nullable object must have value in vb.net -please help me friends

Question

User-916396441 posted

Hi friends,

I am  getting "nullable object must have value".How can i resloved the issue. i am new to .net

The code shown below

InDto

Public Property FromDate As Nullable(Of Date)<o:p></o:p>

Public Property ToDate As Nullable(Of Date)

Public Shared Function ValidateBizRulXXX(dto As DTO.NameofDTO) As Boolean

        Dim isValid As Boolean

        Dim Datevalidate As New DateValidattion

 If Datevalidate.CompareDate(dto.FromDate.Value, dto.ToDate.Value, DateValidattion.DateValidation.Date1GreaterThanorEqualtoDate2, 0) OrElse

  Datevalidate.CompareDate(dto.FromDate.Value, Date.Today, DateValidattion.DateValidation.Date1GreaterThanDate2, 0) OrElse

   Datevalidate.CompareDate(dto.ToDate.Value, Date.Today, DateValidattion.DateValidation.Date1GreaterThanDate2, 0) Then

     BrokenRulesContext.GetBrokenRulesFromContext.AddBrokenRule(New BrokenRule(BIZRUL_VIOLATION_MESSAGE_ABCDE))

                    isValid = False

                Else

                    isValid = True

                End If

        End If

        Return isValid

    End Function

Answer 1

User-158764254 posted

you're attempting to read the Value property of FromDate and ToDate but you never assigned a value to either of them.

Answer 2

User-916396441 posted

 If Datevalidate.CompareDate(dto. FromDate.Value, dto. ToDate.Value, DateValidattion.DateValidation.Date1GreaterThanorEqualtoDate2, 0) OrElse

                  Datevalidate.CompareDate(dto. FromDate.Value, Date.Today, DateValidattion.DateValidation.Date1GreaterThanDate2, 0) OrElse

            Datevalidate.CompareDate(dto. ToDate.Value, Date.Today, DateValidattion.DateValidation.Date1GreaterThanDate2, 0) Then

                    BrokenRulesContext.GetBrokenRulesFromContext.AddBrokenRule(New BrokenRule(BIZRUL_VIOLATION_MESSAGE_adbc))

                    isValid = False

                Else

                    isValid = True

                End If

            End If

        End If

 

 

Indto:

   Public Property FromDate As Nullable(Of Date)

   Public Property ToDate As Nullable(Of Date)

 

 

InASPX  Page

 <ABC:wPanel ID="Date" CssClass="KeepInLine" runat="server">

                <ABC:DateTextBox ID="FromDate" runat="server" Caption="From" CssClass="dateControlSmall"

                    ControlRowCssClass="KeepInLine" />

                <ABC:wDateTextBox ID="ToDate" runat="server" Caption="To" CssClass="dateControlSmall"

                    ControlRowCssClass="KeepInLine" /><ABC:wPanel>

Answer 3

User-158764254 posted

You cannot call this: dto.FromDate.Value

If dto.FromDate is null.

If you attempt to read the Value property of a Nullable when that Nullable is still null, then you wil get the error you're seeing.

You can check the HasValue property before trying to read the Value

http://msdn.microsoft.com/en-us/library/sksw8094.aspx