Create dynamic TextBox for exam quiz option using C# and VB.Net in ASP.Net

Hi irshad1231,

Refer below sample and change the saving code as per your database structure.

HTML

<table border="0" cellpadding="0" cellspacing="0">
    <tr>
        <td>Question:</td>
        <td><asp:TextBox runat="server" ID="txtQuestion" /></td>
    </tr>
    <tr>
        <td>No Of Option:</td>
        <td><asp:TextBox runat="server" ID="txtOptions" AutoPostBack="true" OnTextChanged="GenerateOption" /></td>
    </tr>
    <tr>
        <td colspan="2">
            <asp:Panel ID="pnlOptions" runat="server" Visible="false">
            </asp:Panel>
        </td>
    </tr>
    <tr>
        <td>Answer:</td>
        <td><asp:TextBox runat="server" ID="txtAnswer" /></td>
    </tr>
    <tr>
        <td colspan="2" align="center">
            <asp:Button Text="Save" runat="server" OnClick="Save" />
        </td>
    </tr>
</table>

Namespaces

C#

using System.Configuration;
using System.Data.SqlClient;

VB.Net

Imports System.Configuration
Imports System.Data.SqlClient

Code

C#

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);
        i++;
    }
}
protected void GenerateOption(object sender, EventArgs e)
{
    pnlOptions.Controls.Clear();
    int index = pnlOptions.Controls.OfType<TextBox>().ToList().Count + 1;
    for (int i = 0; i < Convert.ToInt32(txtOptions.Text); i++)
    {
        this.CreateTextBox("txtDynamic" + (index + i));
    }
    pnlOptions.Visible = true;
}
protected void Save(object sender, EventArgs e)
{
    string question = txtQuestion.Text.Trim();
    string answer = txtAnswer.Text.Trim();
    string query = "INSERT INTO QuizAnswer (Question,Answer,";
    for (int i = 1; i <= Convert.ToInt32(txtOptions.Text); i++)
    {
        query += "Option" + i + ",";
    }
    query = query.Remove(query.Length - 1, 1);
    query += ") VALUES(@Question,@Answer,";

    for (int i = 1; i <= Convert.ToInt32(txtOptions.Text); i++)
    {
        query += "@Option" + i + ",";
    }
    query = query.Remove(query.Length - 1, 1) + ")";

    string constr = ConfigurationManager.ConnectionStrings["constr"].ConnectionString;
    using (SqlConnection con = new SqlConnection(constr))
    {
        using (SqlCommand cmd = new SqlCommand(query))
        {
            cmd.Parameters.AddWithValue("@Question", question);
            cmd.Parameters.AddWithValue("@Answer", answer);
            int i = 1;
            foreach (TextBox textBox in pnlOptions.Controls.OfType<TextBox>())
            {
                cmd.Parameters.AddWithValue("@Option" + 1, textBox.Text);
                i++;
            }
            cmd.Connection = con;
            con.Open();
            cmd.ExecuteNonQuery();
            con.Close();
        }
    }
}
private void CreateTextBox(string id)
{
    Label lbl = new Label();
    lbl.Text = "Option " + id.Replace("txtDynamic", "") + ": ";
    pnlOptions.Controls.Add(lbl);

    Literal lt = new Literal();
    lt.Text = "&nbsp;&nbsp;";
    pnlOptions.Controls.Add(lt);

    TextBox txt = new TextBox();
    txt.ID = id;
    pnlOptions.Controls.Add(txt);

    lt = new Literal();
    lt.Text = "<br />";
    pnlOptions.Controls.Add(lt);
}

VB.Net

Protected Sub Page_PreInit(ByVal sender As Object, ByVal 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
    Next
End Sub

Protected Sub GenerateOption(ByVal sender As Object, ByVal e As EventArgs)
    pnlOptions.Controls.Clear()
    Dim index As Integer = pnlOptions.Controls.OfType(Of TextBox)().ToList().Count + 1
    For i As Integer = 0 To Convert.ToInt32(txtOptions.Text) - 1
        Me.CreateTextBox("txtDynamic" & (index + i))
    Next
    pnlOptions.Visible = True
End Sub

Protected Sub Save(ByVal sender As Object, ByVal e As EventArgs)
    Dim question As String = txtQuestion.Text.Trim()
    Dim answer As String = txtAnswer.Text.Trim()
    Dim query As String = "INSERT INTO QuizAnswer (Question,Answer,"
    For i As Integer = 1 To Convert.ToInt32(txtOptions.Text)
        query += "Option" & i & ","
    Next
    query = query.Remove(query.Length - 1, 1)
    query += ") VALUES(@Question,@Answer,"
    For i As Integer = 1 To Convert.ToInt32(txtOptions.Text)
        query += "@Option" & i & ","
    Next
    query = query.Remove(query.Length - 1, 1) & ")"
    Dim constr As String = ConfigurationManager.ConnectionStrings("constr").ConnectionString
    Using con As SqlConnection = New SqlConnection(constr)
        Using cmd As SqlCommand = New SqlCommand(query)
            cmd.Parameters.AddWithValue("@Question", question)
            cmd.Parameters.AddWithValue("@Answer", answer)
            Dim i As Integer = 1
            For Each textBox As TextBox In pnlOptions.Controls.OfType(Of TextBox)()
                cmd.Parameters.AddWithValue("@Option" & 1, textBox.Text)
                i += 1
            Next
            cmd.Connection = con
            con.Open()
            cmd.ExecuteNonQuery()
            con.Close()
        End Using
    End Using
End Sub

Private Sub CreateTextBox(ByVal id As String)
    Dim lbl As Label = New Label()
    lbl.Text = "Option " & id.Replace("txtDynamic", "") & ": "
    pnlOptions.Controls.Add(lbl)

    Dim lt As Literal = New Literal()
    lt.Text = "  "
    pnlOptions.Controls.Add(lt)

    Dim txt As TextBox = New TextBox()
    txt.ID = id
    pnlOptions.Controls.Add(txt)

    lt = New Literal()
    lt.Text = "<br />"
    pnlOptions.Controls.Add(lt)
End Sub