• Articolo

Metodo IsNull

Returns a value that indicates whether the value of the specified column is nullNothingnullptrunitriferimento Null (Nothing in Visual Basic)..

Spazio dei nomi:  Microsoft.SqlServer.Dts.Pipeline
Assembly:  Microsoft.SqlServer.TxScript (in Microsoft.SqlServer.TxScript.dll)

Sintassi

'Dichiarazione
Protected Function IsNull ( _
    ColumnIndex As Integer _
) As Boolean
'Utilizzo
Dim ColumnIndex As Integer
Dim returnValue As Boolean

returnValue = Me.IsNull(ColumnIndex)

protected bool IsNull(
    int ColumnIndex
)

protected:
bool IsNull(
    int ColumnIndex
)

member IsNull : 
        ColumnIndex:int -> bool 

protected function IsNull(
    ColumnIndex : int
) : boolean

Parametri

Valore restituito

Tipo: System. . :: . .Boolean
true if the value of the specified column is nullNothingnullptrunitriferimento Null (Nothing in Visual Basic).; otherwise, false.

Osservazioni

The Script component developer does not use the ScriptBuffer class directly, but indirectly, through the derived classes in the BufferWrapper project item that represent the component's input and outputs.

The developer does not have to use the IsNull method, because the derived classes contain a <ColumnX>_IsNull property for each column.

Esempi

The following sample code from the autogenerated BufferWrapper project item demonstrates how the Script component uses the IsNull method.

    Public Property [city_IsNull] As Boolean
        Get
            Return IsNull(1)
        End Get
        Set
            SetNull(1)
        End Set
    End Property