Develop Reference

Adding panels programatically based on .top is being based on the scroll of its parent

I am looking for some assistance in fixing an issue. At the moment I have developed some code that adds a user control to a panel. It adds multiple user controls to the panel and does this based on the .top feature. However, once the panel that I am adding the user controls to is scrolled down the user controls seem to be placed strangely.
I have already tried to adjust the .top value but I am not sure how to do it in relation to the scroll of the panel.
int i = 0;
foreach(memberInformation mi in pnlMembers.Controls.OfType<memberInformation>())
{
try
{
if (UserInformation.isPartyLeader)
{
mi.canUserEdit = "true";
}
else
{
mi.canUserEdit = "false";
}
mi.playerName = downloadInfo.Split(':')[i].Split(',')[0];
mi.playerRole = downloadInfo.Split(':')[i].Split(',')[1];
}
catch
{
pnlMembers.Controls.Remove(mi);
}
i++;
}
VIDEO to show what is happening: https://gyazo.com/985566afb7e4bab464dd06da191a0710
https://gyazo.com/4b0514cbdb310ea8abc46a397458130c

The correct way in order to position panels inside another panel is to use flowlayoutpanel.
Thanks

Auto Scroll Table Layout Panel does not start at top

I am working on a very simple table layout application for getting started with learning C#. I am doing everything programmatic ally ( not through design editor)
I am trying to add scrolling onto the application. It seems to work fine, but it does not seem to start at the top of the horizontal range by default. I tried adding things like Max/min size, autoscroll margins etc., but nothing seems to have the desired effect. I am sure there is something simple I am missing.
Here is my current code as it relates to the problem.
layout = new TableLayoutPanel();
layout.Height = 1075;
layout.Width = 704;
layout.Name = "masterLayout";
layout.Dock = DockStyle.Fill;
layout.AutoScroll = true;
int i = 0;
foreach (Race r in ELECTION_DATA.races.OrderBy(o => o.race_id)) {
layout.Controls.Add(new Label { AutoSize = true, Text =r.race_id, Name=r.race_id, Width=300}, i, 0 );
layout.Controls.Add(new TreeView { AutoSize = true, Text = r.race_id, Name = r.race_id, Height = 1000, Width = 300 }, i,1);
i += 1;
}
Controls.Add(layout);
Here is an image, The Label Control Is not visible because the scroll is offset to the beginning of the tree view.
How can I ensure the scroll always starts at the very top?

The ScrollLayoutPanel has a method called ScrollControlIntoView that will move a specific control inside the panel into view. If you just scroll your first control into the view after you are done filling your panels, then that should ensure that the top is visible. In other words:
// do your loop first...
foreach (...)
{
layout.Controls.Add(...);
}
// then if any controls exist, scroll the first control into view
if (layout.Controls.Count > 0)
{
layout.ScrollControlIntoView(layout.Controls[0]);
}

Winforms Control with custom LayoutEngine

In C# WinForms, if a control is docked then the margin is never used. In most cases the trick would be to place the control inside a panel with some padding. Now I'm looking for a solution without the container-panel, because my control is already a descendant of panel. So for the user it would be confusing an I would have route most of the properties from the container-panel to the inner panel.
My first try was a custom LayoutEngine but there is not much on that topic. But it kinda works. But I've some problems with the surrounding (sibling controls) they overlap the part which I made my control "bigger" (margin). In my custom layoutengine is make the control Size bigger (adding the margin) and moving the x/y accordingly
Image Custom Panel
The green control is my custom panel, which is docked bottom and has an margin of 10, the red control is a normal panel which is also docked bottom.
Now I could resize the sibling controls but I think this would make more problems? Is there any way to tell the other (sibling) controls that the size of my control has changed and that they should update their layout?
public class CustomLayoutEngine : LayoutEngine
{
public override bool Layout(object container, LayoutEventArgs layoutEventArgs)
{
bool result = base.Layout(container, layoutEventArgs);
Control parent = container as Control;
if (parent.Dock == DockStyle.Bottom && (parent.Margin.Left > 0 || parent.Margin.Right > 0))
{
Int32 newWidth = parent.Size.Width - (parent.Margin.Left + parent.Margin.Right);
Int32 newHeight = parent.Size.Height - (parent.Margin.Bottom);
parent.Size = new Size(newWidth, parent.Size.Height);
parent.Location = new Point(parent.Location.X + parent.Margin.Left, parent.Location.Y - parent.Margin.Bottom);
}
return result;
}
}

Allow a ListBox to overlap a TableLayoutPanel (C# .NET)

