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c# How to swap between forms

My application has a need to hide an initial form and open any one of four new forms. I can hide the initial and open the selected form with:
private void btn_Option1_Click(object sender, EventArgs e){
Visible = false;
Application x = new Application();
x.show();
}
My question is how to close the second form and reopen the original form? Or I suppose it would be plausible to close each form on each form opening, but that seems wasteful.

It sounds like you need the FormClosed event.
When you create instances of the new Form from your initial Form you can subscribe to the new Form's FormClosed event and show your initial Form from the handler.
This way, whenever one of your new Forms close, the event handler will fire and your initial Form will become visible again.
// This is a method that you would add to your initial Form.
private void SubForm_Closed(object sender, FormClosedEventArgs e)
{
Visible = true;
}
private void btn_Option1_Click(object sender, EventArgs e)
{
Visible = false;
Application x = new Application();
x.FormClosed += SubForm_Closed;
x.show();
}

If you use Hide(), the form "essentially" disappears, you won't even see it in the taskbar. Then you can open by Showing it from one of the subsequent forms. I threw the below together and only tested it quickly so YMMV, you'll need to clean it up and make it work for you, but it should illustrate the point. Create a Windows Form Application. Call it "WindowsFormsApp2" since that's what I used. Paste in the below code:
using System;
using System.Windows.Forms;
namespace WindowsFormsApp2
{
public partial class Form1 : Form
{
public Form1()
{
InitializeComponent();
}
Form2 form2;
Form3 form3;
Form4 form4;
Form5 form5;
private void button1_Click_1(object sender, EventArgs e)
{
if (checkBox1.Checked)
{
form2 = new Form2(this);
form2.Show();
}
if (checkBox2.Checked)
{
form3 = new Form3(this);
form3.Show();
}
if (checkBox3.Checked)
{
form4 = new Form4(this);
form4.Show();
}
if (checkBox4.Checked)
{
form5 = new Form5(this);
form5.Show();
}
this.Hide();
}
}
}
Paste the below code into the Form1 designer:
namespace WindowsFormsApp2
{
partial class Form1
{
/// <summary>
/// Required designer variable.
/// </summary>
private System.ComponentModel.IContainer 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.Dispose();
}
base.Dispose(disposing);
}
#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 InitializeComponent()
{
this.groupBox1 = new System.Windows.Forms.GroupBox();
this.checkBox1 = new System.Windows.Forms.CheckBox();
this.checkBox2 = new System.Windows.Forms.CheckBox();
this.checkBox3 = new System.Windows.Forms.CheckBox();
this.checkBox4 = new System.Windows.Forms.CheckBox();
this.button1 = new System.Windows.Forms.Button();
this.groupBox1.SuspendLayout();
this.SuspendLayout();
//
// groupBox1
//
this.groupBox1.Controls.Add(this.checkBox4);
this.groupBox1.Controls.Add(this.checkBox3);
this.groupBox1.Controls.Add(this.checkBox2);
this.groupBox1.Controls.Add(this.checkBox1);
this.groupBox1.Location = new System.Drawing.Point(12, 12);
this.groupBox1.Name = "groupBox1";
this.groupBox1.Size = new System.Drawing.Size(274, 73);
this.groupBox1.TabIndex = 0;
this.groupBox1.TabStop = false;
this.groupBox1.Text = "Forms";
//
// checkBox1
//
this.checkBox1.AutoSize = true;
this.checkBox1.Location = new System.Drawing.Point(17, 32);
this.checkBox1.Name = "checkBox1";
this.checkBox1.Size = new System.Drawing.Size(55, 17);
this.checkBox1.TabIndex = 0;
this.checkBox1.Text = "Form2";
this.checkBox1.UseVisualStyleBackColor = true;
//
// checkBox2
//
this.checkBox2.AutoSize = true;
this.checkBox2.Location = new System.Drawing.Point(78, 32);
this.checkBox2.Name = "checkBox2";
this.checkBox2.Size = new System.Drawing.Size(55, 17);
this.checkBox2.TabIndex = 1;
this.checkBox2.Text = "Form3";
this.checkBox2.UseVisualStyleBackColor = true;
//
// checkBox3
//
this.checkBox3.AutoSize = true;
this.checkBox3.Location = new System.Drawing.Point(139, 32);
this.checkBox3.Name = "checkBox3";
this.checkBox3.Size = new System.Drawing.Size(55, 17);
this.checkBox3.TabIndex = 2;
this.checkBox3.Text = "Form4";
this.checkBox3.UseVisualStyleBackColor = true;
//
// checkBox4
//
this.checkBox4.AutoSize = true;
this.checkBox4.Location = new System.Drawing.Point(200, 32);
this.checkBox4.Name = "checkBox4";
this.checkBox4.Size = new System.Drawing.Size(55, 17);
this.checkBox4.TabIndex = 3;
this.checkBox4.Text = "Form5";
this.checkBox4.UseVisualStyleBackColor = true;
//
// button1
//
this.button1.Location = new System.Drawing.Point(12, 91);
this.button1.Name = "button1";
this.button1.Size = new System.Drawing.Size(199, 23);
this.button1.TabIndex = 1;
this.button1.Text = "Open Selected Forms";
this.button1.UseVisualStyleBackColor = true;
this.button1.Click += new System.EventHandler(this.button1_Click_1);
//
// Form1
//
this.AutoScaleDimensions = new System.Drawing.SizeF(6F, 13F);
this.AutoScaleMode = System.Windows.Forms.AutoScaleMode.Font;
this.ClientSize = new System.Drawing.Size(800, 450);
this.Controls.Add(this.button1);
this.Controls.Add(this.groupBox1);
this.Name = "Form1";
this.Text = "Form1";
this.groupBox1.ResumeLayout(false);
this.groupBox1.PerformLayout();
this.ResumeLayout(false);
}
#endregion
private System.Windows.Forms.GroupBox groupBox1;
private System.Windows.Forms.CheckBox checkBox4;
private System.Windows.Forms.CheckBox checkBox3;
private System.Windows.Forms.CheckBox checkBox2;
private System.Windows.Forms.CheckBox checkBox1;
private System.Windows.Forms.Button button1;
}
}
Add 4 Windows Forms: Form2, Form3, Form4 and Form5.
Paste in the below code to each and just change the form name on each to it's correct name (Form3, Form4, Form5):
using System;
using System.Windows.Forms;
namespace WindowsFormsApp2
{
public partial class Form2 : Form
{
public Form2(Form1 Form1In)
{
InitializeComponent();
form1 = Form1In;
}
Form1 form1;
private void button1_Click(object sender, EventArgs e)
{
form1.Show();
}
}
}
Finally paste in the below code to the designer of each form and change the name for the forms other than Form2 to their respective name:
namespace WindowsFormsApp2
{
partial class Form2
{
/// <summary>
/// Required designer variable.
/// </summary>
private System.ComponentModel.IContainer 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.Dispose();
}
base.Dispose(disposing);
}
#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 InitializeComponent()
{
this.button1 = new System.Windows.Forms.Button();
this.SuspendLayout();
//
// button1
//
this.button1.Location = new System.Drawing.Point(22, 21);
this.button1.Name = "button1";
this.button1.Size = new System.Drawing.Size(104, 23);
this.button1.TabIndex = 0;
this.button1.Text = "Show Form1";
this.button1.UseVisualStyleBackColor = true;
this.button1.Click += new System.EventHandler(this.button1_Click);
//
// Form2
//
this.AutoScaleDimensions = new System.Drawing.SizeF(6F, 13F);
this.AutoScaleMode = System.Windows.Forms.AutoScaleMode.Font;
this.ClientSize = new System.Drawing.Size(800, 450);
this.Controls.Add(this.button1);
this.Name = "Form2";
this.Text = "Form2";
this.ResumeLayout(false);
}
#endregion
private System.Windows.Forms.Button button1;
}
}
Then run it.

