Problems calling a Stored Procedure from VB.NET

Question

As you can probably very soon see, I am a complete newbie at VB.NET, and I am having some trouble getting output from a stored procedure in SQL Server 2005.

This is the code I use

    Dim con As New SqlConnection
    Dim cmd As New SqlCommand("esp_getDates", con)
    Dim par As New SqlParameter("@PlaceID", SqlDbType.Int, 3906)
    con.ConnectionString = "Data Source=localhost\SQLEXPRESS;Initial Catalog=ProgramDB;User ID=test;Password=test"
    con.Open()
    cmd.CommandType = CommandType.StoredProcedure
    cmd.Parameters("@PlaceID").Direction = ParameterDirection.Output
    cmd.ExecuteNonQuery()
    con.Close()

I get the error;

An SqlParameter with ParameterName '@PlaceID' is not contained by this SqlParameterCollection.

Does anyone see what I'm doing wrong / have any suggestions how I can fix it? Code examples would be very helpful and any help is much appreciated.

Answer 1

You aren't actually adding the parameter to the cmd.Parameters collection:

cmd.Parameters.Add(par)

Alternatively, just add the parameter without instantiating the Parameter object explicitly:

cmd.Parameters.Add("@PlaceID", SqlDbType.Int)
cmd.Parameters("@PlaceID").Value = 3906

Also, I'd follow the principle of using a variable as close to the declaration as possible and reorganize things this way:

Dim con As New SqlConnection("Data Source=localhost\SQLEXPRESS;Initial Catalog=ProgramDB;User ID=test;Password=test")
con.Open()

Dim cmd As New SqlCommand("esp_getDates", con)

Try
    cmd.CommandType = CommandType.StoredProcedure
    cmd.Parameters.Add("@PlaceID", SqlDbType.Int)
    cmd.Parameters("@PlaceID").Value = 3906
    cmd.ExecuteNonQuery()

Finally
    If cmd IsNot Nothing Then cmd.Dispose()
    If cn IsNot Nothing AndAlso cn.State <> ConnectionState.Closed Then cn.Close()
End Try