Multi Document Interface (MDI) tab page browsing with C#

An article on tab page browsing in MDI Windows forms.

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Introduction

Multi Document Interface (MDI) tab page browsing has been very popular among many Windows applications especially internet browsers such as Opera, Mozilla, Maxthon and many others. After failing to find an article on it, I decided to write one myself to show any interested reader that creating an MDI tab page browsing can be done with pretty simple but neat coding. All that is needed is a little creativity.

Using the code
The source code is a template of the tab page window application. The template can be used for creating a tab-page capable window program.

The code
First, in the parent form, set the IsMDIContainer property to true. Attach a TabControl component to the form and set the Dock property to Top.

Next, in the child form, create a non-initialized TabControl and a TabPage. Create a property for these two objects. Later, we will see that these two objects will contain references to the TabControl in the parent form and the corresponding child TabPage.

private TabControl tabCtrl;
private TabPage tabPag;
public TabPage TabPag
{
get
{
return tabPag;
}
set
{
tabPag = value;
}
}
public TabControl TabCtrl
{
set
{
tabCtrl = value;
}
}


When the MDI child form is closing, destroy the corresponding tab page.
private void MDIChild_Closing(object sender, System.ComponentModel.CancelEventArgs e)
{
//Destroy the corresponding Tabpage when closing MDI child form
this.tabPag.Dispose();
//If no Tabpage left
if (!tabCtrl.HasChildren)
{
tabCtrl.Visible = false;
}
}
When the MDI child form is activated, activate the corresponding tab page.
private void MDIChild_Activated(object sender, System.EventArgs e)
{
//Activate the corresponding Tabpage
tabCtrl.SelectedTab = tabPag;
if (!tabCtrl.Visible)
{
tabCtrl.Visible = true;
}
}


When the child form is created, add the reference values of the TabControl and TabPage to its fields.
private void NewMenuItem_Click(object sender, System.EventArgs e)
{
//Creating MDI child form and initialize its fields
MDIChild childForm = new MDIChild();
childForm.Text = "MDIChild " + childCount.ToString();
childForm.MdiParent = this;
//child Form will now hold a reference value to the tab control
childForm.TabCtrl = tabControl1;
//Add a Tabpage and enables it
TabPage tp = new TabPage();
tp.Parent = tabControl1;
tp.Text = childForm.Text;
tp.Show();
//child Form will now hold a reference value to a tabpage
childForm.TabPag = tp;
//Activate the MDI child form
childForm.Show();
childCount++;
//Activate the newly created Tabpage
tabControl1.SelectedTab = tp;
}


When a tab page is selected, activate its corresponding MDI child form.
private void tabControl1_SelectedIndexChanged(object sender, System.EventArgs e)
{
foreach (MDIChild childForm in this.MdiChildren)
{
//Check for its corresponding MDI child form
if (childForm.TabPag.Equals(tabControl1.SelectedTab))
{
//Activate the MDI child form
childForm.Select();
}
}
}

That's all!