c# - Calling (ID_number) primary key to textbox using Combobox(Category Description) -

dealing foreign key using ms access in c#.

each time select category description(catdesc) using combobox category table, wanted get/call automatically category id(catid) in textbox1.

my code doesn't worked, , no errors given.

this sample_code:

private void cmdcategoryy_textchanged(object sender, eventargs e) {        categorydesc();     }  void categorydesc()  {     oledbconnection mycon = new oledbconnection(@"provider = microsoft.ace.oledb.12.0; data source = c:\users\blabla\desktop\docsmonitorg\try 081517\windowsformsapp6\windowsformsapp6\database.accdb");      string con;      try     {          con = "select catid, catdesc category catdesc = '" + cmdcategoryy.text + "' ";         mycon.open();         oledbcommand cm = new oledbcommand();         oledbdataadapter da = new oledbdataadapter();         datatable mydata1 = new datatable();          cm.commandtext = con;         cm.connection = mycon;          int i;         da.selectcommand = cm;         da.fill(mydata1);          (i = 0; <= mydata1.rows.count - 1;)             textbox1.text = (mydata1.rows[i]["catid"].tostring());      }      catch (exception ex)     {         messagebox.show(ex.message, "message", messageboxbuttons.ok, messageboxicon.error);      }          {         mycon.close();         mycon.dispose();     }   } 

here design

this database sample:

category description has graphic desginer, autocat, ax staff category id 1,2,3

i hide textbox1. , godbless!.

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