I have a control whose parent is a ScrollableControl. How do I find the part of the control that's actually visible to the user? Both are rectangular - there's no funny business with Regions.
I think the GetVisibleRectangle method I wrote below is what you were requesting. Successive runs of this with scrolling yielded the following output as the control was scrolled:
{X=0,Y=0,Width=0,Height=0} - button4 was scrolled out of view. Note that the value here is Rectangle.Empty.
{X=211,Y=36,Width=25,Height=13} - button4 was scrolled so the upper left corner was visible
{X=161,Y=36,Width=75,Height=13} - button4 was scrolled so the top half and entire width was visible
{X=161,Y=26,Width=75,Height=23} - button4 was scrolled to be entirely visible
Note how in addition to the Width and Height changes that the X,Y also changed with scrolling.
Source:
private void button1_Click(object sender, EventArgs e)
{
Rectangle r = GetVisibleRectangle(this.panel1, button4);
System.Diagnostics.Trace.WriteLine(r.ToString());
}
public static Rectangle GetVisibleRectangle(ScrollableControl sc, Control child)
{
Rectangle work = child.Bounds;
work.Intersect(sc.ClientRectangle);
return work;
}
AutoScrollPosition represents the location of the scrollable control's display rectangle. The X and Y coordinate values retrieved are negative if the control has scrolled away from its starting position (0,0). When you set this property, you must always assign positive X and Y values to set the scroll position relative to the starting position. For example, if you have a horizontal scroll bar and you set x and y to 200, you move the scroll 200 pixels to the right; if you then set x and y to 100, the scroll appears to jump the left by 100 pixels, because you are setting it 100 pixels away from the starting position. In the first case, AutoScrollPosition returns {-200, 0}; in the second case, it returns {-100,0}.
Source: MSDN: ScrollableControl.AutoScrollPosition Property
The following link might helps to resolve this problem
http://www.trace-solution.com/2012/06/how-to-get-visibleviewable-area-of-user.html .
Related
I have some string labels that are associated with a number each.
I've created a Chart element with one ChartArea and one Series which is using the SeriesChartType.Bar type to show my labels on the x-axis (which, confusingly, is the vertical axis when using the Bar type, but anyway...) and show the number as a bar next to it.
Since I have many labels that don't fit on the screen at once, I "enabled" the scrollbar using the Zoom method in my Paint event handler like this:
private void chart1_Paint(object sender, PaintEventArgs e)
{
var scaleView = chart1.ChartAreas.First().AxisX.ScaleView;
var pos = double.IsNaN(scaleView.Position) ? 0.0 : scaleView.Position;
scaleView.Zoom(pos, pos + chart1.Height / 22.0);
}
I don't know if this is the proper way to do that, but it does (almost) what I want:
show the scrollbar if there are too many data points (labels) to fit on the screen
update the visible area properly when the window is resized
There is only one annoying thing: If due to scrolling a long label appears in the visible area or disappears, the area occupied by the labels is adjusted to the longest visible label. I hope these screenshots explain what I mean:
Here one long label is visible (at the bottom):
Here I scrolled up by one unit so that the long label is not visible any more:
This is super annoying during scrolling as everything gets rescaled whenver a long label appears or disappears.
How to fix the area occupied by the labels to always fit the longest label in the series, no matter if it is currently visible or not? I tried IsLabelAutoFit = false for both, x- and y-axis, but that doesn't help.
Ok, I've got it. I used
chartArea.InnerPlotPosition.Auto = false;
InnerPlotPosition.X = 33.333;
to give one third of the chart area to the labels and the other two thirds to the bars.
InnerPlotPosition.Auto = false makes this fixed so that it doesn't update while scrolling.
Description Created a form in Winform C# app.
Added a panel (PBack) with dock type fill. (Scrollable)
Then added a picturebox(pbDraw) in panel(PBack) that height depends upon image size.
I want to add a control on the bottom left of the current screen view. (assume client scrolled down)
What i tried
Rectangle rect = Screen.GetWorkingArea(pbDraw);
ctrl.Top = rect.Top + rect.Height;
ctrl.Top = Screen.PrimaryScreen.WorkingArea.Top + Screen.PrimaryScreen.WorkingArea.Height;
ctrl.Top = Screen.FromControl(pbDraw).WorkingArea.Top+ Screen.FromControl(pbDraw).WorkingArea.Height;
Issue control is adding at top of pbDraw (0,0) and not on current screen bounds top.
As far as I understand, Control.Top takes the scrolled view into account all by itself.
