How do I clear a dataset when the tables have existing relations?

Question

How do I clear a dataset when the tables have existing relations? I'm trying to clear a dataset between uses. Each time I load a new XML file the dataset keeps the old table names, but I'm loading an entirely new XML file so I need it cleared out. I'm trying to use ssrsReportDataSet.Tables.Clear(), but I get

"Cannot remove a table that has existing relations. Remove relations first."

I'm pretty sure there are foreign key constraints between the existing tables.

Previously I have tried walking the dataset and deleting each row from each table, but I still can't delete the tables or clear the dataset.

Private Sub btnLoadFile_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnLoadFile.Click

    Dim fd As OpenFileDialog = New OpenFileDialog()
    Dim strFileName As String

    fd.Title = "Open File Dialog"
    fd.InitialDirectory = "C:\"
    fd.Filter = "XML Files (*.xml)|*.xml|Excel Files (*.xls)|*.xlsx"
    fd.FilterIndex = 1
    fd.RestoreDirectory = True

    If fd.ShowDialog() = DialogResult.OK Then


        ' Clear data set
        ssrsReportDataSet.Tables.Clear()


        strFileName = fd.FileName
        lblFilePath.Text = strFileName

        'Load dataset from XML file
        ssrsReportDataSet.ReadXml(strFileName)

        ' Set dropdown values
        For n As Integer = 0 To ssrsReportDataSet.Tables.Count - 1

            tableSelecter.Items.Add(ssrsReportDataSet.Tables(n).TableName)
        Next

        ' Load datagrid
        DataGridViewXml.DataSource = ssrsReportDataSet
        DataGridViewXml.DataMember = ssrsReportDataSet.Tables(0).TableName

        tableSelecter.SelectedIndex = 0

    End If
End Sub

Answer 1

If you don't need anymore the previous DataSet but want to use the same global variable then just reinitialize it

    ssrsReportDataSet = new DataSet();

And, no there is no need to Dispose a DataSet.