"Z-Index" in WinForms - vb.net

In CSS, we have a Property called z-index, what is the same in WinForms set for a Panel control to the "Z-Index?

WinForms has a z-order, but you can't access it as a number. Instead, every control has a BringToFront method and a SendToBack method, which move the control to the top of the z-order or to the bottom, respectively.
Not sure exactly why it was exposed this way, although you rarely encounter situations where either BringToFront or SendToBack don't provide what you need.
Update: I'm wrong, you can access the z-order directly via a method on the control's container's Controls collection. Here's a simple method that wraps it:
public void SetControlZOrder(Control ctrl, int z)
{
ctrl.Parent.Controls.SetChildIndex(ctrl, z);
}
I'm guessing they encapsulated this in BringToFront and SendToBack just to keep everything simple and easy to use. I applaud.
Update 2: I interpreted your comments to a different answer here to mean that you want to be able to take a control that is inside a panel and larger than the panel (so that part of it is hidden) and make it so that the control is in front of the panel and larger than it (so that you see the whole control).
You can do this by removing the control from the panel, shifting its position by the original panel's position, and adding it to the form's controls:
panel1.Controls.Remove(button1);
button1.Left += panel1.Left;
button1.Top += panel1.Top;
this.Controls.Add(button1);
The Left and Top shifts are necessary because the button's position was originally relative to the panel, and will now be relative to the form. The shifts keep it in the original virtual position, so it appears to come out of the panel.
You would then have to deal with putting it back in the panel, which is just a reverse of the above code.

Related

What technique will I use if i want to change this panel when I click a button in VB

I just have it in my mind. And I can't explain it so here it goes.
A system that only uses 1 form?
It have a two panel, left and right.
The left is consist of buttons
Then the right is associated on the buttons and will change whether what button will be clicked.
Any ideas?
My preference is to do this via custom controls, rather than panels... but panels can work too.
There are a number of ways to do this:
Keep all of the controls layered on top of each other, and then set the Visible property to false for controls/panels you don't care about and to true for the Control/Panel that you do
Move the controls you don't care about out of the visible area
Remove/Add the Controls/Panels from Form's controls collection entirely
I think you can also get a TabControl to put the tabs along the left side, with some formatting that looks more like buttons, such that what you want will be handled without needing to write any code to switch layouts
Any of those can work. Whichever option you use, I have two recommendation for controlling layout and making the transitions smooth.
Call SuspendLayout() before making any changes, and then call ResumeLayout() when you're done. This will help avoid stuttering or a partially rendered form.
Look at the TableLayoutPanel Control. This control will allow you to arrange your top-level panels so that they can be resized with proportion. If you also then dock your individual panels, you can quickly build your program so that it resizes correctly.
You can have several panels, one on top of another. Change their visibility, depending on which one you need at a given moment.
Option #2 would be using a vertical tab control (or a tab strip - see another answer there).

Increasing the space inside a windows form

I am trying to populate my windows form with new controls and data based on what is read from my database. The left side of the form is a static panel which will not need re sizing but I need to create multiple labels on the right side which requires more space. I added the vscroll control but am having trouble increasing the size of the right side of the form.
To use a scroll-bar will require a semi-low-level implementation where you need to always update the view by repositioning the elements, calculating your scroll-bar in relation to total view, what elements would be visible and so forth.
A better solution in this case will probably be to add a Panel control on the right which is docked (f.ex. Fill) and then set the AutoScroll property to True.
This way you leave all the "low level" stuff to the Panel control and you can add and position the elements you need to the Panel's Controls collection instead.

FlowLayoutPanel not showing all contents?

