else
    'your code from above
EndIf

Posted 8-Apr-14 21:32pm

Bernhard Hiller

v2

Comments

Member 9410081 9-Apr-14 3:52am

Thanks

Maciej Los 9-Apr-14 4:17am

Does it exactly what i was trying to tell you?
Please, accept my answer as a solution (green button) and vote-up both answers. This is the way how we say "Thank you" ;)

Maciej Los 9-Apr-14 4:17am

+5

Bernhard Hiller 9-Apr-14 4:21am

Thanks. Looks like the guy needed some more background information, and perhaps also some spoon-feeding...

Maciej Los 9-Apr-14 5:36am

Yes. He needs to back to basics!