Calling a hidden form

[ahmad.humyn]

I want to call a hidden form. My code goes something like in which the
main calls form1. form1 has a button which creates & calls form2 and
hides itself. Now I have a button in form2 which if pressed should
dispose form2 and then unhide and focus form1.

--------------------------------------------------
static void Main()
{
.....
Application.Run (new Form1());
}
---------------------------------------------------
public partial class Form1 : Form
{
public Form1()
{
InitializeCompo nent();
}

private void button1_Click(o bject sender, EventArgs e)
{
Form2 frm = new Form2();
frm.Show();
this.Hide();
}
}
----------------------------------------------------
public partial class Form2 : Form
{
public Form2()
{
InitializeCompo nent();
}

private void button1_Click(o bject sender, EventArgs e)
{
this.Dispose();
// Somehow Form1.Show();
// where Form1 is the hidden form
}
}

Please help out here. I will greatly appreciate it.

Regards.

[Dave Sexton]

Hi Ahmad,

Using a TabControl might be a better UI design but if your really want to toggle between two Forms you could just set Form1 as the
Owner of Form2.

{Form1}
private void button1_Click(o bject sender, EventArgs e)
{
Form2 form2 = new Form2();
form2 Owner = this;
form2.Show();
this.Hide();
}

{Form2}
private void button1_Click(o bject sender, EventArgs e)
{
Owner.Show();
this.Dispose();
}

--
Dave Sexton

<ah*********@gm ail.comwrote in message news:11******** **************@ i42g2000cwa.goo glegroups.com.. .

>I want to call a hidden form. My code goes something like in which the
main calls form1. form1 has a button which creates & calls form2 and
hides itself. Now I have a button in form2 which if pressed should
dispose form2 and then unhide and focus form1.

--------------------------------------------------
static void Main()
{
.....
Application.Run (new Form1());
}
---------------------------------------------------
public partial class Form1 : Form
{
public Form1()
{
InitializeCompo nent();
}

private void button1_Click(o bject sender, EventArgs e)
{
Form2 frm = new Form2();
frm.Show();
this.Hide();
}
}
----------------------------------------------------
public partial class Form2 : Form
{
public Form2()
{
InitializeCompo nent();
}

private void button1_Click(o bject sender, EventArgs e)
{
this.Dispose();
// Somehow Form1.Show();
// where Form1 is the hidden form
}
}

Please help out here. I will greatly appreciate it.

Regards.

[ahmad.humyn]

Dear Dave, I tried what you suggested and it seemed completely logical
to me what you told. :
I set this in my form1 code -frm.Owner = this; and then I tried doing
this in my form2 code Owner.Show(). But Visual Studio gives a runtime
error on Owner.Show saying that "NullReferenceE xception was Unhandled
:: Object reference not set to an instance of an object."

What should I do? Greatly appreciate your help

Regards

[Dave Sexton]

Hi Ahmad,

Sounds like Owner is null. Are you sure you set the correct Form's Owner property? The code I posted works. Post your code and
I'll take a look.

--
Dave Sexton

<ah*********@gm ail.comwrote in message news:11******** **************@ h48g2000cwc.goo glegroups.com.. .

Dear Dave, I tried what you suggested and it seemed completely logical
to me what you told. :
I set this in my form1 code -frm.Owner = this; and then I tried doing
this in my form2 code Owner.Show(). But Visual Studio gives a runtime
error on Owner.Show saying that "NullReferenceE xception was Unhandled
:: Object reference not set to an instance of an object."

What should I do? Greatly appreciate your help

Regards

[ahmad.humyn]

---------------Program.cs-------------------------
using System;
using System.Collecti ons.Generic;
using System.Windows. Forms;

namespace WindowsApplicat ion3
{
static class Program
{
/// <summary>
/// The main entry point for the application.
/// </summary>
[STAThread]
static void Main()
{
Application.Ena bleVisualStyles ();
Application.Set CompatibleTextR enderingDefault (false);
Application.Run (new Form1());
}
}
}
-------------------------------------------------------
------------Form1.designer. cs----------------
namespace WindowsApplicat ion3
{
partial class Form1
{
/// <summary>
/// Required designer variable.
/// </summary>
private System.Componen tModel.IContain er components = null;

/// <summary>
/// Clean up any resources being used.
/// </summary>
/// <param name="disposing ">true if managed resources should be
disposed; otherwise, false.</param>
protected override void Dispose(bool disposing)
{
if (disposing && (components != null))
{
components.Disp ose();
}
base.Dispose(di sposing);
}