Very weird situation going on with a FlowLayoutPanel...
I have been dynamically adding user controls to my panel. This user control has a height of 105. If I have my FlowLayoutPanelwidth to only show 1 "column" of controls, it will only display 296 of them. The rest of the controls are grayed out at the bottom of the flowlayoutpanel. If I widen the flp to allow 2 "columns" of controls, I can see 592 of them, with the remainder grayed out at the bottom. I have gone in and resized the user control to make it shorter in height, which works in some respects (i.e. it works when I have two columns, but not just 1), and can go forward with this work-around.
So, I guess my question is, why does the FlowLayoutPanel behave in this fashion? It seems (based on what I saw) that there is a limit to how much data the FLP will show at one time.
Your comment just reminded me that when you're adding many controls to any container it is a good idea to do this:
YourPanel.SuspendLayout();
// populate panel with controls
YourPanel.ResumeLayout(false);
This in effect stops the container (panel) from re-rendering itself every time you add a control until you're done adding controls. In the very least your panel creation will be smoother and faster. Not sure if this might fix your issue or avoid the need for a hack with PerformLayout.
If you look at your Form's designer file you will actually see this in action in the InitializeComponent function.

winforms - usercontrol with dockstyle fill not correct size during form load

My main form has two panels, left docked and right docked. The right side panel has two child panels with top dock and bottom dock settings. The usercontrol is added to the right side top panel.
My usercontrol has a panel and a label. The panel is anchored on all 4 sides, the label is anchored on all except the bottom. At runtime I create this usercontrol and set it to dockstyle=fill and then I add it to my top right panel.
With everything set to "fill" I expect that when I add my usercontrol to the panel it will take on the appropriate width and height and pass that info to the child controls (labels) inside of my usercontrol.
My problem is that this stretching of the size does not happen when I create my objects during the Load event on my usercontrol. Even though initializecomponent has ran for the usercontrol the panel inside of it (4 corners anchored) has not taken the x/y values of the available space. As a result my usercontrol shows up about 50% of the width I want.
Lets say that instead of creating objects during usercontrol load that I instead start a timer and have the timer call my create routine when it raises the tick event. When I do things like this my objects are created with the full width/height that I expect. The only issue here is that this causes a delay in my interface.
Can someone help explain this behavior? My mainform is calling a "load gui" routine which is instantiating usercontrols, setting panel sizes, and then adding usercontrols to those panels. This particular user control is the last to load into the panels from that load gui routine so it does not make sense that the parent panel width/height would not be known yet. This is one of my first apps where I am purposely trying to use dockstyle=fill to keep things consistent across different main form sizes without writing all the extra size_changed code handlers. I'm sure this one is easy to work around once I know where the problem lies.
Thanks for any help provided!
this turned out to be a padding issue on the parent usercontrol. I also had to allow a bit of wiggle room to make sure that the controls didn't overflow the panel so I did a parent.width - 15 and that along with the padding made everything work much better.

How can I show scrollbars on a PictureBox control?

Sometimes, I have a picturebox lets say 100x100. But the image it will display is actually 100x400.
I don't want to increase the size of the picturebox itself. Instead, I would like to create a vertical scrollbar (or horizontal if needed).
I could not find a scrollbar in the toolbox, so I guess I have to code it. But, how?
And I still wonder if I didn't make a mistake and didn't see the scrollbar in the toolbox. My apologies then :(
I suppose you could add separate scrollbar controls and sync their Scroll events up with the offset at which the picture in the PictureBox is drawn, but that sounds like actual work. There's a better way.
Add a Panel control to your form, and set its AutoScroll property to "True". This will cause the control to automatically show scrollbars when it contains content that lies outside of its currently visible bounds. The .NET Framework will take care of everything for you under the covers, without you having to write a single line of code.
Drag and drop your PictureBox control inside of the Panel control that you just added. The Panel control will then detect that one of its child controls is larger than its visible area and show scrollbars, thanks to the AutoScroll property. When the user moves the scrollbars, the portion of the image in your PictureBox that is visible will be automatically adjusted. Magic.
(The reason you have to use a Panel control as a container is because PictureBox does not inherit directly from the ScrollableControl base class, which is what provides the AutoScroll property.)
I tried this and it worked well. But I noted that if the picturebox is docked in the panel, the picturebox is automatically set to the size of the parent panel, and can't be set larger (at least not in any way I could find). This defeats the purpose of the technique. So -- put the picturebox on the panel, but don't dock it, and it will work perfectly.
There are no automatic scroll bars on a picture box, but you can add the VScrollBar (and HScrollBar) control to the form and handle the image scrolling manually by redrawing it at a different offset each time the Scroll event is fired.