How to get the DataField name of a BoundColumn from code-behind

Try
[VB.NET]

Dim bc As BoundColumn = CType(Me.DataGrid1.Columns(1), BoundColumn)
Response.Write(bc.DataField)

[C#]

BoundColumn bc = (BoundColumn)this.DataGrid1.Columns[1];
Response.Write(bc.DataField);