Handling Null Parameter

  • The following expression :

    =IIf(Not IsNothing(Parameters!Rejected.Value), Parameters!Rejected.Value.ToString(), "Null")

    gives the following error when the parameter is null:

    "Object reference not set to an instance of an object."

    So I am only trying to display the value of the parameter when it is not null but it still won't work. Can someone point me to the solution please.

    Thanks,

  • I don't now what's wrong with the expression, but I get the same error. You can work around it by replacing [font="Times New Roman"]Parameters!Rejected.Value.ToString()[/font] with [font="Times New Roman"]CStr(Parameters!Rejected.Value)[/font]. Looks like both the true and the false argument are evaluated before calling the Iif function.

    Peter

  • Yip - as I've since found out both expressions are always evaluated. I solved it by writing a small function in the Report/Parameters/Code tab. Great way to learn VB - in that little box with no support what-so-ever.

  • I just gave CStr(Parameters!Rejected.Value) a go since its a lot more convenient than writing a custom function. However what I forgot is that it doesn't allow you to choose what to display instead of null - which I wanted to do - so I'm going with my custom function for now. So in the Code tab I added the following:

    Public Shared Function HandleNull(ByVal Param As Microsoft.ReportingServices.ReportProcessing.ReportObjectModel.Parameter) As String

    If Param.Value Is Nothing Then

    Return "All"

    Else

    Return Param.Value.ToString()

    End If

    End Function

    and then in my text box I call it as:

    Code.HandleNull(Parameters!Rejected)

  • Your initial expression returned the string "Null" in case the parameter was null. Just replace the "Null" string with "All":

    =IIf(IsNothing(Parameters!Rejected.Value), "All", CStr(Parameters!Rejected.Value))

    There's no need for VB if i look at your function.

    Peter

  • Ar... good point batman... thanks for that.

Viewing 6 posts - 1 through 5 (of 5 total)

You must be logged in to reply to this topic. Login to reply