SqlDataReader.IsDBNull(Int32) Method
Definition
Gets a value that indicates whether the column contains non-existent or missing values.
public:
virtual bool IsDBNull(int i);
public bool IsDBNull (int i);
abstract member IsDBNull : int -> bool
override this.IsDBNull : int -> bool
Public Function IsDBNull (i As Integer) As Boolean
Parameters
- i
- Int32
The zero-based column ordinal.
Returns
Implements
Remarks
Call this method to check for null column values before calling the typed get methods (for example, GetByte, GetChar, and so on) to avoid raising an error.
using System;
using System.Data;
using System.Data.SqlClient;
class Program {
static void Main(string[] args) {
using (var connection = new SqlConnection(@"Data Source=(local);Initial Catalog=AdventureWorks2012;Integrated Security=SSPI")) {
var command = new SqlCommand("SELECT p.FirstName, p.MiddleName, p.LastName FROM HumanResources.Employee AS e" +
" JOIN Person.Person AS p ON e.BusinessEntityID = p.BusinessEntityID;", connection);
connection.Open();
var reader = command.ExecuteReader();
while (reader.Read()) {
Console.Write(reader.GetString(reader.GetOrdinal("FirstName")));
// display middle name only of not null
if (!reader.IsDBNull(reader.GetOrdinal("MiddleName")))
Console.Write(" {0}", reader.GetString(reader.GetOrdinal("MiddleName")));
Console.WriteLine(" {0}", reader.GetString(reader.GetOrdinal("LastName")));
}
connection.Close();
}
}
}
Imports System.Data
Imports System.Data.SqlClient
Module Module1
Sub Main()
Using connection As New SqlConnection("Data Source=(local);Initial Catalog=AdventureWorks2012;Integrated Security=SSPI")
Dim command As New SqlCommand("SELECT p.FirstName, p.MiddleName, p.LastName FROM HumanResources.Employee AS e" & _
" JOIN Person.Person AS p ON e.BusinessEntityID = p.BusinessEntityID;", connection)
connection.Open()
Dim reader As SqlDataReader = command.ExecuteReader()
While reader.Read()
Console.Write(reader.GetString(reader.GetOrdinal("FirstName")))
' display middle name only of not null
If Not reader.IsDBNull(reader.GetOrdinal("MiddleName")) Then
Console.Write(" {0}", reader.GetString(reader.GetOrdinal("MiddleName")))
End If
Console.WriteLine(" {0}", reader.GetString(reader.GetOrdinal("LastName")))
End While
connection.Close()
End Using
End Sub
End Module