How to Bind Dropdown value based on another dropdown using vb .net

Question

Hi Team,

I have two dropdown List and second dropdown value will bind based on selecting first one . I am using vb net as language. So What approch I can follow as OnSelectedIndexChanged event we cannot use in vb. Please help if any.

Amit Mohanty · Answer

In VB.NET, you can use the SelectedIndexChanged event of the first dropdown list to dynamically populate the second dropdown list. First, create the two dropdown lists and the first dropdown list has the AutoPostBack property set to True and the OnSelectedIndexChanged event set to ddlDropDownList_SelectedIndexChanged . Then, in your code-behind file, add the following code: Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load If Not IsPostBack Then 'Populate the second dropdown list with the default values based on the first dropdown list' PopulateSecondDropDownList(ddlDropDownList.SelectedValue) End If End Sub Protected Sub ddlDropDownList_SelectedIndexChanged(ByVal sender As Object, ByVal e As EventArgs) 'Populate the second dropdown list based on the selected value of the first dropdown list' PopulateSecondDropDownList(ddlDropDownList.SelectedValue) End Sub Private Sub PopulateSecondDropDownList(ByVal selectedValue As String) 'Clear the items in the second dropdown list' ddlDropDownList2.Items.Clear() 'Populate the items in the second dropdown list based on the selected value of the first dropdown list' Select Case selectedValue Case "1" ddlDropDownList2.Items.Add(New ListItem("Option 1.1", "1.1")) ddlDropDownList2.Items.Add(New ListItem("Option 1.2", "1.2")) ddlDropDownList2.Items.Add(New ListItem("Option 1.3", "1.3")) Case "2" ddlDropDownList2.Items.Add(New ListItem("Option 2.1", "2.1")) ddlDropDownList2.Items.Add(New ListItem("Option 2.2", "2.2")) ddlDropDownList2.Items.Add(New ListItem("Option 2.3", "2.3")) Case "3" ddlDropDownList2.Items.Add(New ListItem("Option 3.1", "3.1")) ddlDropDownList2.Items.Add(New ListItem("Option 3.2", "3.2")) ddlDropDownList2.Items.Add(New ListItem("Option 3.3", "3.3")) End Select End Sub

Rajkiran Swain · Answer

function BindSecondDropdown(selectedValue) { $.ajax({ type: "POST", url: "PageName.aspx/PopulateSecondDropdown", data: '{selectedValue: "' + selectedValue + '" }', contentType: "application/json; charset=utf-8", dataType: "json", success: function (response) { var ddlSecond = document.getElementById(' '); ddlSecond.innerHTML = ""; for (var i = 0; i Protected Sub ddlFirst_SelectedIndexChanged(ByVal sender As Object, ByVal e As EventArgs) Handles ddlFirst.SelectedIndexChanged ' Clear the items of the second dropdown list ddlSecond.Items.Clear() ' Get the selected value of the first dropdown list Dim selectedValue As String = ddlFirst.SelectedValue ' Bind the items of the second dropdown list based on the selected value of the first dropdown list If selectedValue = "Option 1" Then ddlSecond.Items.Add(New ListItem("Option A", "1")) ddlSecond.Items.Add(New ListItem("Option B", "2")) ElseIf selectedValue = "Option 2" Then ddlSecond.Items.Add(New ListItem("Option C", "3")) ddlSecond.Items.Add(New ListItem("Option D", "4")) End If End Sub

Rajeesh Menoth · Answer

Hi, Go through the following article for VB - https://www.aspsnippets.com/Articles/Populate-Cascading-DropDownList-from-Database-in-ASPNet-Example.aspx