Develop Reference

Is it possible to add a form to a TreeView?

I want to create a TreeView that contains complex forms of EmployeeNode as nodes. When you add the node I will call InitializeComponent(). So that the expected result will be something like
Or codewise:
EmployeeNode EMPND = new EmployeeNode(new Employee());
EMPND.Draw();
VisualTree.Nodes.Add(EMPND);
//Draw (at EmployeeNode form class)
public void Draw()
{
InitializeComponent();
}
Is this possible?
edit
If this cant be done using TreeView, I am open to hear about other ways to store forms, other then TreeView, that offers similar hierarchy - based WinForm visual solutions (maybe a generic version?)

Set the TopLevel property of the form you want to add as false.
var form = new Form { TopLevel = false };
treeView.Controls.Add(form);
form.Show();

Show top most Child Form c#

How can I show topmost a button clicked child form in my parent form (with a tabcontrol which docked as fill)?
It always shows the form at the back of the tabcontrol of the parent form, I've even used:
frm.TopMost = true;
frm.BringToFront();
Still shows at the back.

What you want is not possible. MDI children of a control get shown on a control (which you can't directly select) called MdiClient, which is not transparent (and can't be) and by default, goes always to the back of other controls in the parent form.
So the only way to do this, would be getting the MdiClient over the controls in the parent form: this would do what you expect, but it would also hide the parent controls when there are no child forms displayed (since again, the MdiClient is not, and can't be transparent).
So the only reasonable way would be having a maximized child form with the TabControl, instead of having that TabControl directly on the parent.
Or you could have your TabControl only shown when there are no child windows. For that, make a timer in the parent form, and check this at every interval:
if(MdiChildren.Length > 0)
myTabControl.SendToBack();
else
myTabControl.SendToFront();
This will only work if the MDI children are always maximized: your TabControl will not be visible when there are any children (no matter if they cover it or not)
Update
As remarked in the comments, you can have "your own MDI", by having a host control (a Panel, for example) in the parent form and loading the child forms in that control:
var form = new ChildForm();
form.TopLevel = false;
form.Parent = myHostPanel;
form.Show();
This would show the form inside the panel (which you can locate and zorder where you want)... you lose all the MDI management though, and you'll have to keep track of your children (and take care of the forms' events if needed) yourself.
I'd not use this solution, it's pretty hacky and can get messy for big applications (unless you do a correct system)
As a summary
Since we're discussing these methods in the comments
You can hack your way to do what you want, but you'll come into all sorts of problems with any approach.
If I was you, I'd redesign my application so that what you want to achieve is not needed. If you can't do that, the only sane way would be just not having those controls in the parent form, have an always-maximized, non-closable MDI child form with those controls, and skip that window everytime you need to work in the MDI children collection.

Please explain what components of what frameworks you are using and what you have done so far. Without that information i suggest the following solution (untested).
In the "ButtonClick" event of your ParentForm do this:
ChildForm cf = new ChildForm();
cf.MdiParent = this;
cf.Show();
If this doesn't work you may add a
cf.Focus();

This question make me uncomfortable :). after a lot of testing, I can't really find a solution. neither BringToFront() Function nor SendToBack() Work Properly. maybe the following approach can help you. I use IntersectWith Function of Rectangle Class and test if form intersect with tabControl or not. if so change the tab control visibility to false otherwise true. take a look at the following code:
first make form declaration public at the mdi parent form:
public partial class MdiParentForm : Form
{
Form frm = new Form();
}
After that when you initialize your child form, add some handler to its locationChanged event, like this:
frm.MdiParent = this;
frm.LocationChanged += Frm_LocationChanged;
frm.Show();
And at the end, This is the handler:
private void Frm_LocationChanged(object sender, EventArgs e)
{
Rectangle tabControlRectangle = new Rectangle(tabControl1.Location, tabControl1.Size);
Rectangle childFormRectangle = new Rectangle(frm.Location, frm.Size);
if (tabControlRectangle.IntersectsWith(childFormRectangle))
{
tabControl1.Visible = false;
}
else
{
tabControl1.Visible = true;
}
}
Thanks to #Jcl, Problem with this is that the tab control will hide and show as long as any point of the child form touches its rectangle. Moving the child form around would be horrible :-)

Set form as Parent throw exception "Top-level control cannot be added to a control"

I want to access variables of a form from another form. On clicking a button inside my Main form, I want to set my Main form as Parent, then bring up another form (child form) wherein I will access variables of the Main form. My click handler is as follow:
private void btnSystem_Click(object sender, EventArgs e)
{
Form_EnterPassword EP = new Form_EnterPassword();
EP.Parent = this; //error: Top-level control cannot be added to a control
EP.ShowDialog();
}
It compiles fine without any error. However, when I run the Main form and click on the System button, it throws me an exception. I do something similar in another code (not mine) with the same button click, and encounter no error (just with setting Main form as Parent).
What am I doing wrong? Is there something in my Main code that cause this?

Best way would be to use EP.ShowDialog(this) and later use Owner property.

You need the EP.TopLevel property to be set to false. It will let you to set a parent to it.
Further reading.
In case you only want to access variables and controls of another form, then maybe you can reach it in other ways, not trough a Parent relationship.

OK,
apparently the way to do it is to call
Form_Child.ShowDialog(this)
and then I can call
FromParent_aVariable = ((Form_Parent)this.Owner).aVariable;
or if I define aVariable in the namespace Properties then
FromParent_aVariable = NameSpace.Properties.Settings.Default.aVariable;
there are two ways.

