Using static variable and Activated Event for Building "Home" Button of Windows application

In this tutorial I will share experience how , just with the help of a few clicks and a few lines of code , to build a windows application with Home button, that allows to return to Home form (in fact to close all opened forms by one click) . The examples are written using C#.

In this tutorial I will share experience how, just with the help of a few clicks and a few lines of code, to build a windows application with "Home" button, that allows to return to "Home" form (in fact to close all opened forms by one click). The examples are written using C#.  

Before we jump into C# code we have to choose the best way to build solution of our Windows application.

(Thanks, thanks DOT.NET ! Now we have inheritance, user controls, and so on. And we must use that!).

I strongly recommend to include in our solution at least two projects with different "Output Type":

  • Output Type of the first project is "Windows Aplication" ; 
  • Output Type of the second project is "Class Library".

Before using any control in the first project, you have to create a control in the second project (for example, to create Button_C control that inherits from standard Button control ) and to use only controls from the second project on your forms.

This process takes no more than 20 seconds but advantage is obvious: at any time just for some seconds you can add to your control all that you want ( properties, events, color, and so on ). And just in seconds all addings and changes work on every your form (ten forms or hundred - it doesn't matter!).

Let's create our test project.

Step 1. Make a new solution named " WinProjects_Test".

Step 2. Add a "Windows Application" project named  "CloseForms".

Step 3. Add a "Windows Control Library" project named "CloseForms_Controls".

Step 4. Delete "UserControl1" from "CloseForms_Controls" project (we just don't need it).

Step 5. Add Windows Form named  "FormBasic" to "CloseForms_Controls" project. Change property BackColor to "Cornsilk" (just to see that it is our form with our BackColor).

Step 6. Build "CloseForms_Controls" project (right-click and select Build). After every changes it is recommended to rebuild the project !

Step 7. Build "CloseForms" project.

Step 8. To References of  "CloseForms" project add a reference to CloseForms_Controls.dll

(Right-click References of  "CloseForms" project, select Add Reference, from a tabbed dialog box select .NET Framework and with the help of "Browse ...". Find out the physical CloseForms_Controls.dll on the disk. Double-click CloseForms_Controls.dll to add it to the selected components list. Click OK to add this reference to the project).

Step 9. Rebuild solution.

Step 10. All our forms have to be inherited from FormBasic form. So far there is only one form in  our "CloseForms"  project : this is Form1. Open code of Form1, find out the line           

public class FormBasic : System.Windows.Forms.Form   

and change it to          

public class Form1 : CloseForms_Controls.FormBasic

Step 11. OK. Now our ship is ready for sailing off. We just have to  add a few forms and user controls to make our travel more interesting. Add Form2, Form3, Form4 to  "CloseForms" project and make them inherited from FormBasic. (To add inherited form to "CloseForms" project you can just right-click and select Add|Add Inherited Form ,then from Add New Item dialog box select Inherited Form and then from Inheritance Picker dialog box select our FormBasic).

Step 12. Add User Control , named Button_C, to CloseForms_Controls project. Open code of this control, find out line          

public class Button_C : System.Windows.Forms.UserControl

and change it to          

public class Button_C : Button

Now we have our own Button_C control with all properties, events of Button control. "To prove" that this is ours control let's change default property BackColor : double-click on Button_C.cs, right-click on the page (Button_C.cs[Design]) and select Properties, set BackColor to, for example, "AliceBlue". (Do you remember ?! After every changes it is recommended to rebuild the solution).

Step 13. Add one more User Control, named Buttons, to CloseForms_Controls project. Double-click on Button_C.cs, inside Toolbox click on "My User Controls" tab and drag and drop Button_C. Name it "button_CHome" with the text "Home". Drag and drop two more Button_C : button_CBack with the text "Back" and button_CNext with the text "Next". Pay attention ! We have created Buttons control with "Home" button. But, in fact, we could add "Home" button at any moment ("on demand" of the boss) without any serious problems (Don't forget to rebuild solution !).

Step 14. You should force to work buttons according to your desire on any form. With this purpose add to class Buttons three event Handlers:

#region "forClass"

public event EventHandler ClickNext;

public event EventHandler ClickBack;

public event EventHandler ClickHome;

#endregion

Open design of the Buttons.cs and double-click on the button_CNext button. Add the next code (to "private void button_CNext_Click"):

private void button_CNext_Click(object sender, System.EventArgs e)
{
          if (ClickNext != null
          {
                   ClickNext(this, e);
          }    
}

Similar "process" have to be done for the button_CBack and button_CHome controls:

private void button_CBack_Click(object sender, System.EventArgs e)

{

          if (ClickBack !=null)

          {

                   ClickBack(this,e);

          }

}


private void button_CHome_Click(object sender, System.EventArgs e)

{

          if (ClickHome !=null)

          {

                   ClickHome(this,e);

          }          

}

Our control is now ready to act.

And our solution you can see on Figure 1.

Fig_1.GIF

Figure 1.

Step 15. Now we can add some "actions" to our project. Inside CloseForms project from "My User Controls" tab drag and drop on every form Buttons control. Double-click on Form1.cs , right-click on Buttons1 control and select Properties, click "Events" button, double-click on "ClickBack", then - on "ClickHome", and then - on "ClickNext". Now Form1.cs code page has three new functions: buttons1_ClickBack, buttons1_ClickHome, buttons1_ClickNext.