Here's a shiny new wheel. It concentrates all the logic in a Manager class.
A SubForm Base Class
First, we'll create a base class for all the sub forms. This way, you don't need to put the form switching logic into every form.
Create a new Form in your project, name it ShowHideFormBase , change to the "View Code" view and change the boilerplate so it looks like this:
public partial class ShowHideFormBase : Form
{
public ShowHideFormManager Manager { get; private set; }
public ShowHideFormBase()
{
Manager = null;
InitializeComponent();
}
public void SetManager (ShowHideFormManager manager)
{
Manager = manager;
}
}
We'll create the Manager class in a bit
I really wanted to have a constructor on ShowHideFormBase that took a ShowHideFormManager instance as a parameter. The Windows Forms designer really doesn't like having forms base classes with non-default constructors. Such is life.
In the designer for this form, show the properties of the form, and change to the Events view (the lightening bolt icon). Double-click on the FormClosing event. That will add this code for a ShowHideWindowBase_FormClosing handler to your base class. Change it so it looks like this.
private void ShowHideWindowBase_FormClosing(object sender, FormClosingEventArgs e)
{
Debug.Assert(Manager != null); //Make sure that SetManager was called
e.Cancel = true;
Manager.HideAll();
}
The e.Cancel=true; says "I know someone tried to close this form, don't let it close". Instead, we'll cause all the sub forms to be hidden including this one.
That class is done. Now let's do the manager class.
The Manager
Create a new class in your project name ShowHideFormManager. Use this code:
public class ShowHideFormManager
{
private Dictionary<string, ShowHideFormBase> _forms = new Dictionary<string, ShowHideFormBase>();
private Form _mainForm;
public ShowHideFormManager(Form mainForm)
{
_mainForm = mainForm;
}
// This will add a sub form to be managed
public void Add(string windowsName, ShowHideFormBase form)
{
_forms.Add(windowsName, form);
}
// This will hide all managed sub forms and show the main form
public void HideAll()
{
_mainForm.Show();
foreach (var formPair in _forms)
{
formPair.Value.Hide();
}
}
// this will hide the main form and show the named sub form
public void Show(string formToShowName)
{
_mainForm.Hide();
foreach (var formPair in _forms)
{
if (formPair.Key != formToShowName)
{
formPair.Value.Hide();
}
}
if (_forms.TryGetValue(formToShowName, out var formToShow))
{
formToShow.Show();
}
}
}
Note that the shiny new wheel is up to about 75 or 80 lines of code.
The Application's Main Form
I'm assuming that you have a form named Form1 in your application (the one that gets created when you create your application.
Add this private field:
private ShowHideFormManager _manager = null;
and this public method:
public void SetManager(ShowHideFormManager manager)
{
_manager = manager;
}
Drop three buttons on the main form, set their Name properties to "SubForm1Btn", "SubForm2Btn", and "SubForm3Btn" and set the Text properties to something useful. In the click handlers do something like this for each button:
private void SubForm1Btn_Click(object sender, EventArgs e)
{
_manager.Show("Sub Form 1");
}
changing the numbers, obviously
The Sub Forms
Now create three new forms in your project. Name the classes SubForm1, SubForm2 and SubForm3.
Note, I create three sub forms, not 4 - creating the fourth would be easy
Open the code view for each form. The only change we are going to make to these three forms is to change the class declaration and constructor to:
public partial class SubForm1 : ShowHideFormBase
{
public SubForm1(ShowHideFormManager manager)
{
InitializeComponent();
SetManager(manager);
}
}
For all three forms: 1, 2, and 3, obviously
This changes the base class from Form to ShowHideFormBase. It also makes it so each of these forms must be initialized with a ShowHideFormManager instance, and we call SetManager (which is a base class method) to initialize the form with the manager.
Finally, changes to Program.cs
Finally, we'll make some minor changes to the Main method in Program.cs. These changes:
Create the Manager
Instantiate the main form as well as the three sub forms.
And call the normal Application.Run method
Here's the new Main method:
[STAThread]
static void Main()
{
Application.EnableVisualStyles();
Application.SetCompatibleTextRenderingDefault(false);
var mainForm = new Form1();
var manager = new ShowHideFormManager(mainForm);
mainForm.SetManager(manager);
var subForm1 = new SubForm1(manager);
var subForm2 = new SubForm2(manager);
var subForm3 = new SubForm3(manager);
manager.Add("Sub Form 1", subForm1);
manager.Add("Sub Form 2", subForm2);
manager.Add("Sub Form 3", subForm3);
Application.Run(mainForm);
}
Important: The strings you use in the manager.Add call (e.g. "Sub Form 1") must exactly match the string you pass in each of the calls to _manager.Show("Sub Form 1"); in the button handlers. When I finished this, I decided that I should have used an enum, but everything was working.
How it Works
Press F5 and the main form (with three buttons on it) should pop up. Press any of the buttons and the corresponding form will pop up (and the main form will hide). Close the sub form, and the main form will re-open letting you press that button again or another button.
While you are looking at this, notice that there are almost no changes to the Main Form or the Sub Forms. The magic is all in the form base class and the manager class. You can do whatever you want with any of the forms (as long as you get those minimal changes in the right places.

