The enumerated DataReader returns incomplete information for batch queries that have different schemas (308625)

MORE INFORMATION

Steps to Reproduce the Behavior

1. Start Microsoft Visual Studio .NET.
2. Create a new Windows Application project in Visual Basic .NET. Form1 is added to the project by default.
3. Make sure that your project contains a reference to the System.Data namespace, and add a reference to this namespace if it does not.
4. Place a Button control on Form1. Button1 is added by default.
5. Use the Imports statement on the System, System.Data, System.Data.Common, System.Collections and System.Data.SqlClient namespaces so that you are not required to qualify declarations in those namespaces later in your code.

   Imports System
   Imports System.Data
   Imports System.Data.Common
   Imports System.Collections
   Imports System.Data.SqlClient
   					

6. In the Code window, add the following code after the "Windows Form Designer generated code" region:

   Private Sub Button1_Click(ByVal sender As System.Object, _
      ByVal e As System.EventArgs) Handles Button1.Click
   
      Dim cn As New SqlConnection( _
          "server=servername;uid=sa;pwd=;database=Northwind")
      cn.Open()
      Dim cm As New System.Data.SqlClient.SqlCommand( _
          "SELECT FirstName FROM Employees WHERE EmployeeId = 1;" & _
          "SELECT FirstName, LastName FROM Employees WHERE " & _
          "EmployeeId = 2", cn)
   
      Dim dr As System.Data.SqlClient.SqlDataReader
      dr = cm.ExecuteReader
   
      Dim rEnum As System.Data.Common.DbEnumerator = _
         CType(CType(dr, System.Collections.IEnumerable).GetEnumerator(), _
         DbEnumerator)
   
      Debug.WriteLine("rEnum.MoveNext = " & rEnum.MoveNext())
   
      Dim record1 As DbDataRecord = (CType(rEnum.Current, DbDataRecord))
      Debug.WriteLine(record1.FieldCount)
      Debug.WriteLine(" The number of fields in this dataRecord " & _
          record1.FieldCount)
      Debug.WriteLine("The value of the first field is " & _
          record1.GetValue(0))
   
      dr.NextResult()
   
      rEnum.MoveNext()
   
      Dim record2 As DbDataRecord = (CType(rEnum.Current, DbDataRecord))
   
      ' Note that the DataRecord only displays a field count of 1,
      ' which is incorrect
      Debug.WriteLine("The number of fields in this DataRecord " & _
          record2.FieldCount)
      Debug.WriteLine("The value of the first field is = " & _
          record2.GetValue(0))
   
      dr.Close()
      cn.Close()
   End Sub
   					

7. Modify the connection string as appropriate for your environment.
8. Save your project. On the Debug menu, click Start to run your project.
9. Click Button1. Press the CTRL+ALT+O key combination to view the Output window. Notice that the number of fields in the second DataRecord (record2) is 1, which is incorrect, and the LastName field is missing.
10. To work around this behavior, add LastName to the SELECT statement to change the schema of the first query so that it matches the second query. Notice that the number of fields is correct.