Form_EnterPassword EP = new Form_EnterPassword();
EP.MdiParent = this;
EP.Show();
try this way, it helps for me. you need to set principalform as isMdicontainer = true at the form properties

I had a similar situation recently.
I was attempting something similar but by controlling the Child Forms from a different class.
Note(s):
You're trying to set the Child Form(s) "TopMost" to something that does not allow it.
In this case the "MdiContainer".
To accomplish this:
• Disable MainForm "isMdiContainer" property (its use is kind of obsolete anyway).
• Set the Form(s) TopMost properties to true.
• You should now be able to accomplish your feature.
**Code Example:**
/* On your Main Form Class */
private void btnSystem_Click(object sender, EventArgs e)
{
// Instantiate the Form_EnterPassword by passing the MainForm
Form_EnterPassword EP = new Form_EnterPassword(this);
EP.Show(); // No longer as modal Form to display in front.
}
/* Under your EnterPassword Form Class */
// Do not create a new Instance of MyMainForm.
// You want to use the same thread as your MainForm
private MyMainForm mainForm;
/* Constructor */
public Form_EnterPassword(MyMainForm form)
{
mainForm = form;
this.Owner = mainForm; // "this" refers to the: EnterPassword Form.
}
Remarks:
The only additional thing that you (may) have to do, (to achieve perfection) is to check the MainForm > WindowState; and create a code block to minimize or bring the Forms to their specific state.
i.e:
if (WindowState == FormWindowState.Minimized)
{ /* Code to Minimize all the Child Forms. */ }
else { /* Code to bring all Forms to their "Normal" State */ }

Writing this way, made the dialog display on the center of the parent form.
Form_Child.StartPosition = FormStartPosition.CenterParent;
Form_Child.ShowDialog(this);

C# call MDI child from child form

I have these forms:
MainScreen - MDI container
DataBaseOutput - child
NewAnime - child
DataBaseOutput has a tab control that holds datagrids, each for different tables. I use an access database.
In those tabs, there is a menustrip, where the functions "New", "Edit", "Delete" etc. will be called from. Now when I'm on the first tab's menustrip and click on "New" I want to open the form "NewAnime", inside the MDI container. This however, is not working as I planned. At first I tried to just call it from the childform (DataBaseOutput). This resulted in opening a new form instead of a child. when I made it a child it was not showing up.
Then I triend lots of things, but I still haven't figured it out.
This is the current code for calling the form. It calls the form with a method in the main form:
private void NewAnime_Click(object sender, EventArgs e)
{
MainScreen main = new MainScreen();
main.mShowForm(2);
this.Close();
}
Method in the main form:
// Forms for MDI Parent
DataBaseOutput OutputForm = new DataBaseOutput();
NewAnime AddAnime = new NewAnime();
// How i made them childs (this is at the InitializeComponent(); part)
OutputForm.MdiParent = this;
AddAnime.MdiParent = this;
public void mShowForm(int formnumber)
{
switch (formnumber)
{
case 1: OutputForm.Show(); break;
case 2: AddAnime.Show(); break;
}
}
Does anyone have a clue of what i'm doing wrong and maybe has a better idea? This might be a bit too much working around, but as I said, it's my first time using MDI forms and i'm just trying to get it to work.

Have you set the MainForm to be an MDIContainer? To do this set its IsMdiContainer property to true; Also check it has File and Window top-level menu items and New and Close menu items. (The tutorial suggests this, I know it should have a Window menu item at least).
Have a look at this tutorial for more guidance: Creating MDI Child Forms (MSDN)
EDIT: Looking at it more closely, it seems you are creating a new instance of MainForm, and trying to show the form as a child of that instance, as opposed to showing it in the existing MainForm. I assume you already have an instance of MainForm open at this point? And assuming the OutputForm and AddAnime forms are children of MainForm you could call the existing instance's method like this:
private void NewAnime_Click(object sender, EventArgs e)
{
this.ParentForm.mShowForm(2);
this.Close();
}
but ideally you should have an event on DataBaseOutput that MainForm listens to, and shows the new Form when the event is raised. See here for more info (it talks about user controls and not child forms, but the principle is the same):
Calling parent form functions from a user control

.NET MDI child form suppress/hide caption/icon area

I have a subform (child) that I want to use in a number of parents. I'm not a professional developer (I'm an architect - I know, you can save all the jokes... :) - working solo at present). I've ended up using an MDI form with the subform as a child. I maximize the subform form and most things are fine except that although I've tried to disable all the various widgets (the subform in the designer shows NO caption/icon/button area), I get TWO icons on the left and TWO sets of buttons on the right - of which ONLY the restore button works. Either of the sets of buttons will work the one child form.
Is there any way around this? I want the subform to be "transparent" the the user - they shouldn't be aware there's a subform in use.
I've done a quick search and I'd already suppressed the actual caption as mentioned in another answer - to get the caption bar suppressed in the designer...
Is MDI the right technology, or is there a better way to have the same subform appear in multiple parent forms?
VS2008, C#, Windows 7
TIA,
Paolo

There's a WF bug that will double the glyphs if you create the MDI child form in the parent's constructor. Here's an example:
public partial class Form1 : Form {
public Form1() {
InitializeComponent();
this.IsMdiContainer = true;
var child = new Form();
child.MdiParent = this;
child.WindowState = FormWindowState.Maximized;
child.Show();
}
}
Move the child form creation code to the Load event to avoid this.