Im creating custom scrollbar control that can bind to containers like panel, flowlayouts etc.
Here is the problem, when the custom scrollbar is bound to let me say a panel it disables autoscroll and when autoscroll is off the panel doesnt give accurate VerticalScroll and HorizontalScroll values when the custom scrollbar is bound to the panel for the first time unless i say autoscroll = true; autoscroll = false; after that everything works well. but this creates the panel to show and hide its default scrollbars causing flickers.
//_control = panel, this = custom scrollbar
_control.AutoScroll = true; // these two lines fix the problem but causes flickers.
_control.AutoScroll = false;
if (_vertical)
{
this.Maximum = _control.VerticalScroll.Maximum + 1 - _control.VerticalScroll.LargeChange;
this.Minimum = _control.VerticalScroll.Minimum;
this.Value = _control.VerticalScroll.Value;
}
else
{
this.Maximum = _control.HorizontalScroll.Maximum + 1 - _control.HorizontalScroll.LargeChange; ;
this.Minimum = _control.HorizontalScroll.Minimum;
this.Value = _control.HorizontalScroll.Value;
}
_control.Scroll -= _control_Scroll;
_control.Scroll += _control_Scroll;
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
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]);
}
I have a panel1 with AutoScroll = true.I have to make panel1 scroll with btnUp and btnDown. So far I've made what I was asked for
private void btnUpClicked(Object sender, EventArgs e)
{
if (panel1.VerticalScroll.Value - 55 > 0)
panel1.VerticalScroll.Value -= 55;
else panel1.VerticalScroll.Value = 0;
}
private void btnDownClicked(Object sender, EventArgs e)
{
panel1.VerticalScroll.Value += 55;
}
But now I need to hide Scrollbar or make it invisible. I tried
panel1.VerticalScroll.Visible = false;
but it doesn't work. Any ideas guys?
Ok, I've done the working example of this for you. All you have to do is to change the max value depending on the total size of all the items inside your panel.
Form code:
public partial class Form1 : Form
{
private int location = 0;
public Form1()
{
InitializeComponent();
// Set position on top of your panel
pnlPanel.AutoScrollPosition = new Point(0, 0);
// Set maximum position of your panel beyond the point your panel items reach.
// You'll have to change this size depending on the total size of items for your case.
pnlPanel.VerticalScroll.Maximum = 280;
}
private void btnUp_Click(object sender, EventArgs e)
{
if (location - 20 > 0)
{
location -= 20;
pnlPanel.VerticalScroll.Value = location;
}
else
{
// If scroll position is below 0 set the position to 0 (MIN)
location = 0;
pnlPanel.AutoScrollPosition = new Point(0, location);
}
}
private void btnDown_Click(object sender, EventArgs e)
{
if (location + 20 < pnlPanel.VerticalScroll.Maximum)
{
location += 20;
pnlPanel.VerticalScroll.Value = location;
}
else
{
// If scroll position is above 280 set the position to 280 (MAX)
location = pnlPanel.VerticalScroll.Maximum;
pnlPanel.AutoScrollPosition = new Point(0, location);
}
}
}
Picture example:
You have to set AutoScroll option to False on your panel. I hope you understand what I've done and will get your panel running the way you want. Feel free to ask if you have any questions.
The Panel control takes on the duty you gave it by setting AutoScroll to true pretty serious. This always includes displaying the scrollbar gadget if it is necessary. So what you tried cannot work, hiding the vertical scrollbar forces Panel to recalculate layout since doing so altered the client area. It will of course discover that the scrollbar is required and promptly make it visible again.
The code that does this, Panel inherits it from ScrollableControl, is internal and cannot be overridden. This was intentional.
So using AutoScroll isn't going to get you anywhere. As an alternative, do keep in mind what you really want to accomplish. You simply want to move controls up and down. Easy to do, just change their Location property. That in turn is easiest to do if you put the controls on another panel, big enough to contain them. Set its AutoSize property to True. And implement you buttons' Click event handlers by simply changing that panel's Location property:
private const int ScrollIncrement = 10;
private void ScrollUpButton_Click(object sender, EventArgs e) {
int limit = 0;
panel2.Location = new Point(0,
Math.Min(limit, panel2.Location.Y + ScrollIncrement));
}
private void ScrollDownButton_Click(object sender, EventArgs e) {
int limit = panel1.ClientSize.Height - panel2.Height;
panel2.Location = new Point(0,
Math.Max(limit, panel2.Location.Y - ScrollIncrement));
}
Where panel1 is the outer panel and panel2 is the inner one that contains the controls. Be careful when you use the designer to put controls on it, it has a knack for giving them the wrong Parent. Be sure to use the View + Other Windows + Document Layout helper window so you can see this going wrong. After you filled it, set its AutoSizeMode property to GrowAndShrink so it snaps to its minimum size.
Try this:
panel.AutoScroll = true;
panel.VerticalScroll.Enabled = false;
panel.VerticalScroll.Visible = false;
Edit:
Actually when AutoScroll = true; It will take care of hscroll and vscroll automatically and you wont be able to change it. I found this on Panel.AutoScroll Property on MSDN
AutoScroll maintains the visibility of the scrollbars automatically. Therefore, setting the HScroll or VScroll property to true has no effect when AutoScroll is enabled.
