Cascading Dropdown List for Country/State/City in ASP.Net

Cascading Dropdown List for Country/State/City in ASP.Net

I am going to show how we can work with cascading dropdown list for country/state/city in asp.net 

Create three tables as per our need

CREATE TABLE country

  (

     countryID     INT NOT NULL,

     countryName   varchar(50) NOT NULL,

     PRIMARY KEY (countryID ),

  );

CREATE TABLE state

  (

 stateID     INT NOT NULL,

 countryID INT NOTNULL,

 stateName   varchar(50) NOT NULL,

 PRIMARY KEY (stateID ),

 FOREIGN KEY (countryID ) REFERENCES country (countryID));

CREATE TABLE city

  (

cityID     INT NOT NULL,

 stateID INT NOTNULL,

 cityName   varchar(50) NOT NULL,

 PRIMARY KEY (cityID),

 FOREIGN KEY (stateID) REFERENCES state (stateID));