Why does deadlock occur in this specific WinForms app?

I create a simple Windows Form with a text box, and Set button and a Toggle button. When I click the Toggle button, a thread is created setting text to the text box repeatedly. When I click the button again, the thread stops. When I click the Set button, a text is set to the text box once. Deadlock occurs if I do the following:
Run the app (in debug mode).
Click the Toggle button to let text run in the text box.
Click Set button. -> Deadlock occurs in this step.
Can you explain why and how deadlock occurs in this situation? How to avoid it?
Below is the code:
using System;
using System.Collections.Generic;
using System.Linq;
using System.Windows.Forms;
namespace DeadLockTest
{
static class Program
{
/// <summary>
/// The main entry point for the application.
/// </summary>
[STAThread]
static void Main()
{
Application.EnableVisualStyles();
Application.SetCompatibleTextRenderingDefault(false);
Application.Run(new Form1());
}
}
}
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading;
using System.Windows.Forms;
namespace DeadLockTest
{
public class Form1 : Form
{
private System.Windows.Forms.TextBox textBox1;
private System.Windows.Forms.Button button1;
private System.Windows.Forms.Button button2;
private int counter;
private Thread thread;
private bool cancelRequested;
private string content;
private object lockKey = new object();
public Form1()
{
InitializeComponent();
}
protected void UpdateContent()
{
this.textBox1.Text = this.content;
}
protected void InvokeUpdateContent()
{
lock (this.lockKey)
{
if (InvokeRequired)
{
Invoke(new Action(UpdateContent));
}
else
{
UpdateContent();
}
}
}
protected void SetText(string text)
{
this.content = text;
InvokeUpdateContent();
}
protected void StressTest()
{
int localCounter = 0;
while (!this.cancelRequested)
{
SetText(string.Format("{0}", localCounter++));
}
this.cancelRequested = false;
this.thread = null;
}
private void InitializeComponent()
{
this.textBox1 = new System.Windows.Forms.TextBox();
this.button1 = new System.Windows.Forms.Button();
this.button2 = new System.Windows.Forms.Button();
this.SuspendLayout();
//
// textBox1
//
this.textBox1.Anchor = ((System.Windows.Forms.AnchorStyles)(((System.Windows.Forms.AnchorStyles.Top | System.Windows.Forms.AnchorStyles.Left)
| System.Windows.Forms.AnchorStyles.Right)));
this.textBox1.Location = new System.Drawing.Point(12, 12);
this.textBox1.Name = "textBox1";
this.textBox1.ReadOnly = true;
this.textBox1.Size = new System.Drawing.Size(260, 20);
this.textBox1.TabIndex = 0;
//
// button1
//
this.button1.Location = new System.Drawing.Point(12, 38);
this.button1.Name = "button1";
this.button1.Size = new System.Drawing.Size(75, 23);
this.button1.TabIndex = 1;
this.button1.Text = "Set";
this.button1.UseVisualStyleBackColor = true;
this.button1.Click += new System.EventHandler(this.button1_Click);
//
// button2
//
this.button2.Location = new System.Drawing.Point(93, 38);
this.button2.Name = "button2";
this.button2.Size = new System.Drawing.Size(75, 23);
this.button2.TabIndex = 2;
this.button2.Text = "Toggle";
this.button2.UseVisualStyleBackColor = true;
this.button2.Click += new System.EventHandler(this.button2_Click);
//
// Form1
//
this.AutoScaleDimensions = new System.Drawing.SizeF(6F, 13F);
this.AutoScaleMode = System.Windows.Forms.AutoScaleMode.Font;
this.ClientSize = new System.Drawing.Size(284, 262);
this.Controls.Add(this.button2);
this.Controls.Add(this.button1);
this.Controls.Add(this.textBox1);
this.Name = "Form1";
this.Text = "Form1";
this.ResumeLayout(false);
this.PerformLayout();
}
private void button1_Click(object sender, EventArgs e)
{
SetText(string.Format("{0}", this.counter++));
}
private void button2_Click(object sender, EventArgs e)
{
if (this.thread == null)
{
this.thread = new Thread(new ThreadStart(StressTest));
thread.Start();
}
else
{
this.cancelRequested = true;
}
}
}
}

