[VB.NET]Datareader

[hobbes2103]

Hello!

 

Here is my code :

 

Dim myConnection As New OleDb.OleDbConnection

Dim myReader As OleDb.OleDbDataReader

Dim myConnectionString As String = "Provider=Microsoft.Jet.OLEDB.4.0;" & _

"Data Source=C:\erco\erco.mdb"

myBase = New OleDb.OleDbConnection(myConnectionString)

myBase.Open()

 

Dim myCommand As New OleDb.OleDbCommand

Dim mySelect As String = "SELECT code,name FROM articles WHERE code='1'"

myCommand = New OleDb.OleDbCommand(mySelect, myBase)

myReader = myCommand.ExecuteReader()

 

Dim str As String

While (myReader.Read())

str = myReader("name")

End While

myReader.Close()

[hobbes2103]

Now, my problem is : if "name" is empty (it is not my primary key, so sometimes there is no name), it won't work.

I would like str to get the value "".

[dynamic_sysop]

try this :

   Private Sub Button4_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button4.Click
       Dim sConnString As String = "Provider=Microsoft.Jet.OLEDB.4.0;Data Source=C:\MyDb.mdb;"
       Dim Conn As New OleDb.OleDbConnection(sConnString)

       Try
           Dim sCommand As String = "Select * From Table1"

           Conn.Open()
           Dim Command As New OleDb.OleDbCommand(sCommand, Conn)
           Dim reader As OleDb.OleDbDataReader
           reader = Command.ExecuteReader
           Dim x As Integer
           For x = 0 To reader.FieldCount - 1
               MessageBox.Show(reader.GetName(x)) '/// the names of your fields.
           Next
       Catch ex As Exception
           MessageBox.Show(ex.Message)
       Finally
           Conn.Close()
       End Try
   End Sub

it may help.

[jfackler]

       Dim str As String
       Dim myReader As OleDbDataReader
       While (myReader.Read())
           If Not IsDBNull(myReader("name")) Then
               str = myReader("name")
           Else
               str = ""

           End If

       End While
       myReader.Close()

 

 

 

Jon

[Derek Stone]

Use [msdn=System.Data.OleDb.OleDbDataReader]OleDbDataReader[/msdn].IsDbNull(), not Visual Basic's IsDbNull() function.

[hobbes2103]

Thank you!