什么是VB.Net"IsDBNull"的C#等价物

Question

在VB.Net中你可以写:

If Not IsDBNull(oCustomerNameDataRow(0)) Then
    cbCustomerName.Items.Add(oCustomerNameDataRow(0).ToString
End If

C#中的方法IsDBNull相当于什么？

Answer 1

if (!DBNull.Value.Equals(oCustomerNameDataRow[0]))
{
  //something
}

MSDN(DBNull.Value)

Answer 2

我会说相当于位于Microsoft.VisualBasic汇编中的IsDBNull方法(Microsoft.VisualBasic.Information)

Public Function IsDBNull(ByVal Expression As Object) As Boolean
    If Expression Is Nothing Then
        Return False
    ElseIf TypeOf Expression Is System.DBNull Then
        Return True
    Else
        Return False
    End If
End Function

Dim result As Boolean = IsDBNull(Nothing)

是位于mscorlib汇编中的IsDBNull方法(System.Convert):

public static bool IsDBNull(object value) {
    if (value == System.DBNull.Value) return true;
    IConvertible convertible = value as IConvertible;
    return convertible != null? convertible.GetTypeCode() == TypeCode.DBNull: false;
}

bool result = System.Convert.IsDBNull(null);