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How to PgUp/PgDn with SendKeys to a foreground textbox

I am trying to page up/down the contents of a simple textbox control in a simple Windows Form on NET 6.0, but something is wrong. Textbox shortcuts are enabled (probably why SendKeys.SendWait("^a"); works) and readonly is false.
I have a method (not on the UI thread) that I call to SendKeys.SendWait("{PgUp}"); to the foreground app (which is both the key sender and textbox (with focus) receiver.
If I type PgUp on the keyboard, the textbox pages up as expected.
If I SendKeys.SendWait("^a");, the textbox selects all text as expected.
If I Sendkeys.SendWait("{PgUp}");, the textbox adds a blank line to the bottom of the text.
From this I conclude that my code is working because it sends "^a" and the textbox receives it and selects all text. But somehow the textbox does not handle the "{PgUp}" key, even though it does when the PgUp key is sent by the keyboard.
I've read easily a dozen articles and posts on the web and SO that talk about paging using scrolling events, positioning the caret and then scrolling to the caret, and so on. But none of them say anything about why SendKeys(^a) and keyboard PgUp would work but SendKeys.SendWait("{PgUp}") would fail.
Can anyone tell me what I'm doing wrong and maybe what I need to do (or read) to fix it? Thank you
UPDATE: Jimi asked for some code, so here is the code that I use to send the ^a and the {PgUp} keys. I know this is not on the UI thread because it is executed from a voice-driven recognizer thread. The app is a voice-driven app that displays content in the textbox by textbox.AppendLines calls. I was trying to PgUp and PgDn the multi-line textbox by voice as well.
When I tried to use Send (I normally use .SendWait for everything in other programs), I received the following error message:
System.InvalidOperationException: 'SendKeys cannot run inside this
application because the application is not handling Windows messages.
Either change the application to handle messages, or use the
SendKeys.SendWait method.'
It is true that my app does not intercept Windows messages. I can't figure out why the app can receive and properly process my keyboard keys, and my "^a' shortcut keys, but not the SendWait("{PgUp}") key.
internal static void
HelperPageUp() {
var keys = "{PgUp}";
keys = "^a";
SendKeys.SendWait(keys);
}
I'm starting to think that {PgUp} is never handled by a textbox or control. Instead, probably {PgUp} must be handled by logic in a case statement that converts PgUp "orders" into sets of actions that implement whatever PgUp means to the app that receives the PgUp key. So maybe I will have to add a keystroke handler to the form. Maybe something like this:
textBox1_KeyUp(object sender, KeyEventArgs e) {
// identify the special key and implement what it means
if (e.KeyCode == Keys.PageDown) {
...
e.Handled = true;
}

Yes, my thought at the end of the question was correct. The ^a was handled by the textbox because I had textbox.EnableShortcuts=true;, so the textbox handled the popular ^a shortcut. But keys like {PgUp} are a different matter; they are not included in shortcuts.
The solution was to write code to handle the {PgUp} key explicitly in the form. Here is my code that worked.
void
textBox1_KeyUp(object sender, KeyEventArgs e) {
if (e.KeyCode == Keys.PageUp) {
// page the viewport up; watch for end of content
var charIndex = textBox1.SelectionStart;
var lineIndex = textBox1.GetLineFromCharIndex(charIndex);
// move 20 lines up, but not past zero
var newLine = lineIndex - 20;
var newIndex = Math.Max(0, newLine);
// set the new anchor and scroll to it
var newAnchor = textBox1.GetFirstCharIndexFromLine(newIndex);
textBox1.Select(newAnchor,0);
textBox1.ScrollToCaret();
e.Handled = true;
}

C# + SlimDX / XInput - how to poll when button is pressed?

I need to interface with Xbox 360 controllers and my limited knowledge leaves me stuck with C#. I don't want to use XNA (and require users to have it installed) for this simple thing, so I'm using SlimDX to allow me to interface with XInput. I have been able to detect all button presses and the little program is coming along...but I need to know how to poll / know when a button is pressed, to then trigger events.
Right now I have a timer running at 10ms and it checks which buttons are pressed and behaves based on that. But let's say you press X for one second = it detects X was "pressed" 100 times because well, every 10ms, X was pressed. I want to fire up my events only when the button is pressed, and not have to depend on a timer.
Is it possible with SlimDX on C#? If so, how? If not, is there a better/lower latency XInput wrapper for C# that will do what I need?
Thanks in advance!

Create two variables to store the button's state between polls.
bool curretButtonState;//pressed == true
bool previousButtonState;
//poll each 10ms
void CheckInput()
{
currentButtonState = pollResult;
if(currentButtonState == true && previousButtonState == false)
{
//button just pressed, call code
}
if(currentButtonState== false && previousButtonState == true)//additional functionality if desired
{
//button just released, call other code
}
previousButtonState = currentButtonState;
}
Let's say it detects a button press and runs your appropriate code, then the next time it polls (10ms), since the previous state was toggled to true, and the button is still pressed, then both states will be true and it wont run the code the 2nd time. The 1st if statement will not be true again until the button is release and re-pressed.

