ASP.NET

ReportDocument rptPrint = new ReportDocument();
rptPrint.Load(Server.MapPath("Reports").ToString() + "\\rptSales.rpt");
//Report displaying in Screen
DataSet dsData = (DataSet)Session["EmpData"];
rptPrint.SetDataSource(dsData);
CrystalReportViewer1.ReportSource = rptPrint;
CrystalReportViewer1.DataBind();
//Report directly printing by Printer
string strSystemName = "\\\\RAJA\\";
string strPrinterName = "SAMSUNG";
rptPrint.PrintOptions.PrinterName = strSystemName + strPrinterName;
rptPrint.PrintToPrinter(1, false, 0, 0);
rptPrint.Close();
rptPrint.Dispose();

System.Net.IPHostEntry host;
host = System.Net.Dns.GetHostEntry(Context.Request.ServerVariables["REMOTE_HOST"]);
string strSystemName = host.HostName;

Protected Sub Button1_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles Button1.Click
    Dim ocn As New System.Data.OracleClient.OracleConnection
    Dim oda As New System.Data.OracleClient.OracleDataAdapter("select empno,ename from emp", ocn)
    Dim ods As New System.Data.DataSet()
    ocn.ConnectionString = "Data Source=orcl;User ID=scott;Password=pw;Unicode=True"
    oda.Fill(ods)
    Dim rptprint As New CrystalDecisions.CrystalReports.Engine.ReportDocument()
    rptprint.Load(Server.MapPath("Reports").ToString() + "\\CrystalReport.rpt")
    rptprint.SetDataSource(ods)
    CrystalReportViewer1.ReportSource = rptprint
    CrystalReportViewer1.DataBind()
    ''rptprint.PrintOptions.PrinterName = DefaultPrinterName()
    ''rptprint.PrintToPrinter(1, False, 0, 0)
    TextBox1.Text = DefaultPrinterName()
    rptprint.Close()
    rptprint.Dispose()
    ocn.Close()
    ocn.Dispose()
    ods.Dispose()
    oda.Dispose()
End Sub
Public Shared Function DefaultPrinterName() As String
    Dim oPS As New System.Drawing.Printing.PrinterSettings
    Try
        DefaultPrinterName = oPS.PrinterName
    Catch ex As System.Exception
        DefaultPrinterName = ""
    Finally
        oPS = Nothing
    End Try
End Function

System.Net.IPHostEntry host;
host = System.Net.Dns.GetHostEntry(Context.Request.ServerVariables["REMOTE_HOST"]);
string strSystemName = host.HostName;//You will get client machine name like \\RAJA
string strPrinterName = "Generic / Text Only";//Mention here your client machine default printer
rptPrint.PrintOptions.PrinterName = strSystemName + "\\" + strPrinterName;

<CR:CrystalReportViewer ID="CrystalReportViewer1" runat="server" AutoDataBind="true"
                PrintMode="ActiveX" EnableDatabaseLogonPrompt="false" />
        <asp:Button ID="Button1" runat="server" Text="Button" />

Imports CrystalDecisions.Shared
Imports CrystalDecisions.CrystalReports.Engine
Imports CrystalDecisions.ReportSource
Imports CrystalDecisions.Web

Partial Public Class _Default
    Inherits System.Web.UI.Page

    Dim rptprint As New CrystalDecisions.CrystalReports.Engine.ReportDocument()

    Protected Sub Page_Unload(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Unload
        rptprint.Close()
        rptprint.Dispose()
    End Sub

    Protected Sub Button1_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles Button1.Click
        Dim ocn As New System.Data.SqlClient.SqlConnection
        Dim oda As New System.Data.SqlClient.SqlDataAdapter("select * from Employees", ocn)
        Dim ods As New System.Data.DataSet()
        ocn.ConnectionString = "Data Source=RAJA;User ID=sa;Password=123;Initial Catalog=Northwind"
        oda.Fill(ods)

        rptprint.Load("C:\CrystalReport1.rpt")
        rptprint.SetDataSource(ods)

        ' For DB Login
        Dim crtableLogoninfos As New TableLogOnInfos()
        Dim crtableLogoninfo As New TableLogOnInfo()
        Dim crConnectionInfo As New ConnectionInfo()
        Dim CrTables As Tables
        crConnectionInfo.ServerName = "RAJA"
        crConnectionInfo.DatabaseName = "Northwind"
        crConnectionInfo.UserID = "sa"
        crConnectionInfo.Password = "123"

        CrTables = rptprint.Database.Tables
        For Each CrTable As CrystalDecisions.CrystalReports.Engine.Table In CrTables
            crtableLogoninfo = CrTable.LogOnInfo
            crtableLogoninfo.ConnectionInfo = crConnectionInfo
            CrTable.ApplyLogOnInfo(crtableLogoninfo)
        Next
        '/ For DB Login

        CrystalReportViewer1.ReportSource = rptprint
        CrystalReportViewer1.DataBind()

        ocn.Close()
        ocn.Dispose()
        ods.Dispose()
        oda.Dispose()
    End Sub
End Class