ComboBox Events And Dynamic Data Binding in WPF - Part - 13

XML To Create the Comboboxes

<Canvas>

        <StackPanel Orientation="Horizontal" Height="50" Canvas.Left="130" Canvas.Top="118">

            <TextBlock Margin="0,0,20,0">Country</TextBlock>

            <ComboBox Name="cmbCountry" Width="200" Height="30" SelectionChanged="cmbCountry_SelectionChanged"

                      VerticalAlignment="Top" DisplayMemberPath="Name" SelectedValuePath="Id" SelectedValue="{Binding Id}">

            </ComboBox>

        </StackPanel>

        <StackPanel Orientation="Horizontal" Height="50" Canvas.Left="130" Canvas.Top="212">

            <TextBlock Margin="0,0,30,0">State</TextBlock>

            <ComboBox Name="cmbStates" Width="200" Height="30" VerticalAlignment="Top" DisplayMemberPath="Name" SelectedValuePath="Id">

            </ComboBox>

        </StackPanel>

    </Canvas>

Methods to fetch the data from MSSQL using Entity Framework

 void FillCountries()

        {

            WpfTutorialsEntities obj = new WpfTutorialsEntities();

            List<Country> lst = obj.Countries.ToList();

            cmbCountry.ItemsSource = lst;

        }

        private void cmbCountry_SelectionChanged(object sender, SelectionChangedEventArgs e)

        {

            int CountryId = Convert.ToInt32(cmbCountry.SelectedValue);

            WpfTutorialsEntities obj = new WpfTutorialsEntities();

            List<State> lst = obj.States.Where(x => x.CountryId == CountryId).ToList();

            cmbStates.ItemsSource = lst;

        }

MSSQL Script To Create the Tables and Insert the Data

USE [WpfTutorials]

GO

/****** Object:  Table [dbo].[Countries]    Script Date: 11/05/2016 23:13:59 ******/

SET ANSI_NULLS ON

GO

SET QUOTED_IDENTIFIER ON

GO

SET ANSI_PADDING ON

GO

CREATE TABLE [dbo].[Countries](

[Id] [int] IDENTITY(1,1) NOT NULL,

[Name] [varchar](256) NOT NULL,

PRIMARY KEY CLUSTERED 

(

[Id] ASC

)WITH (PAD_INDEX  = OFF, STATISTICS_NORECOMPUTE  = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS  = ON, ALLOW_PAGE_LOCKS  = ON) ON [PRIMARY]

) ON [PRIMARY]

GO

SET ANSI_PADDING OFF

GO

SET IDENTITY_INSERT [dbo].[Countries] ON

INSERT [dbo].[Countries] ([Id], [Name]) VALUES (1, N'USA')

INSERT [dbo].[Countries] ([Id], [Name]) VALUES (2, N'UK')

INSERT [dbo].[Countries] ([Id], [Name]) VALUES (3, N'India')

SET IDENTITY_INSERT [dbo].[Countries] OFF

/****** Object:  Table [dbo].[States]    Script Date: 11/05/2016 23:13:59 ******/

SET ANSI_NULLS ON

GO

SET QUOTED_IDENTIFIER ON

GO

SET ANSI_PADDING ON

GO

CREATE TABLE [dbo].[States](

[Id] [int] IDENTITY(1,1) NOT NULL,

[CountryId] [int] NOT NULL,

[Name] [varchar](256) NOT NULL,

PRIMARY KEY CLUSTERED 

(

[Id] ASC

)WITH (PAD_INDEX  = OFF, STATISTICS_NORECOMPUTE  = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS  = ON, ALLOW_PAGE_LOCKS  = ON) ON [PRIMARY]

) ON [PRIMARY]

GO

SET ANSI_PADDING OFF

GO

SET IDENTITY_INSERT [dbo].[States] ON

INSERT [dbo].[States] ([Id], [CountryId], [Name]) VALUES (1, 1, N'Alabama')

INSERT [dbo].[States] ([Id], [CountryId], [Name]) VALUES (2, 1, N'Alaska')

INSERT [dbo].[States] ([Id], [CountryId], [Name]) VALUES (3, 2, N'Lancashire')

INSERT [dbo].[States] ([Id], [CountryId], [Name]) VALUES (4, 2, N'London')

INSERT [dbo].[States] ([Id], [CountryId], [Name]) VALUES (5, 3, N'Goa')

INSERT [dbo].[States] ([Id], [CountryId], [Name]) VALUES (6, 3, N'Delhi')

INSERT [dbo].[States] ([Id], [CountryId], [Name]) VALUES (7, 3, N'Rajasthan')

INSERT [dbo].[States] ([Id], [CountryId], [Name]) VALUES (8, 3, N'Gujrat')

SET IDENTITY_INSERT [dbo].[States] OFF

/****** Object:  ForeignKey [FK__States__Name__0519C6AF]    Script Date: 11/05/2016 23:13:59 ******/

ALTER TABLE [dbo].[States]  WITH CHECK ADD FOREIGN KEY([CountryId])

REFERENCES [dbo].[Countries] ([Id])

GO

Note : To create the Entity Data Model please watch the Video Tutorial. It will guide you step by step to create the EDMX file.