SqlDataReader Object provides a connection oriented data access to the SQL Server data Sources. ExecuteReader() in the SqlCommand Object send the SQL statements to SqlConnection Object and populate a SqlDataReader Object based on the SQL statement.
Dim sqlReader As SqlDataReader = sqlCmd.ExecuteReader()
When the ExecuteReader method in SqlCommand Object execute , it instantiate a SqlClient.SqlDataReader Object. When started to read from a DataReader it should always be open and positioned prior to the first record. The Read() method in the DataReader is used to read the rows from DataReader and it always moves forward to a new valid row, if any row exist .
SqlDataReader.Read()
Imports System.Data.SqlClient
Public Class Form1
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
Dim connetionString As String
Dim sqlCnn As SqlConnection
Dim sqlCmd As SqlCommand
Dim sql As String
connetionString = "Data Source=ServerName;Initial Catalog=DatabaseName;User ID=UserName;Password=Password"
sql = "Your SQL Statement Here , like Select * from product"
sqlCnn = New SqlConnection(connetionString)
Try
sqlCnn.Open()
sqlCmd = New SqlCommand(sql, sqlCnn)
Dim sqlReader As SqlDataReader = sqlCmd.ExecuteReader()
While sqlReader.Read()
MsgBox(sqlReader.Item(0) & " - " & sqlReader.Item(1) & " - " & sqlReader.Item(2))
End While
sqlReader.Close()
sqlCmd.Dispose()
sqlCnn.Close()
Catch ex As Exception
MsgBox("Can not open connection ! ")
End Try
End Sub
End Class