How to use multiple forms in c#.

check this
http://msdn.microsoft.com/en-us/library/aa984329(v=VS.71).aspx[^]

I'm going to answer your question very "literally," assuming that you want to start a WinForms application with its "Primary Form" hidden, and an InitialForm displayed where the user enters a name, and then, when the user closes the InitialForm, you want your PrimaryForm (the Application) to become visible, and to have "captured" the information entered on the InitialForm, so you can use it in your Application (the PrimaryForm).

So, the InitialForm code is something like this: assuming you have a TextBox, and a Button, on it, and the Button Click Event wired-up:

public partial class InitialForm : Form
{
    public InitialForm() { InitializeComponent(); }

    // this 'exposes a string to the 'outside
    public string UserEnteredText { get; private set; }

    // see below for why you need to implement this
    //private void InitialForm_FormClosing(object sender, FormClosingEventArgs e)
    //{
        //UserEnteredText = textBox1.Text;
    //}

    private void button1_Click(object sender, EventArgs e)
    {
        UserEnteredText = textBox1.Text;

        Close();
    }
}

So, the PrimaryForm (that you start your Application with) contains:

// this code would not work in the Form Load Event
private void PrimaryForm_Shown(object sender, EventArgs e)
{
    Visible = false;

    InitialForm iform = new InitialForm();

    iform.FormClosing += iform_FormClosing;

    iform.Show();
}

// this will contain the text the user entered on the InitialForm
private string UserEnteredText;

// note that this could be called by either the user pressing
// the Button on the InitialiForm, or by closing the InitialForm
// by clicking its 'CloseBox
private void iform_FormClosing(object sender, FormClosingEventArgs e)
{
    // note that we have to cast to 'InitialForm here
    // to access its public property
    UserEnteredText = (sender as InitialForm).UserEnteredText;
    
    // show the Primary Form
    Show();

    // for testing only
    MessageBox.Show("The user entered: " + UserEnteredText);
}

But, wait: what happened if the InitialForm had a CloseBox, and the user closed it ? The public string property of the InitialForm would never have been set: so you need to add a FormClosing EventHandler to the InitialForm, and "wire it up" (as shown in the commented out code above for InitialForm):

private void InitialForm_FormClosing(object sender, FormClosingEventArgs e)
{
    UserEnteredText = textBox1.Text;
}

Consider the upside, and downside, of using the technique shown here:

1. upside: InitialForm is disposed of: you never "kept a reference to it." You didn't have to write a custom Event in the InitialForm, and subscribe to it in the Primary Form. You didn't need (praise be) to muck around with WinForm's tricky Property Change notification. You didn't need to do anything "modal."

2. downside: You don't keep InitialForm around for possible re-use: and that's likely (?). Writing a custom Event in InitialForm, triggered by the Button Click Event, that you subscribed to in the PrimaryForm, might well result in "cleaner," more understandable, maintainable code.

Finally: by simply making InitialForm have no CloseBox, you can eliminate the fancy-dancing shown here the handle the case of the user closing InitialForm in a way that prevents you from "getting" the information from its TextBox.

Hi,

Try this

private void btnShowForm_OnClick(...)
{
    if(/* perform credential test here */)
    {
        (new Form2()).Show(); // create and show the other form
        this.Hide(); // Hides this form
    }
    else
        MessageBox.Show("your Message!");
}

also Visit these links..

http://www.homeandlearn.co.uk/csharp/csharp_s13p1.html[^]


http://support.microsoft.com/kb/821773[^]

I had a similar task: -
Main form to open and pass values (from a textbox) to a new form which could modify, and pass the modified data back to the original.
This set of solutions, plus a lot of trial and error, helped me come up with this solution : -
Main form (form1) add a button and a text box.
Sub form (form2) add a button and a textbox, then in the form properties set "ControlBox" property to "false"

Code for Form 1

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;

namespace TwoForms
{
    public partial class Form1 : Form
    {
        public static TextBox tb = new TextBox();
        Form2 secondForm = new Form2();

        public Form1()
        {
            InitializeComponent();
        }

        private void Form1_Load(object sender, EventArgs e)
        {
            tb = textBox1;
        }

        private void button1_Click(object sender, EventArgs e)
        {
            secondForm.Show();
        }
    }

}

Code for form 2: -

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;

namespace TwoForms
{
    public partial class Form2 : Form
    {
        public Form2()
        {
            InitializeComponent();
        }

        private void button1_Click(object sender, EventArgs e)
        {
            this.Hide();
        }

        private void Form2_Load(object sender, EventArgs e)
        {
            textBox1.Text = Form1.tb.Text;
        }

        private void textBox1_TextChanged(object sender, EventArgs e)
        {
            Form1.tb.Text = textBox1.Text;
        }
    }
}