Object Reference Error while trying to put <hr> tag in stringBuilderObject.Append() VB.net

Question

My main aim is to underline some words in pdf with blue color using VB.net. The code is shown below:

strSignHTML.Append("<TD class=""TBLDATA"" width=""25%"" align=left><br /><br>")
strSignHTML.Append("<hr color=""midnightblue"">")
strSignHTML.Append("</TD>")
strSignHTML.Append("<td width=50%>&nbsp;</td>")
strSignHTML.Append("<td class=""TBLDATA"" width=""25%"" align=left> <br>")
strSignHTML.Append("<hr color=""midnightblue"">")
strSignHTML.Append("</td>")
strSignHTML.Append("</tr>")
strSignHTML.Append("<tr>")
strSignHTML.Append("<td class=""TBLDATA"">")
strSignHTML.Append("<font color=""midnightblue""><b>Signature</b></font>")
strSignHTML.Append("</td>")
strSignHTML.Append("<td width=50%>&nbsp;</td>")
strSignHTML.Append("<td class=""TBLDATA"">")
strSignHTML.Append("<font color=""midnightblue""><b>Date</b></font>")
strSignHTML.Append("</td>")
strSignHTML.Append("</tr>")
strSignHTML.Append("<tr>")

Answer 1

After you do import library

Imports System.Text

And actually set the strSignHTML as StringBuilder you are good to go

    Dim strSignHTML As New StringBuilder
    strSignHTML.Append("<TD class=""TBLDATA"" width=""25%"" align=left><br /><br>")
    strSignHTML.Append("<hr color=""midnightblue"">")
    strSignHTML.Append("</TD>")
    strSignHTML.Append("<td width=50%>&nbsp;</td>")
    strSignHTML.Append("<td class=""TBLDATA"" width=""25%"" align=left> <br>")
    strSignHTML.Append("<hr color=""midnightblue"">")
    strSignHTML.Append("</td>")
    strSignHTML.Append("</tr>")
    strSignHTML.Append("<tr>")
    strSignHTML.Append("<td class=""TBLDATA"">")
    strSignHTML.Append("<font color=""midnightblue""><b>Signature</b></font>")
    strSignHTML.Append("</td>")
    strSignHTML.Append("<td width=50%>&nbsp;</td>")
    strSignHTML.Append("<td class=""TBLDATA"">")
    strSignHTML.Append("<font color=""midnightblue""><b>Date</b></font>")
    strSignHTML.Append("</td>")
    strSignHTML.Append("</tr>")
    strSignHTML.Append("<tr>")

    Dim myString As String = strSignHTML.ToString

Even so i would rather use CDATA

Dim myString As String = <![CDATA[
                <TD class="TBLDATA" width="25%" align=left><br /><br>
                <hr color="midnightblue">
                </TD>
                <td width=50%>&nbsp;</td>
                <td class="TBLDATA" width="25%" align=left> <br>
                <hr color="midnightblue">
                </td>
                </tr>
                <tr>
                <td class="TBLDATA">
                <font color = "midnightblue"><b>Signature</b></font>
                </td>
                <td width = 50% >& nbsp;</td>
                <td class="TBLDATA">
                <font color = "midnightblue"><b>Date</b></font>
                </td>
                </tr>
                <tr>]]>.Value