In this article I will explain with an example, how to create controls dynamically and retrieve values from it in ASP.Net using C# and VB.Net.
This article will illustrate how to create dynamic TextBox controls and retrieve values on PostBack in ASP.Net using C# and VB.Net.
HTML Markup
The HTML Markup consists of an ASP.Net Panel control and two Buttons, one for adding TextBoxes and other one for getting the values of the dynamically generated TextBoxes.
<asp:Panel ID="pnlTextBoxes" runat="server">
<hr />
<asp:Button ID="btnAdd" runat="server" Text="Add New" OnClick="AddTextBox" />
<asp:Button ID="btnGet" runat="server" Text="Get Values" OnClick="GetTextBoxValues" />
Creating controls dynamically and retrieving values from it in ASP.Net
When the Add Button is clicked, first the count of all the TextBoxes present in the Panel control is determined and then it is incremented to generate an Index which will be used for generating a unique ID for the TextBox control.
The unique ID is passed to the CreateTextBox method, which creates a dynamic TextBox and appends it to the Panel control.
Note: It is very important to give a common prefix (example txtDynamic) for all TextBoxes as it will be used to find and recreate all dynamic TextBoxes on PostBack.
protected void AddTextBox(object sender, EventArgs e)
    int index = pnlTextBoxes.Controls.OfType<TextBox>().ToList().Count + 1;
    this.CreateTextBox("txtDynamic" + index);
private void CreateTextBox(string id)
    TextBox txt = new TextBox();
    txt.ID = id;
    Literal lt = new Literal();
    lt.Text = "<br />";
Protected Sub AddTextBox(sender As Object, e As EventArgs)
    Dim index As Integer = pnlTextBoxes.Controls.OfType(Of TextBox)().ToList().Count + 1
    Me.CreateTextBox("txtDynamic" & index)
End Sub
Private Sub CreateTextBox(id As String)
    Dim txt As New TextBox()
    txt.ID = id
    Dim lt As New Literal()
    lt.Text = "<br />"
End Sub
Retaining the dynamic controls on PostBack
In order to retain the dynamic TextBoxes across PostBacks, we need to make use of Page’s PreInit event to recreate the dynamic TextBoxes using the Request.Form collection.
First all the keys containing the string txtDynamic are fetched and then for each key the CreateTextBox method is called.
protected void Page_PreInit(object sender, EventArgs e)
    List<string> keys = Request.Form.AllKeys.Where(key => key.Contains("txtDynamic")).ToList();
    int i = 1;
    foreach (string key in keys)
        this.CreateTextBox("txtDynamic" + i);
Protected Sub Page_PreInit(sender As Object, e As EventArgs) Handles Me.PreInit
    Dim keys As List(Of String) = Request.Form.AllKeys.Where(Function(key) key.Contains("txtDynamic")).ToList()
    Dim i As Integer = 1
    For Each key As String In keys
        Me.CreateTextBox("txtDynamic" & i)
        i += 1
End Sub
Retrieving values of dynamically created controls
When the Get Button is clicked, a loop is executed over all the TextBoxes present inside the Panel control. Inside the loop, the ID and the Value of each TextBox is fetched and displayed using JavaScript Alert message box.
protected void GetTextBoxValues(object sender, EventArgs e)
    string message = "";
    foreach (TextBox textBox in pnlTextBoxes.Controls.OfType<TextBox>())
        message += textBox.ID + ": " + textBox.Text + "\\n";
    ClientScript.RegisterClientScriptBlock(this.GetType(), "alert", "alert('" + message + "');", true);
Protected Sub GetTextBoxValues(sender As Object, e As EventArgs)
    Dim message As String = ""
    For Each textBox As TextBox In pnlTextBoxes.Controls.OfType(Of TextBox)()
        message += textBox.ID + ": " + textBox.Text + "\n"
    ClientScript.RegisterClientScriptBlock(Me.GetType(), "alert", "alert('" & message & "');", True)
End Sub
Create controls dynamically and retrieve values from it in ASP.Net using C# and VB.Net