A field that contains only NULL values is not copied into a new DataSet when you use the GetXml method to copy data from one DataSet to another DataSet

Steps to Reproduce the Behavior

1. Start Microsoft Visual Studio .NET.
2. Create a new Windows application in Visual Basic .NET.
3. Make sure that your project contains a reference to the System.Data namespace; add a reference to this namespace if it does not.
4. Drag a Button control and two DataGrid controls from the toolbox to Form1.
5. Change the Name property of the Button control to btnTest, and then change the Text property of the Button control to Test.
6. Use the Imports statement on the System.Data, the System.Data.SqlClient, and the System.IO namespaces so that you are not required to qualify declarations in those namespaces later in your code. Add the following code to the "General Declarations" section of Form1:

   Imports System.Data
   Imports System.Data.SqlClient
   Imports System.IO
   					

7. Add the following code in the btnTest_Click event:

           Dim myConnString As String = _
               "User ID=myUID;password=myPWD;Initial Catalog=Northwind;Data Source=mySQLServer"
           Dim mySelectQuery As String = "SELECT * FROM Customers WHERE Region IS NULL"
           Dim con As New SqlConnection(myConnString)
           Dim daCust As New SqlDataAdapter(mySelectQuery, con)
           Dim ds As New DataSet()
   
           daCust.Fill(ds, "Cust") 'Fill the initial DataSet.
           DataGrid1.DataSource = ds 
           DataGrid1.DataMember = "Cust"
           Dim ds1 As New DataSet()
   
           Dim sr As New StringReader(ds.GetXml)
           ds1.ReadXml(a)
           'Comment out the previous two lines and uncomment the next line 
           'to display columns with all NULL values.
           'ds1 = ds.Copy()
   
           DataGrid2.DataSource = ds1
           DataGrid2.DataMember = "Cust"
   					

8. Modify the connection strings as appropriate for your environment.
9. Save your project. Click Start on the Debug menu to run your project.
10. Click Test. Notice that the Region column appears in the first data grid and not in the second.
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    Resolution

11. Comment out the lines of code that use the GetXml method as follows:

            'Dim sr As New StringReader(ds.GetXml)
            'ds1.ReadXml(a)
    					

12. Uncomment the line of code that uses the Copy method as follows:

            ds1 = ds.Copy()
    					

13. Save your project. Click Start on the Debug menu to run your project again.
14. Click Test. Notice that the Region column appears in both of the data grids.

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