Extract only Numeric data from AlphaNumeric data using C# and VB.Net in ASP.Net

Hi rajeesh,

Refer below sample.

HTML

Question No :
<asp:TextBox runat="server" ID="txtQuestioNo" OnTextChanged="Save" AutoPostBack="true" />
<br />
<asp:Label ID="lblNumber" runat="server" />

Namespaces

C#

using System.Text.RegularExpressions;

VB.Net

Imports System.Text.RegularExpressions

Code

C#

protected void Save(object sender, EventArgs e)
{
    string number = Regex.Replace(txtQuestioNo.Text, "[^0-9]+", string.Empty);
    ScriptManager.RegisterStartupScript(this, this.GetType(), "Message", "alert('" + number + "');", true);
}

VB.Net

Protected Sub Save(ByVal sender As Object, ByVal e As EventArgs)
    Dim number As String = Regex.Replace(txtQuestioNo.Text, "[^0-9]+", String.Empty)
    ScriptManager.RegisterStartupScript(Me, Me.GetType(), "Message", "alert('" & number & "');", True)
End Sub

Screenshot