function GetValueByKey(const AKey:string): string;


Description:


 Get the value by key. if no  do not match , it returns empty string.

Parameter:


  AKey: the key string  in the records.


Examples:


  ShowMessage('the first key name is: ' + UserData1.GetKeyByNo(0)+' Value: '+UserData1.GetValueByKey(UserData1.GetKeyByNo(0) ));