Click to See Complete Forum and Search --> : handling DBNULL


Bill Crawley
May 23rd, 2008, 02:43 AM
Hi All,

I have a column on an SQL Server DB that is declared as type integer and is nullable.

I have a query that includes this column that is bound to a typed dataset.

This is the Typed Dataset's Property

<Global.System.Diagnostics.DebuggerNonUserCodeAttribute()> _
Public Property RateableValue() As Integer
Get
Try
Return CType(Me(Me.tableCustomerSystemFieldsAssetLocation.RateableValueColumn), Integer)
Catch e As Global.System.InvalidCastException
Throw New Global.System.Data.StrongTypingException("The value for column 'RateableValue' in table 'CustomerSystemFieldsAssetLocation'" & _
" is DBNull.", e)
End Try
End Get
Set(ByVal value As Integer)
Me(Me.tableCustomerSystemFieldsAssetLocation.RateableValueColumn) = value
End Set
End Property

How do I test for a null value against this or should I change the code above. As soon as It hits the row:

Return CType(Me(Me.tableCustomerSystemFieldsAssetLocation.RateableValueColumn), Integer)

My app crashes with conversion error DBnull to integer.

HairyMonkeyMan
May 23rd, 2008, 03:02 AM
Is tableCustomerSystemFieldsAssetLocation a row from the datatable? If so, check whether Me.tableCustomerSystemFieldsAssetLocation.IsNull("RateableValueColumn") is true before getting the value.