Or use a typed list, or use: (all need an entity defined for table1)
// ResultsetFields is a class generated into the HelperClasses namespace
ResultsetFields fields = new ResultsetFields(5);
fields.DefineField(Table1FieldIndex.Column1, 0, "Column1");
fields.DefineField(Table1FieldIndex.Column2, 1, "Column2");
fields.DefineField(Table1FieldIndex.Column3, 2, "Column3");
fields.DefineField(Table1FieldIndex.Column4, 3, "Column4");
fields.DefineField(Table1FieldIndex.Column5, 4, "Column5");
DataTable tlist = new DataTable();
TypedListDAO dao = new TypedListDAO();
dao.GetMultiAsDataTable(fields, tlist, 0, null, null, null, false, null, null, 0, 0);
If you're not using hte 1.0.2004.1 runtimes, first released on 24-sep-2004, you will have to remove the 0,0 at the end of GetMultiAsDataTable() (check the signature for correctness)