#region Windows Form Designer generated code

/// <summary>
/// Required method for Designer support - do not modify
/// the contents of this method with the code editor.
/// </summary>
private void InitializeCompo nent()
{
this.button1 = new System.Windows. Forms.Button();
this.button2 = new System.Windows. Forms.Button();
this.button3 = new System.Windows. Forms.Button();
this.SuspendLay out();
//
// button1
//
this.button1.Lo cation = new System.Drawing. Point(35, 15);
this.button1.Na me = "button1";
this.button1.Si ze = new System.Drawing. Size(117, 39);
this.button1.Ta bIndex = 0;
this.button1.Te xt = "Call form2 and HIDE";
this.button1.Us eVisualStyleBac kColor = true;
this.button1.Cl ick += new
System.EventHan dler(this.butto n1_Click);
//
// button2
//
this.button2.Lo cation = new System.Drawing. Point(35, 66);
this.button2.Na me = "button2";
this.button2.Si ze = new System.Drawing. Size(117, 38);
this.button2.Ta bIndex = 1;
this.button2.Te xt = "Call form2 and DISPOSE";
this.button2.Us eVisualStyleBac kColor = true;
//
// button3
//
this.button3.Lo cation = new System.Drawing. Point(35, 119);
this.button3.Na me = "button3";
this.button3.Si ze = new System.Drawing. Size(117, 37);
this.button3.Ta bIndex = 2;
this.button3.Te xt = "Exit App";
this.button3.Us eVisualStyleBac kColor = true;
this.button3.Cl ick += new
System.EventHan dler(this.butto n3_Click);
//
// Form1
//
this.AutoScaleD imensions = new System.Drawing. SizeF(6F,
13F);
this.AutoScaleM ode =
System.Windows. Forms.AutoScale Mode.Font;
this.ClientSize = new System.Drawing. Size(184, 175);
this.Controls.A dd(this.button3 );
this.Controls.A dd(this.button2 );
this.Controls.A dd(this.button1 );
this.FormBorder Style =
System.Windows. Forms.FormBorde rStyle.FixedSin gle;
this.Name = "Form1";
this.Text = "Form1";
this.ResumeLayo ut(false);

}

#endregion

private System.Windows. Forms.Button button1;
private System.Windows. Forms.Button button2;
private System.Windows. Forms.Button button3;
}
}
----------------------------------------------------------
--------------------Form1.cs------------------------
using System;
using System.Collecti ons.Generic;
using System.Componen tModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows. Forms;

namespace WindowsApplicat ion3
{
public partial class Form1 : Form
{
public Form1()
{
InitializeCompo nent();
}

private void button1_Click(o bject sender, EventArgs e)
{
Form2 frm = new Form2();
frm.Owner = this;
frm.Show();
this.Hide();
}

private void button2_Click(o bject sender, EventArgs e)
{
Form2 frm = new Form2();
frm.Show();
this.Dispose();
}

private void button3_Click(o bject sender, EventArgs e)
{
this.Close();
//Application.Exi t();
}

}
}
-------------------------------------------------------
------------Form2.designer. cs----------------
namespace WindowsApplicat ion3
{
partial class Form2
{
/// <summary>
/// Required designer variable.
/// </summary>
private System.Componen tModel.IContain er components = null;

/// <summary>
/// Clean up any resources being used.
/// </summary>
/// <param name="disposing ">true if managed resources should be
disposed; otherwise, false.</param>
protected override void Dispose(bool disposing)
{
if (disposing && (components != null))
{
components.Disp ose();
}
base.Dispose(di sposing);
}

#region Windows Form Designer generated code

/// <summary>
/// Required method for Designer support - do not modify
/// the contents of this method with the code editor.
/// </summary>
private void InitializeCompo nent()
{
this.button1 = new System.Windows. Forms.Button();
this.button2 = new System.Windows. Forms.Button();
this.SuspendLay out();
//
// button1
//
this.button1.Lo cation = new System.Drawing. Point(42, 12);
this.button1.Na me = "button1";
this.button1.Si ze = new System.Drawing. Size(107, 34);
this.button1.Ta bIndex = 0;
this.button1.Te xt = "Call Form1";
this.button1.Us eVisualStyleBac kColor = true;
this.button1.Cl ick += new
System.EventHan dler(this.butto n1_Click);
//
// button2
//
this.button2.Lo cation = new System.Drawing. Point(42, 64);
this.button2.Na me = "button2";
this.button2.Si ze = new System.Drawing. Size(107, 35);
this.button2.Ta bIndex = 1;
this.button2.Te xt = "Exit App";
this.button2.Us eVisualStyleBac kColor = true;
this.button2.Cl ick += new
System.EventHan dler(this.butto n2_Click);
//
// Form2
//
this.AutoScaleD imensions = new System.Drawing. SizeF(6F,
13F);
this.AutoScaleM ode =
System.Windows. Forms.AutoScale Mode.Font;
this.ClientSize = new System.Drawing. Size(189, 116);
this.Controls.A dd(this.button2 );
this.Controls.A dd(this.button1 );
this.FormBorder Style =
System.Windows. Forms.FormBorde rStyle.FixedSin gle;
this.Name = "Form2";
this.Text = "Form2";
this.ResumeLayo ut(false);

