c# - Clean a DataTable in a loop moving used items to two other DataTables -

this question exact duplicate of:

• collection modified; enumeration operation might not execute on except operation 1 answer

i have main datatable called dtmain , 2 child datatables dtsuccess , dtfail. in while loop has 10 second delay in each iteration items in dtmain added dtsuccess , dtfail. in each iteration dtmain clean in other 2 lists.

i put code have tried here unfortunately not work.

while (dtmain.rows.count > 0) {    var query = dt.asenumerable().except(dtsuccess.asenumerable(), datarowcomparer.default)                  .asenumerable().except(dtfail.asenumerable(), datarowcomparer.default);    if (dtmain.asenumerable().any())         dtmain = query.copytodatatable();    thread.sleep(10000); } 

i have received exceptions such as:

collection modified; enumeration operation might not execute

and invalidoperationexception

the source contains no datarows

try looping on variable (this solve collection modified problem) :

int = dtmain.rows.count ;  while ( > 0) {    var query = dt.asenumerable().except(dtsuccess.asenumerable(), datarowcomparer.default)                  .asenumerable().except(dtfail.asenumerable(), datarowcomparer.default);    if (dtmain.asenumerable().any())         dtmain = query.copytodatatable();    thread.sleep(10000);    = dtmain.rows.count ; }