I have a form that contains a TableLayoutPanel with various controls and labels in it. One of them is a custom control that inherits from ComboBox that has extra auto-complete behavior (auto-completes on any text rather than just left to right). I didn't write the code for this control, so I'm not super familiar with how it works, but essentially upon clicking on the Combobox, it adds a ListBox below the ComboBox, within the same Panel of the TableLayoutPanel, that covers the normal drop down.
Unfortunately, the TableLayoutPanel prevents the ListBox from being fully visible when added, and only one item is shown. The goal is to get it to look like a normal ComboBox which would drop down to cover any controls below it.
Is there any way to allow a control that is in a TableLayoutPanel to overlap the TableLayoutPanel to get this to work as I want? I want to avoid any controls moving around due to the TableLayoutPanel growing to accommodate the ListBox.
Relevant code from the control:
void InitListControl()
{
if (listBoxChild == null)
{
// Find parent - or keep going up until you find the parent form
ComboParentForm = this.Parent;
if (ComboParentForm != null)
{
// Setup a messaage filter so we can listen to the keyboard
if (!MsgFilterActive)
{
Application.AddMessageFilter(this);
MsgFilterActive = true;
}
listBoxChild = listBoxChild = new ListBox();
listBoxChild.Visible = false;
listBoxChild.Click += listBox1_Click;
ComboParentForm.Controls.Add(listBoxChild);
ComboParentForm.Controls.SetChildIndex(listBoxChild, 0); // Put it at the front
}
}
}
void ComboListMatcher_TextChanged(object sender, EventArgs e)
{
if (IgnoreTextChange > 0)
{
IgnoreTextChange = 0;
return;
}
InitListControl();
if (listBoxChild == null)
return;
string SearchText = this.Text;
listBoxChild.Items.Clear();
// Don't show the list when nothing has been typed
if (!string.IsNullOrEmpty(SearchText))
{
foreach (string Item in this.Items)
{
if (Item != null && Item.ToLower().Contains(SearchText.ToLower()))
{
listBoxChild.Items.Add(Item);
listBoxChild.SelectedIndex = 0;
}
}
}
if (listBoxChild.Items.Count > 0)
{
Point PutItHere = new Point(this.Left, this.Bottom);
Control TheControlToMove = this;
PutItHere = this.Parent.PointToScreen(PutItHere);
TheControlToMove = listBoxChild;
PutItHere = ComboParentForm.PointToClient(PutItHere);
TheControlToMove.Anchor = ((System.Windows.Forms.AnchorStyles)
((System.Windows.Forms.AnchorStyles.Left | System.Windows.Forms.AnchorStyles.Right)));
TheControlToMove.BringToFront();
TheControlToMove.Show();
TheControlToMove.Left = PutItHere.X;
TheControlToMove.Top = PutItHere.Y;
TheControlToMove.Width = this.Width;
int TotalItemHeight = listBoxChild.ItemHeight * (listBoxChild.Items.Count + 1);
TheControlToMove.Height = Math.Min(ComboParentForm.ClientSize.Height - TheControlToMove.Top, TotalItemHeight);
}
else
HideTheList();
}
Images:
Desired behavior
Current behavior

Going on the suggestion from TaW, I came up with a tentative solution. This form isn't re-sizable but does auto-size so that it looks ok if the user changes their DPI in Windows.
To resolve this, I moved the control out of the TableLayoutPanel to an arbitrary position in the Parent of the TableLayoutPanel. On form loading, I summed the coordinates of the TableLayoutPanel and an empty panel in the cell that I wanted the control to be located on top of. This worked for my needs but it feels like a kludge.
The better solution is probably to use Control.PointToScreen and Control.PointToClient methods, however I wasn't able to get these methods to give me the correct coordinates.

How to use ctrl key + mouse click to select multiple controls?

Probably this question has already an answer here but I was not able to find it..
I have a tabControl with a flowlayoutpanel in each tab page where I can add controls at run time. I can rearrange them, move them across tab pages.. How can I select multiple controls to be able to move them around using ctrl key + mouse click?
This is my drag event so far:
private void control_DragDrop(object sender, DragEventArgs e)
{
Control target = new Control();
target.Parent = sender as Control;
if (target != null)
{
int targetIndex = FindCSTIndex(target.Parent);
if (targetIndex != -1)
{
string cst_ctrl = typeof(CustomControl).FullName;
if (e.Data.GetDataPresent(cst_ctrl))
{
Button source = new Button();
source.Parent = e.Data.GetData(cst_ctrl) as CustomControl;
if (targetIndex != -1)
fl_panel = (FlowLayoutPanel)tabControl1.SelectedTab.Controls[0];
if (source.Parent.Parent.Name == target.Parent.Parent.Parent.Name)
{
this.fl_panel.Controls.SetChildIndex(source.Parent, targetIndex);
}
else
{
target.Parent.Parent.Parent.Controls.Add(source.Parent);
this.fl_panel.Controls.SetChildIndex(source.Parent, targetIndex);
}
}
}
}
}
private int FindCSTIndex(Control cst_ctr)
{
fl_panel = (FlowLayoutPanel)tabControl1.SelectedTab.Controls[0];
for (int i = 0; i < this.fl_panel.Controls.Count; i++)
{
CustomControl target = this.fl_panel.Controls[i] as CustomControl;
if (cst_ctr.Parent == target)
return i;
}
return -1;
}

This is not an easy, nor a common task. But surely doable and depending on preconditions could become trivial without need to spend multi-man-year effort on it ^^.
You have many options:
controls support selection;
container control support children controls selection;
overlay.
Handling selection is pretty easy: have a dictionary (or a control property, possibly using Tag) to store if control is selected or not, show selection somehow, when control is Ctrl-clicked invert selection. You can even provide Shift-key selection.
As #Hans Passant commented, you can use overlay window (invisible window on top of everything) to draw selection reticle there as well as handle selection and dragging itself. Or it could be a custom control with property IsSelected, setting which will draw something (border?) to indicate selection.
Easiest option would be to create SelectionPanel control, which can host any other controls inside, has IsSelected indication and is draggable. When children is added subscribe to MouseUp/MouseDown events or you can only allow to drag if special area of SelectionPanel is clicked. To example, you could have option Enable dragging in your software, when set all SelectionPanels will display special area (header?) which you can drag or Ctrl-click.