Open new form based on ComboBox value using C# in Windows Forms Application

Hi ROHIT,

I have created sample code which full-fill your requirement.

C#

public partial class Form1 : Form
{
    public Form1()
    {
        InitializeComponent();
        DataTable dt = new DataTable();
        dt.Columns.Add("Title", typeof(string));
        dt.Rows.Add("Customers");
        dt.Rows.Add("Employees");
        dt.Rows.Add("Orders");
        DataRow dr = dt.NewRow();
        dr["Title"] = "Select";
        dt.Rows.InsertAt(dr, 0);
        comboBox1.DataSource = dt;
        comboBox1.DisplayMember = "Title";
        comboBox1.ValueMember = "Title";

    }

    private void comboBox1_SelectedIndexChanged(object sender, EventArgs e)
    {
        if (comboBox1.SelectedValue.ToString() == "Customers")
        {
            if (Application.OpenForms.OfType<Customers>().Count() == 1)
                Application.OpenForms.OfType<Customers>().First().Close();
            Customers frm = new Customers();
            frm.Show();
        }
        else if (comboBox1.SelectedValue.ToString() == "Employees")
        {
            if (Application.OpenForms.OfType<Employees>().Count() == 1)
                Application.OpenForms.OfType<Employees>().First().Close();
            Employees frm = new Employees();
            frm.Show();
        }
        else if (comboBox1.SelectedValue.ToString() == "Orders")
        {
            if (Application.OpenForms.OfType<Orders>().Count() == 1)
                Application.OpenForms.OfType<Orders>().First().Close();
            Orders frm = new Orders();
            frm.Show();
        }
    }
}

Screenshot