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Friday, November 11, 2011

How to Print in ASP.NET 2.0


One of the most common functionality in any ASP.NET application is to print forms and controls. There are a lot of options to print forms using client scripts. In the article, we will see how to print controls in ASP.NET 2.0 using both server side code and javascript.
Step 1: Create a PrintHelper class. This class contains a method called PrintWebControl that can print any control like a GridView, DataGrid, Panel, TextBox etc. The class makes a call to window.print() that simulates the print button.
Note: I have not written this class and neither do I know the original author. I will be happy to add a reference in case someone knows. 
C# 
using System;
using System.Data;
using System.Configuration;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Web.UI.HtmlControls;
using System.IO;
using System.Text;
using System.Web.SessionState;
 
public class PrintHelper
{
    public PrintHelper()
    {
    }
 
    public static void PrintWebControl(Control ctrl)
    {
        PrintWebControl(ctrl, string.Empty);
    }
 
    public static void PrintWebControl(Control ctrl, string Script)
    {
        StringWriter stringWrite = new StringWriter();
        System.Web.UI.HtmlTextWriter htmlWrite = new System.Web.UI.HtmlTextWriter(stringWrite);
        if (ctrl is WebControl)
        {
            Unit w = new Unit(100, UnitType.Percentage); ((WebControl)ctrl).Width = w;
        }
        Page pg = new Page();
        pg.EnableEventValidation = false;
        if (Script != string.Empty)
        {
            pg.ClientScript.RegisterStartupScript(pg.GetType(),"PrintJavaScript", Script);
        }
        HtmlForm frm = new HtmlForm();
        pg.Controls.Add(frm);
        frm.Attributes.Add("runat""server");
        frm.Controls.Add(ctrl);
        pg.DesignerInitialize();
        pg.RenderControl(htmlWrite);
        string strHTML = stringWrite.ToString();
        HttpContext.Current.Response.Clear();
        HttpContext.Current.Response.Write(strHTML);
        HttpContext.Current.Response.Write("<script>window.print();</script>");
        HttpContext.Current.Response.End();
    }
}
 
VB.NET
Imports System
Imports System.Data
Imports System.Configuration
Imports System.Web
Imports System.Web.Security
Imports System.Web.UI
Imports System.Web.UI.WebControls
Imports System.Web.UI.WebControls.WebParts
Imports System.Web.UI.HtmlControls
Imports System.IO
Imports System.Text
Imports System.Web.SessionState
 
Public Class PrintHelper
    Public Sub New()
    End Sub
 
    Public Shared Sub PrintWebControl(ByVal ctrl As Control)
        PrintWebControl(ctrl, String.Empty)
    End Sub
 
    Public Shared Sub PrintWebControl(ByVal ctrl As Control, ByVal Script As String)
        Dim stringWrite As StringWriter = New StringWriter()
        Dim htmlWrite As System.Web.UI.HtmlTextWriter = New System.Web.UI.HtmlTextWriter(stringWrite)
        If TypeOf ctrl Is WebControl Then
            Dim w As Unit = New Unit(100, UnitType.Percentage)
            CType(ctrl, WebControl).Width = w
        End If
        Dim pg As Page = New Page()
        pg.EnableEventValidation = False
        If Script <> String.Empty Then
            pg.ClientScript.RegisterStartupScript(pg.GetType(), "PrintJavaScript", Script)
        End If
        Dim frm As HtmlForm = New HtmlForm()
        pg.Controls.Add(frm)
        frm.Attributes.Add("runat""server")
        frm.Controls.Add(ctrl)
        pg.DesignerInitialize()
        pg.RenderControl(htmlWrite)
        Dim strHTML As String = stringWrite.ToString()
        HttpContext.Current.Response.Clear()
        HttpContext.Current.Response.Write(strHTML)
        HttpContext.Current.Response.Write("<script>window.print();</script>")
        HttpContext.Current.Response.End()
    End Sub
End Class
 
Step 2: Create two pages, Default.aspx and Print.aspx. Default.aspx will contain the controls to be printed. Print.aspx will act as a popup page to invoke the print functionality.
Step 3: In your Default.aspx, drag and drop a few controls that you would like to print. To print a group of controls, place them all in a container control like a panel. This way if we print the panel using our PrintHelper class, all the controls inside the panel gets printed.
Step 4: Add a print button to the Default.aspx and in the code behind, type the following code:
C#
protected void btnPrint_Click(object sender, EventArgs e)
    {
        Session["ctrl"] = Panel1;
        ClientScript.RegisterStartupScript(this.GetType(), "onclick""<script language=javascript>window.open('Print.aspx','PrintMe','height=300px,width=300px,scrollbars=1');</script>");
    }
VB.NET
Protected Sub btnPrint_Click(ByVal sender As ObjectByVal e As System.EventArgs) Handles btnPrint.Click
        Session("ctrl") = Panel1
        ClientScript.RegisterStartupScript(Me.GetType(), "onclick""<script language=javascript>window.open('Print.aspx','PrintMe','height=300px,width=300px,scrollbars=1');</script>")
End Sub
The code stores the control in a Session variable to be accessed in the pop up page, Print.aspx. If you want to print directly on button click, call the Print functionality in the following manner :
 
PrintHelper.PrintWebControl(Panel1);
 
Step 5: In the Page_Load event of Print.aspx.cs, add the following code:
C#
 
protected void Page_Load(object sender, EventArgs e)
    {
        Control ctrl = (Control)Session["ctrl"];
        PrintHelper.PrintWebControl(ctrl);
    }
VB.NET
Protected Sub Page_Load(ByVal sender As ObjectByVal e As System.EventArgs) Handles Me.Load
        Dim ctrl As Control = CType(Session("ctrl"), Control)
        PrintHelper.PrintWebControl(ctrl)
End Sub
 
Well that’s it. Try out the sample attached with this article and print any control you desire. The entire source code of this article can be downloaded over here.
I hope this article was useful and I thank you for viewing it.

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