c# - Unable to create complex property of custom control -

i trying create on multi value complex propety of custom control written code not working, multi value read property coming in property explorer. here code it

private mycomboproperties _mycomboproperties;  public mycomboproperties mycombopropertiesvalues {         {         return _mycomboproperties;     }     set     {         _mycomboproperties = value;     } }  //mycomboproperties struct  [system.runtime.interopservices.comvisible(true)] public struct mycomboproperties {     private string _mysourcequery;     private string _mydisplaymember;     private string _myvaluemember;      public mycomboproperties(string mysourcequery, string mydisplaymember, string myvaluemember)     {         _mysourcequery = mysourcequery;         _mydisplaymember = mydisplaymember;         _myvaluemember = myvaluemember;     }      public string mysourcequery     {                 {             return _mysourcequery;         }         set         {             _mysourcequery = value;         }     }      public string mydisplaymember     {                 {             return _mydisplaymember;         }         set         {             _mydisplaymember = value;         }     }      public string myvaluemember     {                  {             return _myvaluemember;         }         set         {             _myvaluemember = value;         }     } } 

or else provide me sample code multi value custom control 3 input string value.

use below code achieve objective.

using system; using system.collections.generic; using system.componentmodel; using system.diagnostics; using system.linq; using system.text; using system.drawing; using system.globalization;  namespace expandablemultivaluedcustomcontrol { public partial class mycombobox : system.windows.forms.combobox {     private mycomboproperties _comboproperties = new mycomboproperties();     public mycombobox()     {         initializecomponent();     }      public mycombobox(icontainer container)     {         container.add(this);          initializecomponent();     }      [category("my combo properties")]     [displayname("my combo properties")]     [description("my combo properties")]     [designerserializationvisibility(designerserializationvisibility.content)]     public mycomboproperties mycomboproperties     {                 {             return _comboproperties;         }         set         {             _comboproperties = value;         }     } }  [displayname("my combo properties")] [description("cmy combo properties")] [defaultproperty("text")] [designercategory("component")] [typeconverter(typeof(expandableobjectconverter))]  public class mycomboproperties {     private string _mysourcequery;     private string _mydisplaymember;     private string _myvaluemember;     public mycomboproperties()     {      }      [category("mycomboboxproperties")]     [displayname("mysourcequery")]     [description("mysourcequery")]     public string mysourcequery     {                 {             return _mysourcequery;         }         set         {             _mysourcequery = value;         }     }      [category("mycomboboxproperties")]     [displayname("mydisplaymember")]     [description("mydisplaymember")]     public string mydisplaymember     {                 {             return _mydisplaymember;         }         set         {             _mydisplaymember = value;         }     }      [category("mycomboboxproperties")]     [displayname("myvaluemember")]     [description("myvaluemember")]     public string myvaluemember     {                 {             return _myvaluemember;         }         set         {             _myvaluemember = value;         }     }     } } 

and access properties have access this:

mycombobox1.mycomboproperties.mydisplaymember  mycombobox1.mycomboproperties.myvaluemember  mycombobox1.mycomboproperties.mysourcequery