You may try this to workaround this problem, I have copied it from this Link.
Behavior Observations 1:
If AutoScroll is set to true, you can't modify anything in VerticalScroll or HorizontalScroll. AutoScroll means AutoScroll; the control decides when scrollbars are visible, what the min/max is, etc. and you can't change a thing.
So if you want to customize the scrolling (e.g. hide scrollbars), you must set AutoScroll to false.
Looking at the source code for the ScrollableControl with Lutz Roeder's .NET Reflecter, you can see that if AutoScroll is set to true, it ignores your attempts to change property values within the VerticalScroll or HorizontalScroll properties such as MinValue, MaxValue, Visible etc.
Behavior Observations 2:
With AutoScroll set to false, you can change VerticalScroll.Minimum, VerticalScroll.Maximum, VerticalScroll.Visible values.
However, you cannot change VerticalScroll.Value!!! Wtf! If you set it to a non-zero value, it resets itself to zero.
Instead, you must set AutoScrollPosition = new Point( 0, desired_vertical_scroll_value );
And finally, SURPRISE, when you assign positive values, it flips them to negative values, so if you check AutoScrollPosition.X, it will be negative! Assign it positive, it comes back negative.
So yeah, if you want custom scrolling, set AutoScroll to false. Then set the VerticalScroll and HorizontalScroll properties (except Value). Then to change the scroll value, you need to set AutoScrollPosition, even though you aren't using auto scrolling! Finally, when you set the AutoScrollPosition, it will take on the opposite (i.e. negative) value that you assign to it, so if you want to retrieve the current AutoScrollPosition later, for example if you want to offset the scroll value by dragging the mouse to pan, then you need to remember to negate the value returned by AutoScrollPosition before reassigning it to AutoScrollPosition with some offset. WOW. Wtf.
One other thing, if you are trying to pan with the mouse, use the values of Cursor.Position rather than any mouse locations returned by the mouse events parameters. Scrolling the control will cause the event parameter values to be offset as well, which will cause it to start firing mouse move events complete with undesired values. Just use Cursor.Position, because it will use mouse screen coordinates as a fixed frame of reference, which is what you want when you're trying to pan/offset the scroll value.
I have a form with a scrollable panel and two controls sitting right on top of each other - one visible one not. Based on a certain condition when that form is activated I might swap the visible properties of the two controls. These controls are at the bottom of the scrollable panel. If when I leave that form I leave it scrolled to the bottom, go change the condition that will cause the controls' visibility to swap and go back to that form the visible control will have dropped about 200px down the page leaving a large gap. Anyone know what could be causing this? I tried resetting the scrollbar position to the top on form close but that just causes a smaller gap and sometimes the control to move higher into other controls. Any ideas?
Here is an example that reproduces the problem. If the mouse is moved over the red label, the visibility of button2 is changed to true which causes the scroll jumps back up to Button1.
public class Form123456 : Form {
public Form123456() {
Controls.Add(new UC1());
}
public class UC1 : UserControl {
Button b1 = new Button { Text = "Button1" };
Label lb = new Label { Text = "_", AutoSize = true, BackColor = Color.Red };
Button b2 = new Button { Text = "Button2", Visible = false };
Button b2b = new Button { Text = "x" };
Button b3 = new Button { Text = "Button3" };
public UC1() {
AutoScroll = true;
Dock = DockStyle.Fill;
b1.Location = new Point(0, 200);
b2.Location = new Point(0, 600);
lb.Location = new Point(70, 600);
b2b.Location = new Point(90, 600);
b3.Location = new Point(0, 800);
Controls.Add(b1);
Controls.Add(b2);
Controls.Add(lb);
Controls.Add(b2b);
Controls.Add(b3);
lb.MouseEnter += delegate {
b2.Visible = true;
};
lb.MouseLeave += delegate {
b2.Visible = false;
};
}
}
}
To fix it, one solution is to add this code:
protected override Point ScrollToControl(Control activeControl) {
return this.AutoScrollPosition;
}
Solution from:
Why does clicking in a text box cause an AutoScroll panel to scroll back to the top?
No repro. Sounds to me that you are doing more than just changing the Visible property. Whenever you assign the Location property, you have to add the AutoScrollPosition to compensate for the scroll state. Post code if this doesn't help.
Have you verified the order that you change visibility of the two controls?
The scroll bars on a container with auto scroll set to true will appear and disappear depending on the position of controls that are outside of the visible area of the control. Controls that are invisible do not count.
So in your case if you make both controls invisible at anytime, the scroll bars will disappear. They will come back when one control is made visible. So to make sure you don't have a jump in scroll bar position and controls position you should make sure that at no time are both controls invisible. Another solution is to have a pseudo-visible control on the container. That is a control that has its visibility set to true but it is not actually visible for the user (for example a dot of the color of the background, a label with no text ...). Position this control in the furthest position x,y and the scroll bars will never disappear..