Develop Reference

WPF Scrollviewer shrink height, bring element into view

First off, the title might not make much sense. Suggestions for changing it are appreciated.
I am clicking into a TextBox that is inside a ScrollViewer. When that happens, the ScrollViewer will shrink in height (from the bottom up), it doesn't scroll at all, and some controls near the bottom of the viewport get covered up (cause the viewport is now smaller). If the TextBox gets covered up, I need to scroll such that it is still visible.
I have checked several SO questions, and none seem to capture my problem. This one is close, but I don't have a canvas to work with. Also, given my specific scenario, I cannot use Dispatcher to wait for the UI to load, and then use BringIntoView().
The TextBox's share an event, TextBox_GotFocus,
TextBox_GotFocus(object sender, RoutedEventArgs e)
{
myScrollViewer.Height = 400; //used to be 600
//if sender was in the 401-600 range, bring it into view
}
How do I scroll the ScrollViewer only if the entered TextBox is now hidden after the height change?

No thanks to the random downvote, but I managed to figure a roundabout way to do this.
TextBox_GotFocus(object sender, RoutedEventArgs e)
{
FrameworkElement element = sender as FrameworkElement;
//Get the distance from the top and bottom of the ScrollViewer
double offsetTop = element.TranslatePoint(new Point(), myScrollViewer).Y;
double offsetBottom = myScrollViewer.Height - offsetTop;
//Get total height needed to show the whole element
double height = 200 + element.Height;
//If the control would be hidden...
if (offsetBottom < height)
{
//Scroll down the difference
double change = myScrollViewer.VerticalOffset + (height - offsetBottom);
myScrollViewer.ScrollToVerticalOffset(change);
}
myScrollViewer.Height = 400; //used to be 600
}

how to get the fontsize of a certain line in a richtextbox in c# using winforms

I have 2 comboboxes for the font and the fontsize. When I click them it changes the font size or the font in my richtextbox. Now I want it to work like in word. If the line you just moved to is in a different font or size. It should detect that and change the comboxes to match the font and size of the current line. Somoeone else asked this same question and got a result which didn't work for me. It was as follows
private void richTextBox1_SelectionChanged(object sender, EventArgs e)
{
MessageBox.Show("we got here"); // this is my added part to let me know if the code is even getting executed. It is not.
richTextBox1.SelectionStart = 1;
richTextBox1.SelectionLength = 1;
comboBox1.Text = richTextBox1.SelectionFont.ToString();
comboBox2.Text = null;
comboBox2.Text = richTextBox1.SelectionFont.Size.ToString();
}
I held out hope that it was my answer but I could not see how SelectionFont would make any difference when nothing was selected. Also the richTextBox1_SelectionChanged event seems to not be being called when I move through the document with the up/down arrows. The problem is not with the comboboxes, the problem is that as I arrow through my document I need to be able to know what font and size it is at the caret position so it can fire an event to change the combo boxes to match.

The code that you are using will always make the selection from character at index 1 and are of the length 1. instead for that you need to use which will give you the the following code without specifying the selection(so it will take the selection from the ritchTextBox).
string fontName = richTextBox1.SelectionFont.Name;
float fontsize = richTextBox1.SelectionFont.Size;

You should save the values for the new comboBox position temporarily in variables, otherwise if you do it directly
comboBox1.SelectedIndex = comboBox1.FindStringExact(richTextBox1.SelectionFont.Name);
the comboBox1_SelectedIndexChanged event will be immediately called and could affect the results.
So just try:
private void richTextBox1_SelectionChanged(object sender, EventArgs e)
{
int comboBox1Index = comboBox1.FindStringExact(richTextBox1.SelectionFont.Name);
int comboBox2Index = comboBox2.FindStringExact(richTextBox1.SelectionFont.Size.ToString());
comboBox1.SelectedIndex = comboBox1Index;
comboBox2.SelectedIndex = comboBox2Index;
}

I adapted Sujith's solution and half of Markus's solution and came up with the following which works just fine for me:
Private Sub Description_SelectionChanged(sender As Object, e As EventArgs) Handles Description.SelectionChanged
Dim fontName As String = Description.SelectionFont.Name
Dim fontSize As Single = Description.SelectionFont.Size
tbSelectFont.Text = fontName
tbSelectSize.Text = fontSize
End Sub

In form numberpad C#

I would like to add an in form numberpad to my form to make the program more touch friendly. I have multiple text boxes on this form that change focus when the enter key is pressed.
I tried SendKeys.Send("#"), but when I click the button it just changes focus to the button and does nothing inside the text box I was trying to type in.
Is there a guide or something for this? I have looked and all I can find are on screen keyboards that work outside of the form, but not inside.

Expanding a little bit on the idea from Hans Passant you could use this as a starting point.
Form
In your form add the textboxes you need and a PictureBox. The picturebox will have an image with the characters your users need to be able to type.
Set the property Image to an image file (browse for it) (or create your own)
Set the property SizeMode to AutoSize so the complete picture is shown.
Next goto the events and add an eventhandler for MouseClick.
Code
Add the following code to the handler:
private void pictureBox1_MouseClick(object sender, MouseEventArgs e)
{
// how many rows and columns do we have
// in the picture used
const int maxrows = 4;
const int maxcols = 3;
// based on each position (numbered from left to right, top to bottom)
// what character do we want to add the textbox
var chars = new [] {'1','2','3','4','5','6','7','8','9', '+', '0', '-'};
// on which row and col is clicked, based on the mouse event
// which hold the X and Y value of the coordinates relative to
// the control.
var row = (e.Y * maxrows) / this.pictureBox1.Height;
var col = (e.X * maxcols) / this.pictureBox1.Width;
// calculate the position in the char array
var scancode = row * maxcols + col;
// if the active control is a TextBox ...
if (this.ActiveControl is TextBox)
{
// ... add the char to the Text.
// add error and bounds checking as well as
// handling of special chars like delete/backspace/left/right
// if added and needed
this.ActiveControl.Text += chars[scancode];
}
}
The code is I think self explanatory. Keep in mind that no error checking whatsoever is being done here.
Result
This is what the end result will look like:

How to auto center textbox inside user control, when user control is resized?

This issue is concerning C# WinForms ... I have custom user control which basically has 3 things: A label, a text box, and a list box, all arranged vertically like this:
I have written a small Custom ControlDesigner class to prevent the user from changing the height of this user control at design time.
I also have set the textbox and listbox to anchor to left/right locations, so that when the user changes the width of the user control, these two internal controls resize beautifully.
I want to have the Label is the horizontal center as well, but anchoring that to left/right doesn't seem to work. I'm thinking I might have to written some sort of custom resize function inside the custom control designer class, which automatically places the label in the middle when the user control is resized ?
Also note that I want to label to still remain in the center when the label text is changed.
So how do I do this ?
Here is my custom control designer class till now:
public class DropDownTextBoxDesigner : System.Windows.Forms.Design.ControlDesigner
{
public override SelectionRules SelectionRules
{
get
{
SelectionRules retVal =
SelectionRules.Visible |
SelectionRules.Moveable |
SelectionRules.LeftSizeable |
SelectionRules.RightSizeable;
return retVal;
}
}
}

Write a SizeChanged of the User Control event like so:
private void UserControl1_SizeChanged(object sender, EventArgs e)
{
textBox1.Left = Width / 2 - textBox1.Width / 2;
textBox1.Top = Height / 2 - textBox1.Height / 2;
}

In the resize event, can you just set the left property of the label to center it in the container?
Label.Left = (Container.Width / 2) - (Label.Width / 2);

C# WinForms: Make panel scrollbar invisible

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.