Can you explain why and how deadlock occurs in this situation?
Sure...the deadlock occurs because of the lock()/Invoke() combination.
While the secondary thread is running and updating, it obtains a lock on the object. Then the secondary thread calls Invoke(), which is a synchronous call. It is key to realize that the secondary thread actually waits for the main UI thread to update the TextBox before continuing.
When you click the Set button, it attempts to update but must wait for the lock to be released by the secondary thread. At this point the main UI actually stops and freezes at the lock() line waiting for the secondary thread to release the lock. While waiting for the lock to be released, the main UI thread cannot process any messages.
But what is the secondary thread doing? It currently has the lock and is waiting for the main UI thread to service its synchronous Invoke() call. Since the main UI thread is waiting for the lock to be released, though, it cannot service any requests (including Invoke() requests) and bam...DEADLOCK! They are both waiting for each other.
How to avoid it?
Never use lock() from the main UI thread. In some scenarios, switching from Invoke() to BeginInvoke() can solve the problem since BeginInvoke() is asynchronous.

InvalidOperationalException base.Dispose(disposing)

I creating diagnostic application for PLCs. I have one form and a few Controls, which was inherited of UserControl. This Controls I switch. One view is Dashboard, Graph, and so on. When the graph is running, exception is occured. Exception is showed on line "base.Dispose(disposing)" in Form1.Designer.cs. Do you have any idea, how I can fix it? Thanks for any ideas.
This is code of Form1.Designer.cs. Error is show on line base.Dispose(disposing). Basicaly I don't know what this part of code do. That I can't repair it. Can somebody tell me, how it works? When is this part called? I don't find any use of method Dispose() in my program, only override methodes in each Control (inherited from UserControl). Thanks
namespace WindowsFormsApplication1
{
partial class Form1
{
///
/// Required designer variable.
///
private System.ComponentModel.IContainer 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)
{
/*Updated 8.4.2013*/
//try
//{
if (disposing && (components != null))
{
components.Dispose();
}
base.Dispose(disposing);
//}
//catch { }
}
#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 InitializeComponent()
{
System.ComponentModel.ComponentResourceManager resources = new System.ComponentModel.ComponentResourceManager(typeof(Form1));
this.statusStrip1 = new System.Windows.Forms.StatusStrip();
this.toolStripStatusLabel1 = new System.Windows.Forms.ToolStripStatusLabel();
this.btn_ChangeLanguage = new System.Windows.Forms.Button();
this.pictureBox1 = new System.Windows.Forms.PictureBox();
this.Zobraz_Palubka = new System.Windows.Forms.Button();
this.Zobraz_Verzi = new System.Windows.Forms.Button();
this.Zobraz_error = new System.Windows.Forms.Button();
this.Zobraz_Nastaveni = new System.Windows.Forms.Button();
this.Zobraz_TestIO = new System.Windows.Forms.Button();
this.Zobraz_monitor = new System.Windows.Forms.Button();
this.statusStrip1.SuspendLayout();
((System.ComponentModel.ISupportInitialize)(this.pictureBox1)).BeginInit();
this.SuspendLayout();
//
// statusStrip1
//
this.statusStrip1.Items.AddRange(new System.Windows.Forms.ToolStripItem[] {
this.toolStripStatusLabel1});
resources.ApplyResources(this.statusStrip1, "statusStrip1");
this.statusStrip1.Name = "statusStrip1";
//
// toolStripStatusLabel1
//
this.toolStripStatusLabel1.Name = "toolStripStatusLabel1";
resources.ApplyResources(this.toolStripStatusLabel1, "toolStripStatusLabel1");
//
// btn_ChangeLanguage
//
this.btn_ChangeLanguage.Image = global::WindowsFormsApplication1.Properties.Resources.flag_cze_mini;
resources.ApplyResources(this.btn_ChangeLanguage, "btn_ChangeLanguage");
this.btn_ChangeLanguage.Name = "btn_ChangeLanguage";
this.btn_ChangeLanguage.UseVisualStyleBackColor = true;
this.btn_ChangeLanguage.Click += new System.EventHandler(this.btn_ChangeLanguage_Click);
this.btn_ChangeLanguage.MouseEnter += new System.EventHandler(this.Zobraz_Nastaveni_MouseEnter);
this.btn_ChangeLanguage.MouseLeave += new System.EventHandler(this.Zobraz_Nastaveni_MouseLeave);
//
// pictureBox1
//
this.pictureBox1.BackColor = System.Drawing.Color.Transparent;
this.pictureBox1.Image = global::WindowsFormsApplication1.Properties.Resources.trojuhelnik;
resources.ApplyResources(this.pictureBox1, "pictureBox1");
this.pictureBox1.Name = "pictureBox1";
this.pictureBox1.TabStop = false;
//
// Zobraz_Palubka
//
this.Zobraz_Palubka.Image = global::WindowsFormsApplication1.Properties.Resources.tachometr_mini;
resources.ApplyResources(this.Zobraz_Palubka, "Zobraz_Palubka");
this.Zobraz_Palubka.Name = "Zobraz_Palubka";
this.Zobraz_Palubka.UseVisualStyleBackColor = true;
this.Zobraz_Palubka.Click += new System.EventHandler(this.Zobraz_Click);
