c# - Dapper & MS Access - Read works, Write doesn't -

let's start getting out of way: i'm stuck using ms access db , can't change it.

this works fine:

using (oledbconnection conn = connectionhelper.getconnection()) {   conn.open();   var results = conn.query<string>(     "select firstname students lastname = @lastname",      new { lastname= "smith" }   );   conn.close(); } 

this works fine:

using (oledbconnection conn = connectionhelper.getconnection()) {   oledbcommand cmd = new oledbcommand(     "update students set firstname = @firstname, city = @city lastname = @lastname",      conn   );   cmd.parameters.addwithvalue("firstname", "john");   cmd.parameters.addwithvalue("city", "somecity");   cmd.parameters.addwithvalue("lastname", "smith");    conn.open();   var result = cmd.executenonquery();   conn.close(); } 

this doesn't... executes without error sets firstname "somecity" in db , city "john":

using (oledbconnection conn = connectionhelper.getconnection()) {   conn.open();   var results = conn.query<string>(     "update students set firstname = @firstname, city = @city lastname = @lastname",      new { firstname = "john", city = "somecity", lastname = "smith" }   );   conn.close(); } 

any ideas?

edit below

dapper works if use dynamicparameters:

using (oledbconnection conn = connectionhelper.getconnection()) {   dynamicparameters parameters = new dynamicparameters();   parameters.add("firstname", "john");   parameters.add("city", "somecity");   parameters.add("lastname", "smith");    conn.open();   var result = conn.query<string>(     "update students set firstname = @firstname, city = @city lastname = @lastname",     parameters   );   conn.close(); } 

after digging, able find cause:

below createparaminfogenerator delegate dapper's sqlmapper:

    public static action<idbcommand, object> createparaminfogenerator(identity identity)     {          // code above here         ienumerable<propertyinfo> props = type.getproperties().orderby(p => p.name);  

the props unanimous param gets re-ordered orderby(p => p.name), moves city upfront.

new { firstname = "john", city = "somecity", lastname = "smith" } 

props being added idbcommand parameters order important.

if comment out orderby() clause, works.

i tested dynamicparameters , intentionally re-ordered attributes move city upfront:

        var parameters = new dynamicparameters();         parameters.add("city", "somecity");         parameters.add("firstname", "john");         parameters.add("lastname", "smith");          var result = dbconnection.query<string>(           "update students set firstname = @firstname, city = @city lastname = @lastname",           parameters         ); 

the above did not work well, order of attributes reason!

i guess can modify local copy of sqlmapper , remove orderby() , wait official verdict marc...

hope helps.