Dim sqlStr As String = "SELECT * FROM urlTable WHERE urlName='" & CStr(comboSearch.SelectedItem) & "'"
Dim dataAdapter As New OleDb.OleDbDataAdapter(sqlStr, connStr)
dataAdapter.Fill(dt)
dataAdapter.Dispose()
I have declared all the neccessary variblas and the code is working fine
Now lets say i give this command...
urlStart = CStr(dt.Rows(0)("urlStart"))
Now the code will work fine when there is a value in urlStart...but will generate an error when it is NULL...
what is the command where i can find whether urlStart has a NULL value and if not only run the above command?
Im looking for a valid code something like
If dt.Rows(0)("urlStart") <> NULL Then
urlStart = CStr(dt.Rows(0)("urlStart"))
Else
urlStart = ""
End if
What i want is how to find whether it is NULL or not without first??
I get this warning too...
Warning1 :Variable 'urlStart' is used before it has been assigned a value. A null reference exception could result at runtime.
Thanx a lot :D - Edited byRanhiru123 Tuesday, June 24, 2008 1:40 PMAdded information
- Changed TypeRanhiru123 Tuesday, June 24, 2008 1:38 PMMy fault :D
- Edited byRanhiru123 Tuesday, June 24, 2008 1:41 PMAdded information
-
| | Ranhiru123 Tuesday, June 24, 2008 1:36 PM | Research DBNull. This is a sample from VB Help. But in general, you may be going into the wrong direction with your implimentation.
If you can create a typed dataset, do so.
Add a select qry to the data adapter.Then you can access like so:
MyDataAdapter.GetByCustomerId("C123456")
Otherwise, This gets ugly
"CStr(dt.Rows(0)("urlStart"))"
on the other hand you can reference like so:
MyCurrentRow.urlstart = "somevalue"
| PrivateSubOUtputLabels(dtAsDataTable) |
| DimlabelAsString |
|
| 'Iteraterowsoftable |
| ForEachrowAsDataRowIndt.Rows |
| DimlabelLenAsInteger |
| label=String.Empty |
| label+=AddFieldValue(label,row,"Title") |
| label+=AddFieldValue(label,row,"FirstName") |
| label+=AddFieldValue(label,row,"MiddleInitial") |
| label+=AddFieldValue(label,row,"LastName") |
| label+=AddFieldValue(label,row,"Suffix") |
| label+=vbCrLf |
| label+=AddFieldValue(label,row,"Address1") |
| label+=AddFieldValue(label,row,"AptNo") |
| label+=vbCrLf |
| labelLen=Len(label) |
| label+=AddFieldValue(label,row,"Address2") |
| IfLen(label)<>labelLenThenlabel+=vbCrLf |
| label+=AddFieldValue(label,row,"City") |
| label+=AddFieldValue(label,row,"State") |
| label+=AddFieldValue(label,row,"Zip") |
| Console.WriteLine(label) |
| Console.WriteLine() |
| Next |
| EndSub |
|
| PrivateFunctionAddFieldValue(labelAsString,rowAsDataRow,_ |
| fieldNameAsString)AsString |
| IfNotDbNull.Value.Equals(row.Item(fieldName))Then |
| ReturnCStr(row.Item(fieldName))&"" |
| Else |
| ReturnNothing |
| EndIf |
| EndFunction | | | DaveKlem Wednesday, July 02, 2008 7:23 AM | This question has nothing to do with either GAX or GAT, please post it to a more appropiate forum.
thanks,
-vga.
Working with GAX/GAT/DSL? Download SFT now! http://softwarefactoriestoolkit.net- Proposed As Answer byvga Thursday, July 03, 2008 2:08 AM
-
| | vga Thursday, July 03, 2008 2:08 AM |
|
index > Visual Studio Guidance Automation Toolkit > How to find a NULL in a dataset ?