this.Zobraz_Palubka.MouseEnter += new System.EventHandler(this.Zobraz_Nastaveni_MouseEnter);
this.Zobraz_Palubka.MouseLeave += new System.EventHandler(this.Zobraz_Nastaveni_MouseLeave);
//
// Zobraz_Verzi
//
this.Zobraz_Verzi.Image = global::WindowsFormsApplication1.Properties.Resources.info_mini;
resources.ApplyResources(this.Zobraz_Verzi, "Zobraz_Verzi");
this.Zobraz_Verzi.Name = "Zobraz_Verzi";
this.Zobraz_Verzi.UseVisualStyleBackColor = true;
this.Zobraz_Verzi.Click += new System.EventHandler(this.Zobraz_Click);
this.Zobraz_Verzi.MouseEnter += new System.EventHandler(this.Zobraz_Nastaveni_MouseEnter);
this.Zobraz_Verzi.MouseLeave += new System.EventHandler(this.Zobraz_Nastaveni_MouseLeave);
//
// Zobraz_error
//
this.Zobraz_error.Image = global::WindowsFormsApplication1.Properties.Resources.error1_mini;
resources.ApplyResources(this.Zobraz_error, "Zobraz_error");
this.Zobraz_error.Name = "Zobraz_error";
this.Zobraz_error.UseVisualStyleBackColor = true;
this.Zobraz_error.Click += new System.EventHandler(this.Zobraz_Click);
this.Zobraz_error.MouseEnter += new System.EventHandler(this.Zobraz_Nastaveni_MouseEnter);
this.Zobraz_error.MouseLeave += new System.EventHandler(this.Zobraz_Nastaveni_MouseLeave);
//
// Zobraz_Nastaveni
//
this.Zobraz_Nastaveni.Image = global::WindowsFormsApplication1.Properties.Resources.settings_mini;
resources.ApplyResources(this.Zobraz_Nastaveni, "Zobraz_Nastaveni");
this.Zobraz_Nastaveni.Name = "Zobraz_Nastaveni";
this.Zobraz_Nastaveni.UseVisualStyleBackColor = true;
this.Zobraz_Nastaveni.Click += new System.EventHandler(this.Zobraz_Click);
this.Zobraz_Nastaveni.MouseEnter += new System.EventHandler(this.Zobraz_Nastaveni_MouseEnter);
this.Zobraz_Nastaveni.MouseLeave += new System.EventHandler(this.Zobraz_Nastaveni_MouseLeave);
//
// Zobraz_TestIO
//
this.Zobraz_TestIO.Image = global::WindowsFormsApplication1.Properties.Resources.testIO_mini;
resources.ApplyResources(this.Zobraz_TestIO, "Zobraz_TestIO");
this.Zobraz_TestIO.Name = "Zobraz_TestIO";
this.Zobraz_TestIO.UseVisualStyleBackColor = true;
this.Zobraz_TestIO.Click += new System.EventHandler(this.Zobraz_Click);
this.Zobraz_TestIO.MouseEnter += new System.EventHandler(this.Zobraz_Nastaveni_MouseEnter);
this.Zobraz_TestIO.MouseLeave += new System.EventHandler(this.Zobraz_Nastaveni_MouseLeave);
//
// Zobraz_monitor
//
this.Zobraz_monitor.Image = global::WindowsFormsApplication1.Properties.Resources.line_graph_icon_mini;
resources.ApplyResources(this.Zobraz_monitor, "Zobraz_monitor");
this.Zobraz_monitor.Name = "Zobraz_monitor";
this.Zobraz_monitor.UseVisualStyleBackColor = true;
this.Zobraz_monitor.Click += new System.EventHandler(this.Zobraz_Click);
this.Zobraz_monitor.MouseEnter += new System.EventHandler(this.Zobraz_Nastaveni_MouseEnter);
this.Zobraz_monitor.MouseLeave += new System.EventHandler(this.Zobraz_Nastaveni_MouseLeave);
//
// Form1
//
resources.ApplyResources(this, "$this");
this.AutoScaleMode = System.Windows.Forms.AutoScaleMode.Font;
this.Controls.Add(this.btn_ChangeLanguage);
this.Controls.Add(this.pictureBox1);
this.Controls.Add(this.Zobraz_Palubka);
this.Controls.Add(this.Zobraz_Verzi);
this.Controls.Add(this.Zobraz_error);
this.Controls.Add(this.statusStrip1);
this.Controls.Add(this.Zobraz_Nastaveni);
this.Controls.Add(this.Zobraz_TestIO);
this.Controls.Add(this.Zobraz_monitor);
this.Name = "Form1";
this.statusStrip1.ResumeLayout(false);
this.statusStrip1.PerformLayout();
((System.ComponentModel.ISupportInitialize)(this.pictureBox1)).EndInit();
this.ResumeLayout(false);
this.PerformLayout();
}
#endregion
private System.Windows.Forms.Button Zobraz_monitor;
private System.Windows.Forms.Button Zobraz_Nastaveni;
private System.Windows.Forms.StatusStrip statusStrip1;
private System.Windows.Forms.ToolStripStatusLabel toolStripStatusLabel1;
private System.Windows.Forms.Button Zobraz_TestIO;
private System.Windows.Forms.Button Zobraz_error;
private System.Windows.Forms.Button Zobraz_Verzi;
private System.Windows.Forms.Button Zobraz_Palubka;
private System.Windows.Forms.PictureBox pictureBox1;
private System.Windows.Forms.Button btn_ChangeLanguage;
}
}
Here is exception detail:
System.InvalidOperationException was unhandled by user code
Message=Cross-thread operation not valid: Control 'Form1' accessed from a thread other than the thread it was created on.
Source=System.Windows.Forms
StackTrace:
at System.Windows.Forms.Control.get_Handle()
at System.Windows.Forms.Form.UpdateMenuHandles(MainMenu menu, Boolean forceRedraw)
at System.Windows.Forms.Form.UpdateMenuHandles()
at System.Windows.Forms.Form.MenuChanged(Int32 change, Menu menu)
at System.Windows.Forms.Form.Dispose(Boolean disposing)
at WindowsFormsApplication1.Form1.Dispose(Boolean disposing) in c:__Projects__\C#\RailJay Diagnostic SW\20130408\Motor\Motor\Form1.Designer.cs:line 23
at System.ComponentModel.Component.Dispose()
at System.Windows.Forms.ApplicationContext.Dispose(Boolean disposing)
at System.Windows.Forms.Application.ThreadContext.DisposeThreadWindows()
InnerException:

