c# - How to get values from Class -

i building c# wpf app. app contains listview multiple column. added column , binding in listview xaml

<listview x:name="receiptlist" horizontalalignment="left" height="209.987" verticalalignment="top" width="645" margin="111,135.748,0,0" isenabled="false"  >     <listview.view>         <gridview>             <gridviewcolumn header="receiptid" width="60" displaymemberbinding="{binding receiptid}"/>             <gridviewcolumn header="itemno" width="50" displaymemberbinding="{binding itemno}"/>             <gridviewcolumn header="itemname" width="240" displaymemberbinding="{binding itemname}"/>             <gridviewcolumn header="packingsize" width="100" displaymemberbinding="{binding packingsize}"/>             <gridviewcolumn header="quantity"  width="50" displaymemberbinding="{binding quantity}"/>             <gridviewcolumn header="price"  width="50" displaymemberbinding="{binding price}"/>             <gridviewcolumn header="expirydate"  width="100" displaymemberbinding="{binding expirydate}"/>         </gridview>     </listview.view> </listview> 

now of button add rows in listview:

private void additems_click(object sender, routedeventargs e) {                  additems additems = new additems(hhk,2,"abc","36x63",3,opop,"22-11-2014");     receiptlist.items.add(additems); } 

additems class:

class additems {     public int receiptid { get; set; }     public int itemno { get; set; }      public string itemname { get; set; }     public string packingsize { get; set; }     public int quantity { get; set; }     public float price { get; set; }     public string expirydate { get; set; }      public additems()     {      }      public additems(int oid, int itno, string itname, string itsize, int qua, float pri, string edate)     {         this.receiptid = oid;         this.itemno = itno;         this.itemname = itname;         this.packingsize = itsize;         this.quantity = qua;         this.price = pri;         this.expirydate = edate;     } } 

now want add method counts how many items added in additems , want retrieve items additems of loop.

this not idea. i'll explain why:

1. user starts program , gets new order id based on current maximum order id in database
2. user b starts program , gets same order id nothing has been updated far.
3. both user , b save orders - , 2 different orders same id.

please, , users favour correctly start: either have database assign order id upon insert or create number-series table updates new order id whenever order id queried.

example:

table numberseries contain following fields:

seriesname        minid           maxid         currentvalue orders            1               999999        817 

the following stored procedure next possible order id safely!

create procedure spgetnextno     @seriesname begin     declare @newno table (value int)      update numberseries     set         currentvalue = currentvalue + 1     output inserted.currentvalue @newno              seriesname = @seriesname ,         currentvalue < maxid      select top 1 value @newno end 

you can use c# follows:

using (sqlcommand cmd = new sqlcommand("spgetnextno", conn)) {     cmd.commandtype = commandtype.storedprocedure;     cmd.parameters.addwithvalue("@seriesname", "orders");      object res = cmd.executescalar();     if (res == null || res == dbnull.value)         throw new invalidoperationexception("number series used up");      return (int)res; } 

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edit checked out habo's approach comments , following works, too:

create procedure spgetnextno     @seriesname begin     declare @newno int      update numberseries     set         @newno = currentvalue += 1              seriesname = @seriesname ,         currentvalue < maxid      select @newno end 

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edit asked in comments whether possible without using stored procedures. have not tried c#, i've entered following using test table in sql management studio , worked.

exec('declare @var int; update ttest set @var = test += 1; select @var;') 

this yields correct results in case. try execute above statement using sqlcommand this:

using (sqlcommand cmd = new sqlcommand("exec('declare @var int; update ttest set @var = test += 1; select @var;')", conn) {     object o = cmd.executescalar();     ... } 

of course use number series table suggested above , adjust query needed.

that worth trying. otoh, why don't want use stored procedures?