In this article I will explain solution to the following error (exception) when we use HtmlWorker to convert HTML string to PDF using iTextSharp PDF conversion library.
Unable to cast object of type 'iTextSharp.text.html.simpleparser.CellWrapper' to type 'iTextSharp.text.Paragraph'.
One of my readers reported me the above error when exporting ASP.Net GridView to PDF when he used the latest version of iTextSharp DLL instead of the one provided in the article sample.
 
Solution
Though the same article sample worked for me with new as well as the older version of iTextSharp, I recommended him to use XmlWorkerHelper class instead of HtmlWorker for converting HTML string to PDF and that worked for him.
Thus further I am explaining how to use XmlWorkerHelper class instead of HtmlWorker when exporting ASP.Net GridView to PDF.
 
Download XmlWorkerHelper DLL
You can download the XmlWorkerHelper DLL from the following link.
Download XmlWorkerHelper DLL
Once downloaded you need to place the XmlWorkerHelper DLL in the BIN folder and add its reference to the project.
 
HTML Markup
The following HTML Markup consists of an ASP.Net GridView and a Button.
<asp:GridView ID="GridView1" HeaderStyle-BackColor="#666666" HeaderStyle-ForeColor="White"
    RowStyle-BackColor="#E4E4E4" runat="server" AutoGenerateColumns="false">
    <Columns>
        <asp:BoundField DataField="Id" HeaderText="Customer Id" ItemStyle-Width="100px" />
        <asp:BoundField DataField="Name" HeaderText="Name" ItemStyle-Width="120px" />
        <asp:BoundField DataField="Country" HeaderText="Country" ItemStyle-Width="120px" />
    </Columns>
</asp:GridView>
<br />
<asp:Button ID="btnExport" runat="server" Text="Export To PDF" OnClick="ExportToPDF" />
 
 
Namespaces
You will need to import the following namespaces.
C#
using System.IO;
using System.Data;
using iTextSharp.text;
using iTextSharp.text.html.simpleparser;
using iTextSharp.text.pdf;
using iTextSharp.tool.xml;
 
VB.Net
Imports System.IO
Imports System.Data
Imports iTextSharp.text
Imports iTextSharp.text.html.simpleparser
Imports iTextSharp.text.pdf
Imports iTextSharp.tool.xml
 
 
Binding the ASP.Net GridView control
I have created a dynamic DataTable with some dummy data and it is used to populate the GridView control in the Page Load event.
Note: You can learn more about this dynamic DataTable in my article Create DataTable dynamically and bind to GridView in ASP.Net.
C#
protected void Page_Load(object sender, EventArgs e)
{
    if (!this.IsPostBack)
    {
        DataTable dt = new DataTable();
        dt.Columns.AddRange(new DataColumn[3] { new DataColumn("Id"), new DataColumn("Name"), new DataColumn("Country") });
        dt.Rows.Add(1, "John Hammond", "United States");
        dt.Rows.Add(2, "Mudassar Khan", "India");
        dt.Rows.Add(3, "Suzanne Mathews", "France");
        dt.Rows.Add(4, "Robert Schidner", "Russia");
        GridView1.DataSource = dt;
        GridView1.DataBind();
    }
}
 
VB.Net
Protected Sub Page_Load(sender As Object, e As EventArgs) Handles Me.Load
    If Not Me.IsPostBack Then
        Dim dt As New DataTable()
        dt.Columns.AddRange(New DataColumn(2) {New DataColumn("Id"), New DataColumn("Name"), New DataColumn("Country")})
        dt.Rows.Add(1, "John Hammond", "United States")
        dt.Rows.Add(2, "Mudassar Khan", "India")
        dt.Rows.Add(3, "Suzanne Mathews", "France")
        dt.Rows.Add(4, "Robert Schidner", "Russia")
        GridView1.DataSource = dt
        GridView1.DataBind()
    End If
End Sub
 
 
Exporting GridView to PDF using XmlWorkerHelper class
When the export button is clicked, the GridView is rendered into an HTML string using HtmlTextWriter class.
The generated HTML is then converted to PDF using XmlWorkerHelper class and finally the PDF is sent to the Response Stream for download.
C#
protected void ExportToPDF(object sender, EventArgs e)
{
    using (StringWriter sw = new StringWriter())
    {
        using (HtmlTextWriter hw = new HtmlTextWriter(sw))
        {
            GridView1.RenderControl(hw);
            StringReader sr = new StringReader(sw.ToString());
            Document pdfDoc = new Document(PageSize.A4, 10f, 10f, 10f, 0f);
            PdfWriter writer = PdfWriter.GetInstance(pdfDoc, Response.OutputStream);
            pdfDoc.Open();
            XMLWorkerHelper.GetInstance().ParseXHtml(writer, pdfDoc, sr);
            pdfDoc.Close();
            Response.ContentType = "application/pdf";
            Response.AddHeader("content-disposition", "attachment;filename=GridViewExport.pdf");
            Response.Cache.SetCacheability(HttpCacheability.NoCache);
            Response.Write(pdfDoc);
            Response.End();
        }
    }
}
 
public override void VerifyRenderingInServerForm(Control control)
{
    /* Verifies that the control is rendered */
}
 
VB.Net
Protected Sub ExportToPDF(sender As Object, e As EventArgs)
    Using sw As New StringWriter()
        Using hw As New HtmlTextWriter(sw)
            GridView1.RenderControl(hw)
            Dim sr As New StringReader(sw.ToString())
            Dim pdfDoc As New Document(PageSize.A4, 10.0F, 10.0F, 10.0F, 0.0F)
            Dim writer As PdfWriter = PdfWriter.GetInstance(pdfDoc, Response.OutputStream)
            pdfDoc.Open()
            XMLWorkerHelper.GetInstance().ParseXHtml(writer, pdfDoc, sr)
            pdfDoc.Close()
            Response.ContentType = "application/pdf"
            Response.AddHeader("content-disposition", "attachment;filename=GridViewExport.pdf")
            Response.Cache.SetCacheability(HttpCacheability.NoCache)
            Response.Write(pdfDoc)
            Response.End()
        End Using
    End Using
End Sub
 
Public Overrides Sub VerifyRenderingInServerForm(control As Control)
    ' Verifies that the control is rendered
End Sub
 
 
Screenshot
Unable to cast object of type 'iTextSharp.text.html.simpleparser.CellWrapper' to type 'iTextSharp.text.Paragraph'
 
 
Demo
View Demo
 
 
Downloads
Download Code