SqlDataSource.SelectParameters with variable or session from MySqlDataReader return nothing

Question

User-1258024267 posted

Sorry for my english !

When I click on button 

Protected Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click

ReadMyData(ConfigurationManager.ConnectionStrings("myconnection").ConnectionString)

End Sub

After

Public Sub ReadMyData(myConnString As String)

Dim myVariable As String = ""

Dim myConnection As New MySqlConnection(myConnString)
Dim myCommand As New MySqlCommand("mystoreprocedure", myConnection)

myCommand.CommandType = CommandType.StoredProcedure
myCommand.Parameters.AddWithValue("@pMyparam", "9063")

myConnection.Open()
Dim myReader As MySqlDataReader
myReader = myCommand.ExecuteReader()
' Always call Read before accessing data.
While myReader.Read()

myVariable  = myReader.GetString(0)

End While

Session("mySession") = myVariable
Me.SqlDataSource.SelectParameters(0).DefaultValue = Session("mySession")
Me.SqlDataSource.DataBind()

myReader.Close()
myConnection.Close()

End Sub 

My SqlDataSource and my datalist is always get nothing, I check everthing my datareader return 1234 and  myVariable  = 123

if I put like 
Me.SqlDataSource.SelectParameters(0).DefaultValue = "1234" instead is work perfectly.

Please help me , thank you 

Answer 1

User281315223 posted

Have you tried placing a breakpoint and actually stepping through this code as it executes? It could be possible that your actual value being returned isn't what is being expected :

Protected Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
    ' This should be straight-forward, passing a connection string to a connection '
    ReadMyData(ConfigurationManager.ConnectionStrings("myconnection").ConnectionString)
End Sub

Public Sub ReadMyData(myConnString As String)
   Dim myVariable As String = ""

   Using myConnection As New MySqlConnection(myConnString)
      ' Open your connection '
      myConnection.Open()
 
      ' Build a command to execute using your stored procedure '
      Using myCommand As New MySqlCommand("mystoreprocedure", myConnection)
         ' Indicate this is a stored procedure '
         myCommand.CommandType = CommandType.StoredProcedure

         ' Add your parameters '
         myCommand.Parameters.AddWithValue("@pMyparam", "9063") 

         ' Read through your results '
         Using myReader = myCommand.ExecuteReader()
             While myReader.Read()
                  ' This will continually overwrite the myVariable value. Is this what you want? '
                  myVariable  = myReader.GetString(0)
             End While
         End Using
      End Using
      ' Update your data sources (why are you storing it in the Session here? Just use the myVariable value. '
      Session("mySession") = myVariable
      Me.SqlDataSource.SelectParameters(0).DefaultValue = myVariable
      Me.SqlDataSource.DataBind()
   End Using 
End Sub 

Answer 2

User-1258024267 posted

Thanks a lot for your time, the was  wrong data from database : so many time lost :(  but I learn ...