Export to PDF in Sharepoint Custom web part

Question

I want to export my page to pdf in sharepoint custm web part. I am using below code to export to pdf. when i click the export button i am getting below Error. how to resolve this error? pLease help me.

Code

protected void ExporttoPDF_Click(object sender, EventArgs e)
{
        Response.ContentType = "application/pdf";
        Response.AddHeader("content-disposition", "attachment;filename=ExporttoPDF.pdf");
        Response.Cache.SetCacheability(HttpCacheability.NoCache);
        StringWriter sw = new StringWriter();
        HtmlTextWriter hw = new HtmlTextWriter(sw);
        this.Page.RenderControl(hw);
        StringReader sr = new StringReader(sw.ToString());
        Document pdfDoc = new Document(PageSize.A4, 10f, 10f, 100f, 0f);
        HTMLWorker htmlparser = new HTMLWorker(pdfDoc);
        PdfWriter.GetInstance(pdfDoc, Response.OutputStream);
        pdfDoc.Open();
        htmlparser.Parse(sr);
        pdfDoc.Close();
        Response.Write(pdfDoc);
        Response.End();
}

Error

Server Error in '/' Application. RegisterForEventValidation can only be called during Render(); Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code.

Exception Details: System.InvalidOperationException: 
RegisterForEventValidation can only be called during Render();

Source Error:

An unhandled exception was generated during the execution of the current web request. Information regarding the origin and location of the exception can be identified using the exception stack trace below.

Stack Trace:

[InvalidOperationException: RegisterForEventValidation can only be called during Render();]
   System.Web.UI.ClientScriptManager.RegisterForEventValidation(String uniqueId, String argument) +11081278
   System.Web.UI.WebControls.TextBox.AddAttributesToRender(HtmlTextWriter writer) +455
   System.Web.UI.WebControls.WebControl.RenderBeginTag(HtmlTextWriter writer) +27
   System.Web.UI.WebControls.TextBox.Render(HtmlTextWriter writer) +27
   System.Web.UI.Control.RenderChildrenInternal(HtmlTextWriter writer, ICollection children) +240
   System.Web.UI.HtmlControls.HtmlContainerControl.Render(HtmlTextWriter writer) +42
   System.Web.UI.Control.RenderChildrenInternal(HtmlTextWriter writer, ICollection children) +240
   System.Web.UI.Control.RenderChildrenInternal(HtmlTextWriter writer, ICollection children) +240
   System.Web.UI.HtmlControls.HtmlForm.RenderChildren(HtmlTextWriter writer) +411
   System.Web.UI.HtmlControls.HtmlForm.Render(HtmlTextWriter output) +87
   System.Web.UI.HtmlControls.HtmlForm.RenderControl(HtmlTextWriter writer) +53
   System.Web.UI.Control.RenderChildrenInternal(HtmlTextWriter writer, ICollection children) +240
   System.Web.UI.HtmlControls.HtmlContainerControl.Render(HtmlTextWriter writer) +42
   System.Web.UI.Control.RenderChildrenInternal(HtmlTextWriter writer, ICollection children) +240
   System.Web.UI.Control.RenderChildrenInternal(HtmlTextWriter writer, ICollection children) +240
   System.Web.UI.Page.Render(HtmlTextWriter writer) +38
   Microsoft.SharePoint.WebPartPages.WikiEditPage.Render(HtmlTextWriter writer) +207
   PayrollProject.PaySlip4Employee.PaySlip4EmployeeUserControl.btnPDF_Click(Object sender, EventArgs e) +425
   System.Web.UI.WebControls.Button.OnClick(EventArgs e) +115
   System.Web.UI.WebControls.Button.RaisePostBackEvent(String eventArgument) +140
   System.Web.UI.Page.RaisePostBackEvent(IPostBackEventHandler sourceControl, String eventArgument) +29
   System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +2981

Version Information: Microsoft .NET Framework Version:2.0.50727.5472; ASP.NET Version:2.0.50727.5474

Nagaraj S Nagaraj S · Accepted Answer · 2014-02-10T09:54:02

Add this in @Page Directive

EnableEventValidation ="false"

Like

<%@ Page Language="C#" AutoEventWireup="true" Debug ="true" EnableEventValidation ="false" CodeFile="Default.aspx.cs" Inherits="_Default" %>

Export to PDF in Sharepoint Custom web part

1 Answers