SQL - uniqueidentifier

hvad giver

Dim Uniq_id As Guid = CType(rdr(0),Guid)
Console.WriteLine(Uniq_id)

?

Specified cast is not valid.

hvad er rdr(0).GetType.Name ?

følgende virker hos mig:

Imports System
Imports System.IO
Imports System.Data
Imports System.Data.SqlClient

Class MainClass
    Public Shared Sub Main(ByVal args As String())
        Dim con As SqlConnection = New SqlConnection ("server=ARNEPC3;Integrated Security=SSPI;database=Test")
        con.Open
        Dim cre As SqlCommand = New SqlCommand ("CREATE TABLE guidtest (id UNIQUEIDENTIFIER PRIMARY KEY,data VARCHAR(50))", con)
        cre.ExecuteNonQuery
        Dim ins As SqlCommand = New SqlCommand ("INSERT INTO guidtest VALUES(NEWID(), 'bla bla')", con)
        ins.ExecuteNonQuery
        Dim sel As SqlCommand = New SqlCommand ("SELECT * FROM guidtest", con)
        Dim rdr As SqlDataReader = sel.ExecuteReader
        While rdr.Read
            Dim id As Guid = CType(rdr(0), Guid)
            Dim data As String = CType(rdr(1), String)
            Console.WriteLine(id.ToString & " " & data)
        End While
        rdr.Close
        Dim drp As SqlCommand = New SqlCommand("DROP TABLE guidtest", con)
        drp.ExecuteNonQuery
        con.Close
    End Sub
End Class

hvad er rdr(0).GetType.Name ? > det er en Double

rdr(0).GetType.Name

er typen af den første kolonne i result settet

og den er Double ikke Guid !

hvis

--------------------

Dim SLQ_string As String
        Dim con As SqlConnection = New SqlConnection("server=127.0.0.1;Integrated Security=SSPI;database=DEDB")
        con.Open()

        SLQ_string = "SELECT TOP 2 "
        SLQ_string = SLQ_string & "JobName, ActualStartTime, EndTime, IsJobActive, FinalJobStatus, FinalErrorCode, "
        SLQ_string = SLQ_string & "FinalErrorCategory, TotalDataSizeBytes, TotalRateMBMin, "
        SLQ_string = SLQ_string & "TotalNumberOfFiles, TotalNumberOfDirectories, TotalSkippedFiles,"
        SLQ_string = SLQ_string & "TotalCorruptFiles, TotalInUseFiles, JobLogFileName, JobHistoryID "
        SLQ_string = SLQ_string & "FROM dbo.JobHistorySummary "
        SLQ_string = SLQ_string & "ORDER BY ActualStartTime DESC "
        Console.WriteLine(SLQ_string.ToString)

        Dim cmd As SqlCommand = New SqlCommand(SLQ_string, con)
        Dim rdr As SqlDataReader = cmd.ExecuteReader
        While rdr.Read
            Dim JobName As String = rdr(0)
            Dim JobHistoryID As Guid = rdr(12)


            Console.WriteLine(JobName)
            Console.WriteLine(JobHistoryID.ToString)
           


        End While

----------------

så giver den mig JobName rigtig men ikke JobHistoryID den bliver 0 ?


mens der i sql databasen er "{4CEA5945-A227-4DE6-A97E-E36F0EAF10E6}"

det er mig som ikke kan tælle :( unskyld....

lig lige et svar :) UPS
skulder vist en øl eller to, tak for hjælpen

ok