How to export viewstate data to pdf in ASP.NET C#

Question

I am developing asp.net application and i already done from viewstate to excel (not from gridview to excel).

But, i am struggling to export pdf from viewstate.

my viewstate columns is nearly having 20 to 25 columns.

below is my code and correct me where i want to change the code.

also i am getting below error when i used itextsharp.

private void ExportToPDF()  
{  
  using (DataTable dt = (DataTable)ViewState["FinalData"])
            {
                Response.ContentType = "application/pdf";
                Response.AddHeader("content-disposition", "attachment;filename=Daily_Report.pdf");
                Response.Cache.SetCacheability(HttpCacheability.NoCache);
                StringWriter sw = new StringWriter();
                HtmlTextWriter hw = new HtmlTextWriter(sw);
                //dt.RenderControl(hw);
                StringReader sr = new StringReader(sw.ToString());
                Document pdfDoc = new Document(PageSize.A4, 10f, 10f, 10f, 0f);
                HTMLWorker htmlparser = new HTMLWorker(pdfDoc);
                PdfWriter.GetInstance(pdfDoc, Response.OutputStream);
                pdfDoc.Open();
                htmlparser.Parse(sr);
                pdfDoc.Close();
                Response.Write(pdfDoc);
                Response.End();
	   }
} 

Answer 1

Hi @Gani_tpt,

You can't "convert" a DataTable to a PDF Document. But you can insert data into it as normal content.

The specific code is as follows:

 public void ExportToPdf()
 {
     DataTable dt = (DataTable)ViewState["FinalData"];           
     MemoryStream mStream = new MemoryStream();
     Document document = new Document();
     PdfWriter writer = PdfWriter.GetInstance(document,  mStream);
     document.Open();
     PdfPTable pdfTable = new PdfPTable(dt.Columns.Count);
     pdfTable.WidthPercentage = 100;
     // Add table headers
     for (int i = 0; i < dt.Columns.Count; i++)
     {
         PdfPCell cell = new PdfPCell(new Phrase(dt.Columns[i].ColumnName));
         cell.BackgroundColor = BaseColor.LIGHT_GRAY;
         pdfTable.AddCell(cell);
     }
     // Add table rows
     for (int row = 0; row < dt.Rows.Count; row++)
     {
         for (int column = 0; column < dt.Columns.Count; column++)
         {
             pdfTable.AddCell(dt.Rows[row][column].ToString());
         }
     }
     document.Add(pdfTable);
     document.Close();
     Response.ContentType = "application/pdf";
     Response.AddHeader("content-disposition", "attachment;filename=GridViewExport.pdf");
     Response.Cache.SetCacheability(HttpCacheability.NoCache);
     Response.BinaryWrite(mStream.ToArray());
     Response.End();
 }

HTMLWorker is obsolete

This is not an error message, just a warning message.

Obsolete means it is not being used now. But still you can use it.

You can use XmlWorkerHelper class instead of HtmlWorker to convert HTML string to PDF.

Run the command below in the Package Manager Console.

Install-Package iTextSharp.xmlworker

But this method doesn't apply to your problem, I just add it here.

Best regards,
Lan Huang

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