SqlDataReader.IsDBNull(Int32) 메서드

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정의

네임스페이스:
System.Data.SqlClient
어셈블리:
System.Data.SqlClient.dll
어셈블리:
System.Data.dll
패키지:
System.Data.SqlClient v4.8.6

열의 값이 존재하지 않거나 누락되었는지 여부를 나타내는 값을 가져옵니다.

public:
 override bool IsDBNull(int i);
public:
 virtual bool IsDBNull(int i);
public override bool IsDBNull (int i);
public bool IsDBNull (int i);
override this.IsDBNull : int -> bool
abstract member IsDBNull : int -> bool
override this.IsDBNull : int -> bool
Public Overrides Function IsDBNull (i As Integer) As Boolean
Public Function IsDBNull (i As Integer) As Boolean

매개 변수

i
Int32

열 서수(0부터 시작)입니다.

반환

Boolean

지정된 열 값이 DBNull와(과) 같으면 true이고, 그렇지 않으면 false입니다.

구현

IsDBNull(Int32)

설명

오류가 발생하지 않도록 형식화된 get 메서드(예GetByte: , GetChar등)를 호출하기 전에 null 열 값에 대해 검사 이 메서드를 호출합니다.

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

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