asp.net - C#: Object reference not set to an instance of an object -

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i following error:

object reference not set instance of object

this c sharp code:

      datatable tableacces = dsacces.tables["dsprinteracces"];       datatable tablemdf = dsacces.tables["dsprintermdf"];       datarow newrow = null;         foreach(datarow dr in tableacces.rows)        {            newrow = tablemdf.newrow();          newrow["printer_id"] = dr["printer_id"];         newrow["merk"] = dr["merk"];         newrow["model"] = dr["model"];         newrow["lokaal_id"] = dr["lokaal_id"];          tablemdf.rows.add(newrow);       }        damdf.update(dsmdf, "dsprintermdf");       lblsucces.text = "gelukt. de tabel printers overgezet.";     }

in line, throws error:

newrow = tablemdf.newrow();

thanks lot,

vincent

tablemdf null then. need find out why dsacces.tables["dsprintermdf"] returning null @ top.


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