Similar "clicks" have to be done for the Form2, Form3, Form4.

Step 16. Add a few lines of code to Form1.cs  code page (to above mentioned functions):

private void buttons1_ClickBack(object sender, System.EventArgs e)

{

          //Just to see that our ClickBack event can do something

          MessageBox.Show ("This is ClickBack. There is no any 'Back' way ! " +

          "We are on the Home Form ! ","CloseForms Project");

}

 

private  void buttons1_ClickHome(object sender, System.EventArgs e)

{

          //Just to see that our ClickHone event can do something

          MessageBox.Show ("This is ClickHome. There is no any 'Home' way ! " +

          "We are on the Home Form ! ","CloseForms Project");

}

 

private void buttons1_ClickNext(object sender, System.EventArgs e)

{

          //To open the next form ( in this case : Form2 )

          Form2  fOpen = new Form2 ();

          fOpen.ShowDialog ();

}

To Form2 (only for "buttons1_ClickNext"):

private void buttons1_ClickNext(object sender, System.EventArgs e)

{

          //To open the next form ( in this case : Form3 )

          Form3 fOpen = new Form3 ();

          fOpen.ShowDialog ();

}

To Form3 (only for "buttons1_ClickNext"):

private void buttons1_ClickNext(object sender, System.EventArgs e)

{

          //To open the next form ( in this case : Form4 )

          Form4 fOpen=new Form4();

          fOpen.ShowDialog ();

}

To Form4 (only for "buttons1_ClickNext"):

private void buttons1_ClickNext(object sender, System.EventArgs e)

{

          //To open the next form ( in this case : Form2 )

          Form2  fOpen = new Form2 ();

          fOpen.ShowDialog ();

}

Now you have possibilities to travel from form to form without any restrictions :

Form1-Form2-Form3-Form4-Form2-Form3-...

But ... only  forward ( not "backward and forward").

Step 17. In order to return "step by step" to the previous forms  add to Buttons.cs code page function "closeForm()"

private void closeForm()

{

          if (ParentForm.Name!= "Form1")

          {

                   ParentForm.Close ();

          }

}

and now add this function to "button_CBack_Click" :

private void button_CBack_Click(object sender, System.EventArgs e)

{

          if (ClickBack !=null)

          {

                   ClickBack(this,e);

                   closeForm ();

          }

}

Step 18. We closely have approached to our goal: there are tens (or may be hundreds) of opened forms and you should close all forms except for the Form1 (just to return to the "Home" form) by means only one click. OK ! We are going to do that by adding a few lines of code (without using collection of opened forms, and so on).

First of all you have to add some "command" to close all form. Certainly this command should be clear and visible for all forms. Let it be some variable : public static bool closeForms. Of course while  loading any form we have to command : "Don't close now !" (closeForms = false;). Well. While closing any form (I don't mean Form1) the previous one is activated . OK !

We can catch this and , if there is command " To close forms "  (closeForms = true;), we can close this form too ... and so on. And at last we should define who will give a command "Home". Of course it will be our "Buttons" control  and "button_CHome". Well, now we shall pass to action.

Double-click on FormBasic.cs, right-click on FormBasic[Design] and select Properties, click "Events" button, double-click on "Activated". 

Add to FormBasic.cs code page the next code :

#region "forClass"

public static bool closeForms ;//command to close all forms

#endregion

 

private void FormBasic_Load(object sender, System.EventArgs e)

{

          closeForms = false;//command : "Don't close now !"

          //just to inform where we are and to hide ControlBox

          if (this.Name != "Form1")

          {

                   this.Text = " My name is " + this.Name ;

                   this.ControlBox =false;

          }

          else

          {

                   this.Text = "Home Form. Where you would not sail you can " +

                   "come back to me by means of one click !!!" ;

                   this.ControlBox =true;

          }

          //to make control width depended on length of the text

          this.Width +=  this.Text.Trim().Length*4 ;

}

 

private void FormBasic_Activated(object sender, System.EventArgs e)

{

          //to catch command "To close forms"

          if (this.Name != "Form1" && closeForms )

          {

                   this.Close ();

          }

}

Open Buttons.cs code page and add command "Close forms ! " (that is "Go home ! ") to button_CHome_Click :

private void button_CHome_Click(object sender, System.EventArgs e)

{

          if (ClickHome !=null)

          {

                   ClickHome(this,e);

                   FormBasic.closeForms = true;//command : "Close Forms ! "

                   closeForm ();

          }          

}

That is all ! Now you may test the project.

Just run your project and open (click on the "Next" button) as many forms as you want. Click on "Home" button and ... All your forms will have been closed and you will have arrived "home".

CONCLUSION

In order to return to your "Home"  form in some Windows Forms project all that you need are only a few things . You have to

  • build solution in the way described above ( pay attention ! It can help in many cases), 
  • use inheritance for creating forms ( that is use a BaseForm),
  • use a user control for creating your "Home" button, 
  • initialize some public static bool variable to command "Go home" (or "Close forms" , it doesn"t matter)
  • and then using a few lines of code and Activated event to catch the command 
  • and close all forms except your "Home" form.

Good luck in programming !