I implemented a very small, basic data access layer for my web application.
It works just fine, except for this one bug.
One of my methods returns an abstracted dataset. To accomodate X number of
input parameters, I created a function signature that accepts a ParamArray
of SqlParameters as well as the name of the stored proc. In the body of the
function I loop through the param array and append each object to the
Parameters collection of my Command object.
The problem comes up when I try to append a SqlParameter object that I have
already used in a previous call, that is also an argument for the next
stored procedure. For example, I have:
dim objParam1 as New SqlParameter("@userid", intUserid)
dim objDS as DataSet
objDS = objDAL.GetDataSet("storedprocname", objParam1)
' do some stuff with the dataset, now try a new query, different proc, same
parameter
objDS.clear()
objDS = objDAL.GetDataSet("anotherprocname", objParam1)
The error returned is something like "There is already a parameter named
objParam1 in the SqlParametersCollcetion.
Prior to adding each parameter, I check its count and, if greater than 0,
remove each item before appending the new params. In debugging the count is
always 0, so how can there be an SqlParameter object in its collection?
' create our command object with the passed in ProcedureName.
' and sqlparameter object.
Dim objCommand As New SqlCommand(ProcedureName, Me.Connection)
Dim sqlParam As SqlParameter
objCommand.CommandType = CommandType.StoredProcedure
Me.LocalCommand = objCommand
If objCommand.Parameters.Count > 0 Then
' in case any parameters are hanging around, clear them out
For Each sqlParam In objCommand.Parameters
objCommand.Parameters.Remove(sqlParam)
Next
End If
objCommand.Parameters.Clear()
' add the parameters passed in from the ParamArray
' into the command's parameters collection.
For Each sqlParam In DataParameters
sqlParam = objCommand.Parameters.Add(sqlParam) ' ERROR THROWN HERE
Next
What element am I missing please? This has me bending my brain pretty badly.
Thank you in advance.
