Execute Scalar to trap error in case of no records returned

Question

I have got this code below:

Dim lJobName As String = \"\"
SQLCommand.CommandText = \"Select JobName from Jobs where Id = @Id \"
SQLCommand.Parameters.Add(New         


        

Answer 1

ExecuteScalar() returns Nothing if there is an empty result set, which should be preserved when assigning into a string, so I would try this:

Dim lJobName as String = String.Empty
lJobName = SqlCommand.ExecuteScalar()
If lJobName Is Nothing Then
    'Do something with the error condition
Else
    'Do something with lJobName which contains a valid result.
End If

Of course this doesn't help you if you cause a SqlException, but it should handle the problem of no rows found in the result set.

http://msdn.microsoft.com/en-us/library/system.data.sqlclient.sqlcommand.executescalar.aspx