It appears that you're calling Dispose from a thread other than the GUI thread. You can't do that.

You need to be more specific - perhaps adding some code to what you are trying to do, where?
[EDIT]
As Jim mentioned, you are referencing a form from a seperate thread;
Here is exception detail:
System.InvalidOperationException was unhandled by user code
Message=Cross-thread operation not valid: Control 'Form1' accessed
from a thread other than the thread it was created on
This means that you are trying to dispose Form1 from a thread that it was not created on.
Have you got sperate threads running in the application, if so, this is the first place to look.
Are you closing the Form1 anywhere within code?

c# call button event that is on another winform

i want when i click on button1 on form1 to call button2 that is on form2 and execute the code that is under button2 event.
The following code won't work:
button2.PerformClick();
The error i get is "button2 does not exist in current context", so i tried to set modifiers to public, also click event to set on public void... no luck.
form2.button2.PerformClick(); also doesn't work.

You should put the code that you want to call into a public method on Form2 and then call that method from form1.
If you need a specific instance of form2 to call the method from then you could store the Handle property from form2 somewhere and then get the appropriate form as follows.
var myForm = Form.FromHandle(myForm2Handle);
myForm.MyPublicMethod();
You could then call this from the Button1 click event.

You've got an architecture problem if you're reaching between forms and executing button click event code. You should really have an event system in place for this.
I'd suggest that Form2 would have a listener set up for an event on Form1:
public class Form2{
public Form2{
// get your form instance
Form1 MyForm1Instance = new Form1();
// hook up the event
MyForm1Instance.SomeEvent += new EventHandler(MyHandler);
}
public void MyHandler(){
// handle event here; run your button_click code or whatever
}
}
...and Form1 would simply need to fire "SomeEvent" when you click the appropriate button.

try this and see if it works, it works for me.
in the first form create your method
public void DoSomething(parameters)
{
//code to handle those parameters
}
in the calling or second form use this in the event you want to call form1 from
Form1 f1 = new Form1();
try
{
f1.DoSomething(arguments);
}
catch (Exception)
{
catch the exceptions
}
f1.Show();
comment if it works for u and mark it as an answer.

