c# - Oracle.DataAccess DataRow.Field<decimal> InvalidCastException -

in code using system.data.oracleclient ora database connection. replace library (because obsolete) oracle.dataaccess. unfortunately found datarow.field() throws invalidcastexception. same behavior (decimal)x.rows[0]["colume_name"]. not have issue system.data.oracleclient.

here code example

using (var oracleconnection = new oracleconnection(connectionstring)) {     using (var command = new oraclecommand("select * tr", oracleconnection))     {         var result = new datatable();         var adapter = new oracledataadapter(command);         adapter.fill(result);         console.writeline(result.rows[0].field<decimal>("tr_seq_num"));         //console.writeline((decimal)result.rows[0]["tr_seq_num"]);     } } 

tr_seq_num has number(8,0) datatype , full exception is:

system.invalidcastexception: specified cast not valid.    @ system.data.datarowextensions.unboxt`1.valuefield(object value) 

code example working system.data.oracleclient not oracle.dataaccess

i know can use convert.changetype wonder if there way have same behavior system.data.oracleclient. refactoring of of code time expensive.

the value in database not decimal , boxed int (the 'value' parameter in error message) cannot cast decimal, despite casting int decimal being ok. this answer leads more info.

you can see in action this:

void main() {     int anint = 5;     object boxedint = (object)anint;     decimal unboxed = convert.todecimal(boxedint); //5     decimal unboxed2 = (decimal)boxedint; //invalidcastexception } 

if @ unbox.valuefield method, does...

  private static t valuefield(object value)   {     if (dbnull.value == value)       throw datasetutil.invalidcast(strings.datasetlinq_nonnullablecast((object) typeof (t).tostring()));     return (t) value;   } 

basically you'll need to

convert.todecimal(rows[0]["tr_seq_num"]);