Output parameters are not returned when you run an ADO.NET command in Visual Basic

• Output parameters are returned at the end of the data stream when using a DataReader object.
• The Direction property of the parameter is not set properly.

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• When using a DataReader, you must close it or read to the end of the data before the output parameters are visible.
• Make sure that the Direction property of the parameter is set to Output, or InputOutput if the parameter is used in the procedure to both send and receive data.

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Steps to Reproduce the Behavior

1. Create a stored procedure "myProc" in the Pubs database by executing the following query in SQL Server Query Analyzer:

   CREATE proc MyProc
   @out integer OUTPUT
   AS
   Select @out = count(*) from authors
   GO
   					

2. Start Microsoft Visual Studio .NET.
3. Create a new Windows Application in Visual Basic .NET.
4. Make sure that your project contains a reference to the System.Data namespace.
5. Place two Command buttons on Form1. Change the Name property of the first button to btnDirection and the Text property to Direction. Change the Name property of the second button to btnReader and the Text property to Reader.
6. Use the Imports statement on the System and System.Data namespaces so that you are not required to qualify declarations in those namespaces later in your code. Add this to the General Declarations section of Form1.

   Imports System
   Imports System.Data.OleDb
   Imports System.Data.SqlClient
   					

7. Paste the following code in the code window after the region "Windows Form Designer generated code."
   
   Note You must replace User ID <user name> with an account that has appropriate permissions to perform these operations on the database.

       Private Sub btnDirection_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnDirection.Click
           Dim myConnString As String = _
                   "User ID=<username>;password=<strong password>;Initial Catalog=pubs;Data Source=myServer"
           Dim myConnection As New SqlConnection(myConnString)
           Dim myCommand As New SqlCommand()
   
           myCommand.CommandType = CommandType.StoredProcedure
           myCommand.Connection = myConnection
           myCommand.CommandText = "MyProc"
           myCommand.Parameters.Add("@out", OleDbType.Integer)
           'Uncomment this line to return proper output value.
           'myCommand.Parameters("@out").Direction = ParameterDirection.Output
           Try
               myConnection.Open()
               myCommand.ExecuteNonQuery()
               MessageBox.Show("Return Value : " & myCommand.Parameters("@out").Value)
           Catch ex As Exception
               MessageBox.Show(ex.ToString())
           Finally
               myConnection.Close()
           End Try
       End Sub
   
       Private Sub btnReader_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnReader.Click
           Dim myConnString As String = _
                       "User ID=<username>;password=<strong password>;Initial Catalog=pubs;Data Source=myServer"
           Dim myConnection As New SqlConnection(myConnString)
           Dim myCommand As New SqlCommand()
           Dim myReader As SqlDataReader
   
           myCommand.CommandType = CommandType.StoredProcedure
           myCommand.Connection = myConnection
           myCommand.CommandText = "MyProc"
   
           myCommand.Parameters.Add("@out", OleDbType.Integer)
           myCommand.Parameters("@out").Direction = ParameterDirection.Output
   
           Try
               myConnection.Open()
               myReader = myCommand.ExecuteReader()
   
               'Uncomment this line to return proper output value.
               'myReader.Close()
               MessageBox.Show("Return Value : " & myCommand.Parameters("@out").Value)
   
           Catch ex As Exception
               MessageBox.Show(ex.ToString())
           Finally
               myConnection.Close()
           End Try
       End Sub
   					

8. Modify the Connection string (myConnString) as appropriate for your environment.
9. Save your project. On the Debug menu, click Start to run your project.
10. Click the Direction button and you can see that an incorrect value is returned for the output parameter.
11. Uncomment the line of code that sets the Direction property for the output parameter and then run the project. Now you can see that output parameter is returned correctly when the Direction button is clicked.
12. Click the Reader button and you may see that an incorrect value is returned for the output parameter.
13. Uncomment the line of code that closes the DataReader object and then run the project. Now you can see that output parameter is returned correctly when the Reader button is clicked.

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