Gets or sets the distance, in pixels, between the top edge of the control and the top edge of its container's client area.
So, you should be able to assign the coordinates relevant to the pBack and its client view:
ctrl.Top = pBack.Height - ctrl.Height;
Assuming that ctrl is a child of pBack this code should place it at the bottom of the current (scrolled) part of pBack
UPDATE:
As you said in the comments, ctrl is actually a child of pbDraw. In this case, you'll need to take the scrolling into account. For that, you can use Panel.VerticalScroll:
//scroll position + panel height - control height
ctrl.Top = pBack.VerticalScroll.Value + pBack.Height - ctrl.Height;
If I were you, I'd add ctrl to the panel, on top of the picture box. This will make it easier to calculate offsets relative to the panel.
I have a Windows Forms application with a control. The control consists of a chart panel with a canvas on which I paint. What I would like to do is to programmatically mouse drag the panel so that I have a specific distance between the right edge of the canvas and the last item painted on the canvas. I have tried two approaches. The both work in the sense that the panel is dragged as desired BUT I cannot seem to be able to get the precision of movement I desire. I coded a mouse simulator and have tried two approaches.
Approach 1:
if(this.ChartControl.ChartPanel.CanFocus)
{
// ... Focus the chart panel to be adjusted.
this.ChartControl.ChartPanel.Focus();
// ... Move cursor to lastBarScreenCoordinates on the chart panel to be adjusted.
Cursor.Position = new Point(lastBarScreenCoordinates.X, lastBarScreenCoordinates.Y);
MouseSimulator.SetMouseDragThresholds();
// ... Move chart panel to required position.
MouseSimulator.LeftMouseButtonDown(lastBarScreenCoordinates.X, lastBarScreenCoordinates.Y);
MouseSimulator.MouseMove(lastBarScreenCoordinates.X-positionShift,
lastBarScreenCoordinates.Y);
MouseSimulator.LeftMouseButtonUp(lastBarScreenCoordinates.X-positionShift,
lastBarScreenCoordinates.Y);
MouseSimulator.ResetMouseDragThresholds(_cx_default, _cy_default);
// ... Redraw the chart panel.
this.ChartControl.ChartPanel.Refresh();
// ... Reset cursor to its starting position.
Cursor.Position = new Point(startingCursorX, startingCursorY);
}
Approach 2:
if(this.ChartControl.ChartPanel.CanFocus)
{
// ... Focus the chart panel to be adjusted.
this.ChartControl.ChartPanel.Focus();
// ... Move cursor to lastBarScreenCoordinates on the chart panel to be adjusted.
Cursor.Position = new Point(lastBarScreenCoordinates.X, lastBarScreenCoordinates.Y);
MouseSimulator.SetMouseDragThresholds();
// ... Move chart panel to required position.
MouseSimulator.LeftMouseButtonDown(lastBarScreenCoordinates.X, lastBarScreenCoordinates.Y);
Cursor.Position = new Point(lastBarScreenCoordinates.X-positionShift,
lastBarScreenCoordinates.Y);
WindowsCommunication.SendMessage(this.ChartControl.Handle, 0x200, IntPtr.Zero,IntPtr.Zero);
MouseSimulator.LeftMouseButtonUp(lastBarScreenCoordinates.X-positionShift,
lastBarScreenCoordinates.Y);
MouseSimulator.ResetMouseDragThresholds(_cx_default, _cy_default);
// ... Redraw the chart panel.
this.ChartControl.ChartPanel.Refresh();
// ... Reset cursor to its starting position.
Cursor.Position = new Point(startingCursorX, startingCursorY);
}
I am using SendInput for simulating mouse clicks. Here is sample left mouse button down code ...
public static void LeftMouseButtonDown(int x, int y)
{
INPUT mouseInput = new INPUT();
mouseInput.type = SendInputEventType.InputMouse;
mouseInput.mkhi.mi.dx = CalculateAbsoluteCoordinateX(x);
mouseInput.mkhi.mi.dy = CalculateAbsoluteCoordinateY(y);
mouseInput.mkhi.mi.mouseData = 0;
mouseInput.mkhi.mi.time = 0;
mouseInput.mkhi.mi.dwFlags = MouseEventFlags.MOUSEEVENTF_LEFTDOWN;
SendInput(1, ref mouseInput, Marshal.SizeOf(new INPUT()));
}
And I calculate normalized absolute coordinates for the mouse as follows ...