I think your problem is that you are trying to call instance method without object creation. Here is sample code to demostrate to you possible way of method calling:
using System;
using System.Collections.Generic;
using System.Linq;
using System.Windows.Forms;
namespace WindowsFormsApplication1
{
static class Program
{
/// <summary>
/// The main entry point for the application.
/// </summary>
[STAThread]
static void Main()
{
Application.EnableVisualStyles();
Application.Run(new TestForm1());
}
}
public partial class TestForm1 : Form
{
private System.Windows.Forms.Button button1;
public void button1_Click(object sender, EventArgs e)
{
MessageBox.Show("Hello! Im TestForm1 and Im going to call TestForm2's code!");
// You must create TestForm2 because of button1_Click is not a static method!!!
TestForm2 form2 = new TestForm2();
form2.button1_Click(this, new EventArgs());
}
public TestForm1()
{
this.button1 = new System.Windows.Forms.Button();
this.SuspendLayout();
//
// button1
//
this.button1.Location = new System.Drawing.Point(12, 12);
this.button1.Name = "button1";
this.button1.Size = new System.Drawing.Size(88, 23);
this.button1.TabIndex = 0;
this.button1.Text = "button1";
this.button1.UseVisualStyleBackColor = true;
this.button1.Click += new System.EventHandler(this.button1_Click);
this.Controls.Add(this.button1);
this.Name = "TestForm1";
this.Text = "TestForm1";
this.ResumeLayout(false);
}
}
public partial class TestForm2 : Form
{
private System.Windows.Forms.Button button1;
public void button1_Click(object sender, EventArgs e)
{
MessageBox.Show("Hello! Im TestForm2");
}
public TestForm2()
{
this.button1 = new System.Windows.Forms.Button();
this.SuspendLayout();
//
// button1
//
this.button1.Location = new System.Drawing.Point(12, 12);
this.button1.Name = "button1";
this.button1.Size = new System.Drawing.Size(88, 23);
this.button1.TabIndex = 0;
this.button1.Text = "button1";
this.button1.UseVisualStyleBackColor = true;
this.button1.Click += new System.EventHandler(this.button1_Click);
this.Controls.Add(this.button1);
this.Name = "TestForm2";
this.Text = "TestForm2";
this.ResumeLayout(false);
}
}
}

Cannot access a disposed object

Cannot access a disposed object
Anyone know why I would get this error "Cannot access a disposed object" on this line of code
Invoke(new UpdateTimerDelegate(UpdateTimer), new object[] { null });
Hit start over then either accept / reject / or close the form -- seems to happen when closing the form
the error happens when you bring the form up again
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
namespace TimerTester
{
public class Form1 : Form
{
public Form1()
{
InitializeComponent();
}
private void StartOverBtn_Click(object sender, EventArgs e)
{
ShowForm2();
}
private void Form1_Load(object sender, EventArgs e)
{
ShowForm2();
}
private void ShowForm2()
{
Form2 f2;
f2 = new Form2(10000);
f2.Owner = this;
switch (f2.ShowDialog())
{
case DialogResult.Yes:
break;
case DialogResult.No:
break;
default:
break;
}
}
/// <summary>
/// Required designer variable.
/// </summary>
private System.ComponentModel.IContainer 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.Dispose();
}
base.Dispose(disposing);
}
#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 InitializeComponent()
{
this.StartOverBtn = new System.Windows.Forms.Button();
this.SuspendLayout();
//
// StartOverBtn
//
this.StartOverBtn.Location = new System.Drawing.Point(33, 33);
this.StartOverBtn.Name = "StartOverBtn";
this.StartOverBtn.Size = new System.Drawing.Size(75, 23);
this.StartOverBtn.TabIndex = 0;
this.StartOverBtn.Text = "Start Over";
this.StartOverBtn.UseVisualStyleBackColor = true;
this.StartOverBtn.Click += new System.EventHandler(this.StartOverBtn_Click);
//
// Form1
//
this.AutoScaleDimensions = new System.Drawing.SizeF(6F, 13F);
this.AutoScaleMode = System.Windows.Forms.AutoScaleMode.Font;
this.ClientSize = new System.Drawing.Size(292, 266);
this.Controls.Add(this.StartOverBtn);
this.Name = "Form1";
this.Text = "Form1";
this.Load += new System.EventHandler(this.Form1_Load);
this.ResumeLayout(false);
}
#endregion
private System.Windows.Forms.Button StartOverBtn;
}
}
form2
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
using System.Diagnostics;
namespace TimerTester
{
public class Form2 : Form
{
public Form2(int timeoutSecondsForAcceptCall)
{
this.timeoutSecondsForAcceptCall = timeoutSecondsForAcceptCall;
InitializeComponent();
tUpdateTimer = new System.Threading.Timer(new System.Threading.TimerCallback(UpdateTimer), null, TimeSpan.FromSeconds(1), TimeSpan.FromSeconds(1));
}
DateTime dtCreate = DateTime.Now;
int timeoutSecondsForAcceptCall = 99999;
System.Threading.Timer tUpdateTimer;
private delegate void UpdateTimerDelegate(object obj);
void UpdateTimer(object obj)
{
if (InvokeRequired == true)
{
Invoke(new UpdateTimerDelegate(UpdateTimer), new object[] { null });
}
else
{
TimeSpan ts = DateTime.Now - dtCreate;
if (ts.TotalSeconds > timeoutSecondsForAcceptCall)
{
DialogResult = DialogResult.Cancel;
return;
}
TimeSpan timeleft = TimeSpan.FromSeconds(timeoutSecondsForAcceptCall) - ts;
label1.Text = FormatTimeSpan(timeleft);
}
}
private string FormatTimeSpan(TimeSpan ts)
{
return ((int)ts.TotalMinutes).ToString().PadLeft(2, '0') + ":" + ((int)ts.Seconds).ToString().PadLeft(2, '0');
}
private void btnAccept_Click(object sender, EventArgs e)
{
DialogResult = DialogResult.Yes;
}
private void btnReject_Click(object sender, EventArgs e)
{
DialogResult = DialogResult.No;
}
/// <summary>
/// Required designer variable.
/// </summary>
private System.ComponentModel.IContainer 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.Dispose();
}
base.Dispose(disposing);
}
#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 InitializeComponent()
{
this.btnAccept = new System.Windows.Forms.Button();
this.btnReject = new System.Windows.Forms.Button();
this.label1 = new System.Windows.Forms.Label();
this.SuspendLayout();
//
// btnAccept
//
this.btnAccept.Location = new System.Drawing.Point(31, 30);
this.btnAccept.Name = "btnAccept";
this.btnAccept.Size = new System.Drawing.Size(75, 23);
this.btnAccept.TabIndex = 0;
this.btnAccept.Text = "Accept";
this.btnAccept.UseVisualStyleBackColor = true;
this.btnAccept.Click += new System.EventHandler(this.btnAccept_Click);
//
// btnReject
//
this.btnReject.Location = new System.Drawing.Point(140, 29);
this.btnReject.Name = "btnReject";
this.btnReject.Size = new System.Drawing.Size(75, 23);
this.btnReject.TabIndex = 1;
this.btnReject.Text = "Reject";
this.btnReject.UseVisualStyleBackColor = true;
this.btnReject.Click += new System.EventHandler(this.btnReject_Click);
//
// label1
//
this.label1.AutoSize = true;
this.label1.Location = new System.Drawing.Point(31, 80);
this.label1.Name = "label1";
this.label1.Size = new System.Drawing.Size(35, 13);
this.label1.TabIndex = 2;
this.label1.Text = "label1";
//
// Form2
//
this.AutoScaleDimensions = new System.Drawing.SizeF(6F, 13F);
this.AutoScaleMode = System.Windows.Forms.AutoScaleMode.Font;
this.ClientSize = new System.Drawing.Size(240, 117);
this.Controls.Add(this.label1);
this.Controls.Add(this.btnReject);
this.Controls.Add(this.btnAccept);
this.Name = "Form2";
this.Text = "Form2";
this.ResumeLayout(false);
this.PerformLayout();
}
#endregion
private System.Windows.Forms.Button btnAccept;
private System.Windows.Forms.Button btnReject;
private System.Windows.Forms.Label label1;
}
}

