Cannot update Access database in C# -

i trying build update button able edit data textbox. using access database , having problems , cannot update it.

bellow code:

private void cmdupdate_click(object sender, eventargs e) {     try     {         con = new oledbconnection(cs.dbconn);         con.open();          string queryupdate = @"update tblfixing set title=@title, codebefore=@codebefore, codafter=@codafter, exp=@exp, example=@example, notes=@notes fixid=@fixid";         cmd = new oledbcommand(queryupdate);         cmd.connection = con;          cmd.parameters.add(new oledbparameter("@fixid", oledbtype.wchar, 20, "fixid"));         cmd.parameters.add(new oledbparameter("@title", oledbtype.wchar, 255, "title"));         cmd.parameters.add(new oledbparameter("@codebefore", oledbtype.wchar, 0, "codebefore"));         cmd.parameters.add(new oledbparameter("@codafter", oledbtype.wchar, 0, "codafter"));         cmd.parameters.add(new oledbparameter("@exp", oledbtype.wchar, 0, "exp"));         cmd.parameters.add(new oledbparameter("@example", oledbtype.wchar, 0, "example"));         cmd.parameters.add(new oledbparameter("@notes", oledbtype.wchar, 255, "notes"));          cmd.parameters["@fixid"].value = cmbid.text.trim();         cmd.parameters["@title"].value = txttitulo.text.trim();         cmd.parameters["@codbefore"].value = rchcodbefore.text.trim();         cmd.parameters["@codafter"].value = rchcodafter.text.trim();         cmd.parameters["@exp"].value = rchexplicacao.text.trim();         cmd.parameters["@example"].value = rchexemplo.text.trim();         cmd.parameters["@notes"].value = rchnotas.text.trim();          cmd.executenonquery();         messagebox.show("successful updated", "information", messageboxbuttons.ok, messageboxicon.information);          con.close();     }     catch (exception ex)     {         messagebox.show("error\ndetails: " + ex.message, "error", messageboxbuttons.ok, messageboxicon.error);     } } 

i debug code , data not update. should do?

oledb doesn't use named parameters. appear in index order.

you have @fixid parameter first parameter added collection, when @ sql string, it's last parameter in string.

change parameter order:

cmd.parameters.add(new oledbparameter("@title", oledbtype.wchar, 255, "title")); cmd.parameters.add(new oledbparameter("@codebefore", oledbtype.wchar, 0, "codebefore")); cmd.parameters.add(new oledbparameter("@codafter", oledbtype.wchar, 0, "codafter")); cmd.parameters.add(new oledbparameter("@exp", oledbtype.wchar, 0, "exp")); cmd.parameters.add(new oledbparameter("@example", oledbtype.wchar, 0, "example")); cmd.parameters.add(new oledbparameter("@notes", oledbtype.wchar, 255, "notes")); cmd.parameters.add(new oledbparameter("@fixid", oledbtype.wchar, 20, "fixid"));