}

#endregion

private System.Windows. Forms.Button button1;
private System.Windows. Forms.Button button2;
}
}
----------------------------------------------------------
--------------------Form2.cs------------------------
using System;
using System.Collecti ons.Generic;
using System.Componen tModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows. Forms;

namespace WindowsApplicat ion3
{
public partial class Form2 : Form
{
public Form2()
{
InitializeCompo nent();
}

private void button1_Click(o bject sender, EventArgs e)
{
this.Dispose();
Owner.Show();
}

private void button2_Click(o bject sender, EventArgs e)
{
// MessageBox.Show (Application.Al lowQuit.ToStrin g());
Application.Exi t();
}
}
}

---------------------------------------------------------
=============== ==============

Thanks for helping out Dave. Really new to this framework and have
small problems like these!

Regards

[Dave Sexton]

Hi Ahmad,

This is a snippet from your code (Form2.cs):

private void button1_Click(o bject sender, EventArgs e)
{
this.Dispose();
Owner.Show();
}

Notice that you called Dispose on the Form before you tried to access its Owner property (which is actually the same as this.Owner).
Once you dispose of an object, in this case the Form, you shouldn't try to access any of its members. Reversing the order in which
you call these two methods should do the trick:

// Access this.Owner property and show the Form
this.Owner.Show ();

// Dispose of this Form.
this.Dispose();

--
Dave Sexton

<ah*********@gm ail.comwrote in message news:11******** **************@ m73g2000cwd.goo glegroups.com.. .

---------------Program.cs-------------------------
using System;
using System.Collecti ons.Generic;
using System.Windows. Forms;

namespace WindowsApplicat ion3
{
static class Program
{
/// <summary>
/// The main entry point for the application.
/// </summary>
[STAThread]
static void Main()
{
Application.Ena bleVisualStyles ();
Application.Set CompatibleTextR enderingDefault (false);
Application.Run (new Form1());
}
}
}
-------------------------------------------------------
------------Form1.designer. cs----------------
namespace WindowsApplicat ion3
{
partial class Form1
{
/// <summary>
/// Required designer variable.
/// </summary>
private System.Componen tModel.IContain er components = null;

/// <summary>
/// Clean up any resources being used.
/// </summary>
/// <param name="disposing ">true if managed resources should be
disposed; otherwise, false.</param>
protected override void Dispose(bool disposing)
{
if (disposing && (components != null))
{
components.Disp ose();
}
base.Dispose(di sposing);
}

#region Windows Form Designer generated code

/// <summary>
/// Required method for Designer support - do not modify
/// the contents of this method with the code editor.
/// </summary>
private void InitializeCompo nent()
{
this.button1 = new System.Windows. Forms.Button();
this.button2 = new System.Windows. Forms.Button();
this.button3 = new System.Windows. Forms.Button();
this.SuspendLay out();
//
// button1
//
this.button1.Lo cation = new System.Drawing. Point(35, 15);
this.button1.Na me = "button1";
this.button1.Si ze = new System.Drawing. Size(117, 39);
this.button1.Ta bIndex = 0;
this.button1.Te xt = "Call form2 and HIDE";
this.button1.Us eVisualStyleBac kColor = true;
this.button1.Cl ick += new
System.EventHan dler(this.butto n1_Click);
//
// button2
//
this.button2.Lo cation = new System.Drawing. Point(35, 66);
this.button2.Na me = "button2";
this.button2.Si ze = new System.Drawing. Size(117, 38);
this.button2.Ta bIndex = 1;
this.button2.Te xt = "Call form2 and DISPOSE";
this.button2.Us eVisualStyleBac kColor = true;
//
// button3
//
this.button3.Lo cation = new System.Drawing. Point(35, 119);
this.button3.Na me = "button3";
this.button3.Si ze = new System.Drawing. Size(117, 37);
this.button3.Ta bIndex = 2;
this.button3.Te xt = "Exit App";
this.button3.Us eVisualStyleBac kColor = true;
this.button3.Cl ick += new
System.EventHan dler(this.butto n3_Click);
//
// Form1
//
this.AutoScaleD imensions = new System.Drawing. SizeF(6F,
13F);
this.AutoScaleM ode =
System.Windows. Forms.AutoScale Mode.Font;
this.ClientSize = new System.Drawing. Size(184, 175);
this.Controls.A dd(this.button3 );
this.Controls.A dd(this.button2 );
this.Controls.A dd(this.button1 );
this.FormBorder Style =
System.Windows. Forms.FormBorde rStyle.FixedSin gle;
this.Name = "Form1";
this.Text = "Form1";
this.ResumeLayo ut(false);

