Step 3 of 4: Adding Code to the Control

In the last step, you added items to the first combo box. In this step, you will add code to the project that will populate the second combo box according to the option the user selects in the first combo box.

Select the first C1ComboBox control (“Category”).
In the Properties window, click the Events button.
Double-click the inside the SelectedIndexChanged text box to add the C1ComboBox1_SelectedIndexChanged event handler. The MainPage.xaml.cs page opens.
Import the following namespace into your project:

Visual Basic	Copy Code
Imports System.Collections.Generic

C#	Copy Code
using System.Collections.Generic;

Add the following code to the C1ComboBox1_SelectedIndexChanged event handler:

Visual Basic	Copy Code
'Create List for Comedy selection Dim dropDownList_Comedy As New List(Of String)() dropDownList_Comedy.Add("Absolutely Fabulous") dropDownList_Comedy.Add("The Colbert Report") dropDownList_Comedy.Add("The Daily Show") dropDownList_Comedy.Add("The Office") 'Create List for Drama selection Dim dropDownList_Drama As New List(Of String)() dropDownList_Drama.Add("Breaking Bad") dropDownList_Drama.Add("Desperate Housewives") dropDownList_Drama.Add("Mad Men") dropDownList_Drama.Add("The Sopranos") 'Create List for Science Fiction selection Dim dropDownList_SciFi As New List(Of String)() dropDownList_SciFi.Add("Battlestar Galactica") dropDownList_SciFi.Add("Caprica") dropDownList_SciFi.Add("Stargate") dropDownList_SciFi.Add("Star Trek") 'Check for SelectedIndex value and assign appropriate list to 2nd combo box If Category.SelectedIndex = 0 Then Shows.ItemsSource = dropDownList_Comedy ElseIf Category.SelectedIndex = 1 Then Shows.ItemsSource = dropDownList_Drama ElseIf Category.SelectedIndex = 2 Then Shows.ItemsSource = dropDownList_SciFi End If

Visual Basic

Copy Code

'Create List for Comedy selection
 Dim dropDownList_Comedy As New List(Of String)()
 dropDownList_Comedy.Add("Absolutely Fabulous")
 dropDownList_Comedy.Add("The Colbert Report")
 dropDownList_Comedy.Add("The Daily Show")
 dropDownList_Comedy.Add("The Office")
'Create List for Drama selection
 Dim dropDownList_Drama As New List(Of String)()
 dropDownList_Drama.Add("Breaking Bad")
 dropDownList_Drama.Add("Desperate Housewives")
 dropDownList_Drama.Add("Mad Men")
dropDownList_Drama.Add("The Sopranos")
'Create List for Science Fiction selection
 Dim dropDownList_SciFi As New List(Of String)()
 dropDownList_SciFi.Add("Battlestar Galactica")
 dropDownList_SciFi.Add("Caprica")
 dropDownList_SciFi.Add("Stargate")
 dropDownList_SciFi.Add("Star Trek")
'Check for SelectedIndex value and assign appropriate list to 2nd combo box
 If Category.SelectedIndex = 0 Then
    Shows.ItemsSource = dropDownList_Comedy
 ElseIf Category.SelectedIndex = 1 Then
    Shows.ItemsSource = dropDownList_Drama
 ElseIf Category.SelectedIndex = 2 Then
    Shows.ItemsSource = dropDownList_SciFi
 End If

C#	Copy Code
//Create List for Comedy selection List<string> dropDownList_Comedy = new List<string>(); dropDownList_Comedy.Add("Absolutely Fabulous"); dropDownList_Comedy.Add("The Colbert Report"); dropDownList_Comedy.Add("The Daily Show"); dropDownList_Comedy.Add("The Office"); //Create List for Drama selection List<string> dropDownList_Drama = new List<string>(); dropDownList_Drama.Add("Breaking Bad"); dropDownList_Drama.Add("Desperate Housewives"); dropDownList_Drama.Add("Mad Men"); dropDownList_Drama.Add("The Sopranos"); //Create List for Science Fiction selection List<string> dropDownList_SciFi = new List<string>(); dropDownList_SciFi.Add("Battlestar Galactica"); dropDownList_SciFi.Add("Caprica"); dropDownList_SciFi.Add("Stargate"); dropDownList_SciFi.Add("Star Trek"); //Check for SelectedIndex value and assign appropriate list to 2nd combo box if (Category.SelectedIndex == 0) { Shows.ItemsSource = dropDownList_Comedy; } else if (Category.SelectedIndex == 1) { Shows.ItemsSource = dropDownList_Drama; } else if (Category.SelectedIndex ==2) { Shows.ItemsSource = dropDownList_SciFi; }

Copy Code

//Create List for Comedy selection
 List<string> dropDownList_Comedy = new List<string>();
 dropDownList_Comedy.Add("Absolutely Fabulous");
 dropDownList_Comedy.Add("The Colbert Report");
 dropDownList_Comedy.Add("The Daily Show");
 dropDownList_Comedy.Add("The Office");              
//Create List for Drama selection
 List<string> dropDownList_Drama = new List<string>();
 dropDownList_Drama.Add("Breaking Bad");
 dropDownList_Drama.Add("Desperate Housewives");
 dropDownList_Drama.Add("Mad Men");
 dropDownList_Drama.Add("The Sopranos");              
//Create List for Science Fiction selection
 List<string> dropDownList_SciFi = new List<string>();
 dropDownList_SciFi.Add("Battlestar Galactica");
 dropDownList_SciFi.Add("Caprica");
 dropDownList_SciFi.Add("Stargate");
 dropDownList_SciFi.Add("Star Trek");                     
//Check for SelectedIndex value and assign appropriate list to 2nd combo box
 if (Category.SelectedIndex == 0)
 {
      Shows.ItemsSource = dropDownList_Comedy;
 }
 else if (Category.SelectedIndex == 1)
 {
      Shows.ItemsSource = dropDownList_Drama;
 }
 else if (Category.SelectedIndex ==2)
 {
      Shows.ItemsSource = dropDownList_SciFi;
 }

In the next step, you will run the project and observe the results of this quick start.