Regular Expression to validate 14 digit number using C# and VB.Net in ASP.Net

Hi chetan,

Check this example. Now please take its reference and correct your code.

HTML

<asp:TextBox runat="server" ID="txtValue" />
<asp:Button Text="Validate" runat="server" OnClick="ValidateText" />

C#

protected void ValidateText(object sender, EventArgs e)
{
    System.Text.RegularExpressions.Regex regex = new System.Text.RegularExpressions.Regex("^[0-9]{14}$");
    if (regex.IsMatch(txtValue.Text.Trim()))
    {
        ClientScript.RegisterClientScriptBlock(this.GetType(), "", "alert('Valid')", true);
    }
    else
    {
        ClientScript.RegisterClientScriptBlock(this.GetType(), "", "alert('Invalid')", true);
    }
}

VB.Net

Protected Sub ValidateText(ByVal sender As Object, ByVal e As EventArgs)
    Dim regex As System.Text.RegularExpressions.Regex = New System.Text.RegularExpressions.Regex("^[0-9]{14}$")
    If regex.IsMatch(txtValue.Text.Trim()) Then
        ClientScript.RegisterClientScriptBlock(Me.[GetType](), "", "alert('Valid')", True)
    Else
        ClientScript.RegisterClientScriptBlock(Me.[GetType](), "", "alert('Invalid')", True)
    End If
End Sub

Screenshot