}

#endregion

private System.Windows. Forms.Button button1;
private System.Windows. Forms.Button button2;
private System.Windows. Forms.Button button3;
}
}
----------------------------------------------------------
--------------------Form1.cs------------------------
using System;
using System.Collecti ons.Generic;
using System.Componen tModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows. Forms;

namespace WindowsApplicat ion3
{
public partial class Form1 : Form
{
public Form1()
{
InitializeCompo nent();
}

private void button1_Click(o bject sender, EventArgs e)
{
Form2 frm = new Form2();
frm.Owner = this;
frm.Show();
this.Hide();
}

private void button2_Click(o bject sender, EventArgs e)
{
Form2 frm = new Form2();
frm.Show();
this.Dispose();
}

private void button3_Click(o bject sender, EventArgs e)
{
this.Close();
//Application.Exi t();
}

}
}
-------------------------------------------------------
------------Form2.designer. cs----------------
namespace WindowsApplicat ion3
{
partial class Form2
{
/// <summary>
/// Required designer variable.
/// </summary>
private System.Componen tModel.IContain er components = null;

/// <summary>
/// Clean up any resources being used.
/// </summary>
/// <param name="disposing ">true if managed resources should be
disposed; otherwise, false.</param>
protected override void Dispose(bool disposing)
{
if (disposing && (components != null))
{
components.Disp ose();
}
base.Dispose(di sposing);
}

#region Windows Form Designer generated code

/// <summary>
/// Required method for Designer support - do not modify
/// the contents of this method with the code editor.
/// </summary>
private void InitializeCompo nent()
{
this.button1 = new System.Windows. Forms.Button();
this.button2 = new System.Windows. Forms.Button();
this.SuspendLay out();
//
// button1
//
this.button1.Lo cation = new System.Drawing. Point(42, 12);
this.button1.Na me = "button1";
this.button1.Si ze = new System.Drawing. Size(107, 34);
this.button1.Ta bIndex = 0;
this.button1.Te xt = "Call Form1";
this.button1.Us eVisualStyleBac kColor = true;
this.button1.Cl ick += new
System.EventHan dler(this.butto n1_Click);
//
// button2
//
this.button2.Lo cation = new System.Drawing. Point(42, 64);
this.button2.Na me = "button2";
this.button2.Si ze = new System.Drawing. Size(107, 35);
this.button2.Ta bIndex = 1;
this.button2.Te xt = "Exit App";
this.button2.Us eVisualStyleBac kColor = true;
this.button2.Cl ick += new
System.EventHan dler(this.butto n2_Click);
//
// Form2
//
this.AutoScaleD imensions = new System.Drawing. SizeF(6F,
13F);
this.AutoScaleM ode =
System.Windows. Forms.AutoScale Mode.Font;
this.ClientSize = new System.Drawing. Size(189, 116);
this.Controls.A dd(this.button2 );
this.Controls.A dd(this.button1 );
this.FormBorder Style =
System.Windows. Forms.FormBorde rStyle.FixedSin gle;
this.Name = "Form2";
this.Text = "Form2";
this.ResumeLayo ut(false);

}

#endregion

private System.Windows. Forms.Button button1;
private System.Windows. Forms.Button button2;
}
}
----------------------------------------------------------
--------------------Form2.cs------------------------
using System;
using System.Collecti ons.Generic;
using System.Componen tModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows. Forms;

namespace WindowsApplicat ion3
{
public partial class Form2 : Form
{
public Form2()
{
InitializeCompo nent();
}

private void button1_Click(o bject sender, EventArgs e)
{
this.Dispose();
Owner.Show();
}

private void button2_Click(o bject sender, EventArgs e)
{
// MessageBox.Show (Application.Al lowQuit.ToStrin g());
Application.Exi t();
}
}
}

---------------------------------------------------------
=============== ==============

Thanks for helping out Dave. Really new to this framework and have
small problems like these!

Regards

[ahmad.humyn]

How dumb one can be !! :) Thanks alot Dave...a true logical
explanation.

Kudos,
Ahmad