How do I set the windows default printer in C#?

Step 1: Paste the following code anywhere in your .cs file

  public static class PrinterClass
    {
        [DllImport("winspool.drv", CharSet = CharSet.Auto, SetLastError = true)]
        public static extern bool SetDefaultPrinter(string Printer);
    }

Step 2: Add the neccesary namespace i.e

using System.Runtime.InteropServices;

Step 3: Use the following function to set desired printer as default printer.

 PrinterClass.SetDefaultPrinter("Paste your desired Printer Name here");

Step 4: To get the list of all printers attached to your PC, you can use this code.

  private void FillListBox()
    {
        foreach (var p in PrinterSettings.InstalledPrinters)
        {
            cmbdefaultPrinter.Properties.Items.Add(p);
        }
    } 
//Here cmbdefaultPrinter is a combobox, you can fill the values into a list.

Namespaces required for the above code are:

using System.Drawing.Printing;
using System.Runtime.InteropServices;

using System;
using System.Drawing.Printing;
using System.Windows.Forms;
using System.Runtime.InteropServices;

namespace WindowsFormsApplication1
{
    public partial class Form1 : Form
    {

        private void listAllPrinters()
        {
            foreach (var item in PrinterSettings.InstalledPrinters)
            {    
                this.listBox1.Items.Add(item.ToString());
            }
        }

        private void listBox1_SelectedValueChanged(object sender, EventArgs e)
        {
            string pname = this.listBox1.SelectedItem.ToString();
            myPrinters.SetDefaultPrinter(pname);
        }


        public Form1()
        {
            InitializeComponent();
            listAllPrinters();
        }
    }

    public static class myPrinters
    {
        [DllImport("winspool.drv", CharSet = CharSet.Auto, SetLastError = true)]
        public static extern bool SetDefaultPrinter(string Name);

    }
}

Using the SetDefaultPrinter Windows API.

Here's how to pInvoke that.