Question

I have an ASP.NET control that I have bound to a SQL result:

<asp:GridView ID="EmployeeSearchResults" runat="server" AutoGenerateColumns="False" >
  <Columns>
    <asp:TemplateField HeaderText="Status" SortExpression="Status">
      <ItemTemplate>
        <asp:Label ID="Label1" runat="server" Text='<%# (EmployeeSearchStatus(Eval("SeparationDate"),Eval("PositionTitle"),Eval("EffectiveDate"))) %>'></asp:Label>
      </ItemTemplate>
    </asp:TemplateField>                                                
  </Columns>
</asp:GridView>

My EmployeeSearchStatus function is very basic, testing the values passed in for NULL, and creating a string to display:

Public Function EmployeeSearchStatus(ByVal SeparationDate As Object, ByVal PositionTitle As Object, ByVal EffectiveDate As Object) As String
  Dim ReturnString As String = ""
    If IsDBNull(SeparationDate) Then
      ReturnString = "Currently Employed as "
    Else
      ReturnString = "Last Employed as "
    End If
    ReturnString += PositionTitle
    If IsDBNull(SeparationDate) Then
        ReturnString += " (effective " + EffectiveDate + ")."
    Else
        ReturnString += " (separated on " + SeparationDate + ")."
    End If
    Return ReturnString
End Function

Is this the proper way to handle NULL values coming back from SQL to an ASP.NET control? Is there a better technique?

Thanks,

Russell

Answer 1

Your code looks fine, although you could possibly simplify it a bit if you wanted:

Public Function EmployeeSearchStatus(ByVal SeparationDate As Object, ByVal PositionTitle As Object, ByVal EffectiveDate As Object) As String
    If IsDBNull(SeparationDate) Then
        Return "Currently Employed as " + PositionTitle + " (effective " + EffectiveDate + ")."
    Else
        Return "Last Employed as " + PositionTitle + " (separated on " + SeparationDate + ")."
    End If
End Function

The code does assume, however, that PositionTitle and EffectiveDate will never be null. If this is not enforced in the database, you could add some checks to the code to deal with these situations.