什麼是C＃相當於VB.Net 「IsDBNull以便」 的

Question

在VB.Net你可以寫：

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

什麼方法IsDBNull以便在C＃中等價？

Answer 1

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

MSDN (DBNull.Value)

Answer 2

我要說IsDBNull方法（Microsoft.VisualBasic.Information）的等效位於所述Microsoft.VisualBasic assembley

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IsDBNull方法（System.Convert）地處mscorlib assembley：

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);