How to reverse columns order in DataTable uisng C# and VB.Net

Please refer below code

C#

protected void Page_Load(object sender, EventArgs e)
{
    DataTable dt = new DataTable();
    dt.Columns.AddRange(new DataColumn[3] 
    { 
        new DataColumn("Id"), 
        new DataColumn("Name"),
        new DataColumn("Country") 
    });
    dt.Rows.Add(1, "John Hammond", "United States");
    dt.Rows.Add(2, "Mudassar Khan", "India");
    dt.Rows.Add(3, "Suzanne Mathews", "France");
    dt.Rows.Add(4, "Robert Schidner", "Russia");

    ReverseDataTableColumns(dt);
}

private DataTable ReverseDataTableColumns(DataTable sourceDataTable)
{
    if(sourceDataTable.Rows.Count > 0)
    {
       DataTable dtReversed = new DataTable();
       var se = sourceDataTable.Columns.Cast<DataColumn>().Reverse().ToArray();
       dtReversed.Columns.AddRange(sourceDataTable.Columns.Cast<DataColumn>().Reverse().Select(x => new DataColumn(x.ColumnName)).ToArray());
       for (int j = 0; j < sourceDataTable.Rows.Cast<DataRow>().Select(x => x.ItemArray.Reverse()).Count(); j++)
       {
           dtReversed.Rows.Add();
           var row = sourceDataTable.Rows.Cast<DataRow>().Select(x => x.ItemArray.Reverse()).ElementAt(j);           
           for (int k = 0; k < row.Count(); k++)
           {
              dtReversed.Rows[j][k] = row.ElementAt(k);
           }
       }
     return dtReversed;
    }else
    {
       return sourceDataTable;
    }    
}

VB

Protected Sub Page_Load(sender As Object, e As EventArgs)
	Dim dt As New DataTable()
	dt.Columns.AddRange(New DataColumn(2) {New DataColumn("Id"), New DataColumn("Name"), New DataColumn("Country")})
	dt.Rows.Add(1, "John Hammond", "United States")
	dt.Rows.Add(2, "Mudassar Khan", "India")
	dt.Rows.Add(3, "Suzanne Mathews", "France")
	dt.Rows.Add(4, "Robert Schidner", "Russia")

	ReverseDataTableColumns(dt)
End Sub

Private Function ReverseDataTableColumns(sourceDataTable As DataTable) As DataTable
	If sourceDataTable.Rows.Count > 0 Then
		Dim dtReversed As New DataTable()
		Dim se = sourceDataTable.Columns.Cast(Of DataColumn)().Reverse().ToArray()
		dtReversed.Columns.AddRange(sourceDataTable.Columns.Cast(Of DataColumn)().Reverse().[Select](Function(x) New DataColumn(x.ColumnName)).ToArray())
		For j As Integer = 0 To sourceDataTable.Rows.Cast(Of DataRow)().[Select](Function(x) x.ItemArray.Reverse()).Count() - 1
			dtReversed.Rows.Add()
			Dim row = sourceDataTable.Rows.Cast(Of DataRow)().[Select](Function(x) x.ItemArray.Reverse()).ElementAt(j)
			For k As Integer = 0 To row.Count() - 1
				dtReversed.Rows(j)(k) = row.ElementAt(k)
			Next
		Next
		Return dtReversed
	Else
		Return sourceDataTable
	End If
End Function

I hope this will help you out