Closing of all Previous Forms and Opening of New Form in C#

Question

How to Close background Forms whenever a new form is opened in Windows Forms C#? It should not be the specific form to be closed..... It should close all the background forms whenever a form is opened.... If there's a solution or link please send me......

Amit Gupta · Answer

@Sourav If you want to hide your main form as well then you can use @Rama's solution. Your whole code will look like this private void btnOpenForm_Click( object sender, EventArgs e) { Form form = new Form(); form.FormClosed += delegate { //this.Close(); // if you want to open the main form then comment the above line // and uncomment the below line this .Show(); form = null ; }; this .Hide(); form.Show(); form.Activate(); } Change above code to suit your needs

Amit Gupta · Answer

Hey As Application.OpenForms is readonly collection and cannot be modified using foreach iteration, use for loop instead. Your code will look like below private void btnOpenForm_Click( object sender, EventArgs e) { CloseAllForm(); Form form = new Form(); form.Show(); } void CloseAllForm() { for ( int x = 0; x { if (Application.OpenForms[x] != this ) Application.OpenForms[x].Close(); } } Good Luck !!

Rama Krishna · Answer

Hi amit, I think it's not better Idea because every time he has to loop and then hide Instead he could try what I provided

Amit Gupta · Answer

Hi Rama Loop will only execute when it has any opened form. However, to achieve a task there aee many ways. He can apply any of the solution.

Amit Gupta · Answer

Call that load method before opening a new form.

Amit Gupta · Answer

Create a function and write that code under that and whenever you are opening a form, just call that function.

Rama Krishna · Answer

Hi Sourav, 1. First hide your current form this.Hide(); 2. Second initialize your new form NewForm form = new NewForm (); 3. Third use below line form.Closed += (s, args) => this.Close(); 4. Finally use below line form.Show(); Entire code looks like below this.Hide(); NewForm form = new NewForm(); form.Closed += (s, args) => this.Close(); form.Show();

Amit Gupta · Answer

Try this foreach (Form f in Application.OpenForms) f Close();

Gaurav Gahlot · Answer

@ Sreekanth form.Closed += (s, args) => this .Close(); This line of code binds an anonymous method with the Closed event of form . So, when the closed event will be raised or triggered, this method will handle that event.

Sreekanth Reddy · Answer

I found the below solution in stack overflow : https://stackoverflow.com/questions/9029351/close-all-open-forms-except-the-main-menu-in-c-sharp List openForms = new List (); foreach (Form f in Application.OpenForms) openForms.Add(f); foreach (Form f in openForms) { if (f.Name != "Menu") f.Close(); } Or you can use a for loop: for (int i = Application.OpenForms.Count - 1; i >= 0; i--) { if (Application.OpenForms[i].Name != "Menu") Application.OpenForms[i].Close(); }

Sreekanth Reddy · Answer

@Rama Krishna Can I know. What the below line refers to which you had stated ? form.Closed += (s, args) => this.Close();

Gaurav Gahlot · Answer

Hi Sourav! You are getting an error, because you are modifying the collection that you are currently itterating on. So, this is surely not going to work. Take a note of the following points: closing Form1 , which the main form in your case, will close the application you should not close Form1 , rather hide it How to hide? As rightly pointed by @Rama, you should not itterate over the OpenForms because it is not efficient. So, you can do somethng like: private void btnNewForm_Click( object sender, EventArgs e) { // hide the current form, Form1 this .Hide(); var newForm = new Form2(); newForm.Show(); } This should solve, your errors. However, the solution might wary based on your usecase. I hope this helps. Thank you!

Dorababu Meka · Answer

Try this code List openForms = new List (); foreach (Form f in Application.OpenForms) openForms.Add(f); foreach (Form f in openForms) { f.Close(); } Or Form[] forms = Application.OpenForms.Cast ().ToArray(); foreach (Form thisForm in forms) { thisForm.Close(); }

EMEKE JOSHUA · Answer

private void btnNewForm_Click( object sender, EventArgs e) { Form newForm = new Form(); this .Hide(); newForm.Show(); }

Sourav Kumar Das · Answer

using MDI technique If there's a solution please send me the link.....

Sourav Kumar Das · Answer

But we are only closing specific form at your given solution.... Because if it implements in MDI form in which it has multiple forms, so at that time how i can use it.. @Amit Gupta

Sourav Kumar Das · Answer

I accept your previous solution but the background form is not closing. @Amit Gupta

Sourav Kumar Das · Answer

It's Showing same error...@Amit Gupta

Amit Gupta · Answer

load(); Form2 frm = new Form2(); frm.Show(); // Put your load body under try catch

Sourav Kumar Das · Answer

Can you ellaborate it...at which part I should place that load function. @Amit Gupta

Sourav Kumar Das · Answer

But I should not specify that this form should be closed at background whenever i open a new form at foreground...@Rama Krishna

Sourav Kumar Das · Answer

public partial class Form1 : Form { public Form1() { InitializeComponent(); } private void button1_Click(object sender, EventArgs e) { Form2 frm = new Form2(); frm.Show(); load(); } private void load() { foreach (Form f in Application.OpenForms) f.Close(); } Like this way..... But it showing error... @Amit Gupta

Sourav Kumar Das · Answer

foreach (Form f in Application.OpenForms) f Close(); at where I should apply this one..@Amit Gupta