问题描述:

I'm trying to populate a listview with varBinary(max) values. Well, I actually need to write each varBinary into a csv file and the table consists of 100 000 odd rows.

I just don't know how to retrieve the datatype!

 Sub getInformation()

Try

If Not String.IsNullOrWhiteSpace(connString) Then

Using cn As SqlConnection = New SqlConnection(connString)

cn.Open()

Using cmd As SqlCommand = New SqlCommand()

cmd.Connection = cn

Dim qry As String

qry = String.Format("SELECT [varBinaryField] FROM [dbX].[dbo].[tableX]")

cmd.CommandText = qry

cmd.CommandTimeout = 0

Using myReader As SqlDataReader = cmd.ExecuteReader(CommandBehavior.CloseConnection)

While (myReader.Read())

ListView1.Items.Add(myReader.get?WHAT?(0)) 'Help needed here.

End While

End Using

End Using

End Using

End If

Catch ex As Exception

MsgBox(ex.Message)

End Try

End Sub

Heres an example of one of the varBinary codes :

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

网友答案:
    Using cn As SqlConnection = New SqlConnection("Server=.;Database=test;Trusted_Connection=True;")
        cn.Open()
        Using cmd As SqlCommand = New SqlCommand()
            cmd.Connection = cn
            Dim qry As String
            qry = String.Format("SELECT field FROM test.dbo.test")
            cmd.CommandText = qry
            cmd.CommandTimeout = 0
            Dim oFileStream As System.IO.FileStream
            oFileStream = New System.IO.FileStream("c:\bytes.txt", System.IO.FileMode.Append)
            Using myReader As SqlDataReader = cmd.ExecuteReader(CommandBehavior.CloseConnection)
                While (myReader.Read())
                    Dim data As Byte() = myReader(0)
                    oFileStream.Write(data, 0, data.Length)
                End While
                oFileStream.Close()
            End Using
        End Using
    End Using

UPDATE: here is: another example on VB.NET

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