private static int CalculateAbsoluteCoordinateX(int x)
{
return ((x * 65536) + GetSystemMetrics(SystemMetric.SM_CXSCREEN) - 1) /
GetSystemMetrics(SystemMetric.SM_CXSCREEN);
}
So here are the precision issues. If I use Approach 1 (mouse move), the measured distance between the last item painted and the right edge of the canvas is different from what I set in positionShift and the cursor position difference does not equal positionShift. I initially thought it was due to pointer ballistics issues so I tried using Approach 2. Approach 2 does give me precision in pointer positioning but I am still having difficulty in that the panel moves but the distance between the last bar painted and the right edge of the canvas does not equal the positionShift amount as it should. It always seems to be off. I have been working on this for a long time now and am at my wits end. I am not sure what is going on here. How to improve the precision in my canvas drag by simulated mouse drag?
Well what you can do is this, First of all I believe the SendInput API allows for an AbsoluteValue flag so there is no need to calculate those values which may be the issue but most likely not.
Although I am curious as to why you are using a Mouse Drag opperation for this. It seems like all you want to do is reposition the canvas on every draw by some specified amount. if this is the case why not just set it explicitly on the canvas itself. Also it is unclear if you are using pure WinForms or WPF. The unclear bit being Canvas which I am fairly certain is only usable with WPF enabled windows.
That being said
WPF fix,
Depending on the Object containing the canvas just set its margin appropriately for the situation, since I do not know the data you are working with I cant say much about that. But this is a relatively simple idea so let me know if that works, it should give you, at least close too, a pixel perfect alignment.
WinForms,
Just do the above for the "Canvas" object you were talking about, or use absolute coordinates of the object to move it around.
If you could supply a sample of what you were working on looked like roughly maybe we could have a better idea of what you mean.
I'm trying to get the maximum amount a scrollviewer can scroll in the vertical and horizontal direction but I need to be doing this in a layout updated callback. This is what I'm currently doing:
viewer.ScrollToRight( );
doublehmax = viewer.HorizontalOffset;
viewer.ScrollToBottom( );
double vmax = viewer.VerticalOffset;
But this casues an error: "Unhandled Error in Silverlight 2 Application Layout cycle detected. Layout could not complete."
Is there a way I can get the max horizontal and vertical offsets of the scroll view area reliably even after window resizes and the like?
use ScrollableWidth and Scrollableheight
I think what you want is the ExtentWidth and ExtentHeight, right? You want the max size of what's inside the ScrollViewer.
To get max offset you need to check the ScrollViewer's ScrollBar.
ExtentWidth and ScrollableWidth is not what you want, they include the ScrollViewer's ViewportWidth (same with height).
Here's a ScrollViewer extension method to get a ScrollBar reference (because it's part of ScrollViewer's template):
public static ScrollBar GetScrollBar(this ScrollViewer sv, Orientation orientation) {
if(orientation == Orientation.Vertical) {
return sv.Template.FindName("PART_VerticalScrollBar", sv) as ScrollBar;
}
return sv.Template.FindName("PART_HorizontalScrollBar", sv) as ScrollBar;
}
Then to get the maximum:
var hScrollBar = viewer.GetScrollBar(Orientation.Horizontal);
double maxOffset = hScrollBar.Maximum;
(This is w/ WPF not Silverlight but googling landed me here so not sure if Template names are the same but you should get the idea)
I am working on extending the Microsoft resize Adorner example and need to be able to reposition the element after say the bottom left drag handle has been dragged.
So if I have a textbox of say 150 wide, 35 high postitioned on my form, and the bottom left drag handle changes the width to 200 wide, the right hand of the text box remains unchanged but the left hand edge moves to the left.
So I need to know the top left coordinates of the UIElement. I have tried Canvas.GetLeft and Canvas.GetTop but they return NaN which is confusing.
I just tried VisualTreeHelper.GetOffset which does return an offset but when you try and use it in the arrange method of the element it disappears, presumably as the values in the offset are too high.
In the days before Wpf the coordinate system was quite simple, wpf has overcomplicated things I think.
And if someone just wants the control's screen coordinates:
Point targetLoc = targetCtrl.PointToScreen(new Point(0, 0));
(this doesn't match the thread's description, but it does match the title. Figured it might help people coming in off search results)
You can transform coordinates of the UIElement to its parent. In your case it's a form. Here is an example of a method that returns coordinates of a visual:
private Point GetPosition(Visual element) {
var positionTransform = element.TransformToAncestor(MyForm);
var areaPosition = positionTransform.Transform(new Point(0, 0));
return areaPosition;
}