Your form is disposed by the time invoke() message is processed by the message loop. I donot think so there is a way to avoid it. You can put a check e.g
if(!yourForm.IsDisposed)
yourForm.Invoke(...)
But that may not work sometime as the invoke is posted to UI thread and by the time it is process form may already be disposed and you will still get that exception. You have to fix your program in a way to avoid this situation by making sure invoke is not posted on a disposed or disposing form. This is a fatal error and your program will exit after this. I think suppressing it via try{}catch{} will not work as framework already start to unload when catch block is executed.
You can fix the problem in two ways.
1. Just drop a timer component from toolbox i.e. System.Windows.Forms.Timer and use that.
Designer will automatically add it to component collection and dispose it before form is disposed.
2. Manually over OnDispose(bool disposing) in your form and perform
if(disposing)
yourTimer.Dispose()
So now your timer is dispose before your form so no subsequent invoke() will be posted to your form after its disposed.

You see this error, because your System.Threading.Timer is not component of form. Thus it doesn't get disposed when form is closed. I'd recommend you to use System.Windows.Forms.Timer instead. Because this is a component, which you can place on your Form and it will be disposed with other form's components (just drag it from toolbox in designer).
public class Form2 : Form
{
DateTime dtCreate = DateTime.Now;
int timeoutSecondsForAcceptCall = 99999;
public Form2(int timeoutSecondsForAcceptCall)
{
this.timeoutSecondsForAcceptCall = timeoutSecondsForAcceptCall;
InitializeComponent();
timer1.Interval = 1000;
timer1.Start();
}
private void timer1_Tick(object sender, EventArgs e)
{
TimeSpan ts = DateTime.Now - dtCreate;
if (ts.TotalSeconds > timeoutSecondsForAcceptCall)
{
DialogResult = DialogResult.Cancel;
return;
}
TimeSpan timeleft = TimeSpan.FromSeconds(timeoutSecondsForAcceptCall) - ts;
label1.Text = FormatTimeSpan(timeleft);
}
// other code
}
BTW another benefit of using System.Windows.Forms.Timer is that it's Tick event handler executed on UI thread. Thus you don't need to verify if invoke required.

I've had this problem before. There are a couple things you should be doing.
1) When you close your program, you should be removing handlers and/or shutting down timers or other code that will run as the program is exiting. You are still left with the problem of how many timer handlers will still run after shutting down the timer. One possible solution is to set a "stop running" flag after you turn off the Timer. Check the flag in the handler and don't run the code if it is set. The flag could be a bool marked as volatile or a long using Interlocked to avoid concurrency issues, especially if your timer is really short.
2) Wrap a try/catch around your Invoke statement, also put one in the GUI editing code (the part where InvokeRequired == false).