Control input via button

I made a Tic Tac Toe game and I'm trying to add a few features.
I was used to handle the taken buttons with
button.enabled=false;
The problems is that the text on the buttons turns grey.
So I made a button click for each button:
A1_Click, A2_Click, and so on
This is my code into A1_click, and it's the same for the other buttons, the only thing that changes is "A1", "A2", and so on
Button b = (Button)sender;
if (!A1.Text.Equals(""))
{
MessageBox.Show("Not A Valid Input");
}
I get "not a valid input" when I click a button I've already clicked before, I'd just like to be able to click an another button.
I don't want to lose my turn if I click on an already taken button

Based on what I have read I think I know what you are looking for. You are looking for a way to force the user to lose a turn when they click a button that has already been taken, and you do not want to set the enabled property to false. If that is what you want, then I might have some code that could help. First if you are assigning the same click event to multiple buttons with different functions you should try something like this:
for (int i = 1; i < 10; i++)
{
string currentButtonName = "A" + i;
Control currentButton = this.Controls.Find(currentButtonName, true).FirstOrDefault();
currentButton.Click += OnGameButton_Click;
}
What this is doing is searching your form for a control that has a specified name, and since your buttons have a similar name we can easily search for them. Then we can bind a specific function to all of them so that instead of 9 functions to modify you only have 1, and you can validate that they all work the same. Here is the OnGameButton_Click() event code:
private void OnGameButton_Click(object sender, EventArgs e)
{
if (!hasGameStarted || shouldLoseTurn)
return;
// This is the current button user pressed
Button b = (sender as Button);
if (b.Name.Contains('A') && b.Enabled)
{
if (!b.Text.Equals(""))
{
MessageBox.Show("Not A Valid Input! You have lost your turn.");
shouldLoseTurn = true;
}
else
{
b.Text = currentPlayersLetter;
shouldLoseTurn = false;
}
}
}
As you can see with some flags we can monitor the game, and force the buttons to react accordingly take a look at the beginning of the function. We have to validate that the game is engaged, and that the current user has not lost their turn due to pressing the same button. From there we just need modify what you had so that if they do press the same button twice then we modify the shouldLoseTurn flag as needed.
The other approach is to just simply use the Button.Enabled property to disable the button from use. I know you do not what the button to be grayed out, but if you create your own style guide for the button you could make it how you want. This can be challenging though because you will have to modify the default style template for the button to achieve this. Here is another question that discusses just that here

Why does pressing Ctrl+"+" produce a beep in a TextBox?

I am Working with C# and Windows Forms and want to use Ctrl+"Oemplus" as a function key for my application. I use a German keyboard and this key is located 2 keys right of the letter P (that ist then "+"). Whenever I press this key in combination with Ctrl and the focus is on a TextBox I get a beep.
This also happens when I switch to an US keyboard layout (still using my German keyboard). This is then the ] key.
The same happens when pressing this key while in Internet Explorers address bar.
My question is:
Why does this key combination produce a beep in a TextBox.
How can I avoid the beep?
Thanks for any efforts you put on this.
Update:
I tried it on an US/Thai keyboard and get the beep as well. This happens no matter what logical keyboard layout I use (German, US, Thai).
The beep also happens in Windows Explorer in the address bar but not in the search box.

It is very unclear what you hope to happen when you press that keystroke. TextBox leaves no doubt about it, it BEEPs! because it can see that the user is trying to do something special but it doesn't know exactly what. Good reason to beep you. Solution is to implement magic, in the //.. comment in this next snippet. With the extra code to stop the beep at the end:
private void textBox1_KeyDown(object sender, KeyEventArgs e) {
if (e.KeyData == (Keys.Control | Keys.Oemplus)) {
// Invoke magic
//...
// Magic is done now:
e.Handled = e.SuppressKeyPress = true;
}
}

What I believe is happening is that the key combination is not allowed for the Textbox, therefore you are getting the error. You can test for the Key Combination by this code( using the right bracket key in EN Windows) it is using SuppressKeyPress to prevent the Key Combination from being passed to the underlying control to prevent the beep.
private void textBox1_KeyDown(object sender, KeyEventArgs e)
{
if (ModifierKeys == Keys.Control)
if (e.KeyValue == 221) // You may need to determine this value for your keyboard layout.
{
textBox1.Text += " + "; // Handle the Key combination.
e.SuppressKeyPress = true; // Prevents key from being passed to underlying control
}
}

After some time I came back on this. What I found unsatisfying with the previous solution was that every TextBox would need that handling for every 'beeping' key I use for something else. Sure I could subclass the TextBox but still I would have two places to change for every key with this behavior (the handling and the beep suppression).
Actually I use Ctrl+'+' as a command key. I did this with a global keyboard hook because the action should be available on and impact all forms.
Instead I handle this now in a base form using the following code:
// Avoid beep on Ctrl+'+' in TextBox.
protected override bool ProcessCmdKey(ref Message msg, Keys keyData)
{
Keys key = keyData & Keys.KeyCode;
bool alt = keyData.HasFlag(Keys.Alt);
bool shift = keyData.HasFlag(Keys.Shift);
bool control = keyData.HasFlag(Keys.Control);
if (key == Keys.Oemplus && !shift && control && !alt)
{
// Perform the action for Ctrl+'+'
return true;
}
return base.ProcessCmdKey(ref msg, keyData);
}
For me this seems the "correct" Position and way to handle a command key. The beep is gone without any additional handling and I don't have to worry if additional command keys produce a beep or not.
When the form had a menu or toolbar this would be handled automatically by the shortcut defined for the menu item. But my forms don't have a menu or toolbar.

Ignore Single Click in WPF

I have a user control wherein I would like to do something different in the case of a single click vs. double click. I'm handling mouseLeftButtonDown event as such:
private void cueCanvas_MouseLeftButtonDown(object sender, MouseButtonEventArgs e)
{
switch (e.ClickCount)
{
case 1:
{
cueCanvas.Focus();
e.Handled = true;
_mouseStartPoint = Mouse.GetPosition(null);
break;
}
case 2:
{
double pos = Mouse.GetPosition(cueCanvas).X;
TimeSpan time = ConvertFromPosition(pos);
AddNewEvent(time);
e.Handled = true;
break;
}
}
}
The problem is that WPF doesn't really care how many times you've clicked the mouse so I get the first click event even though I'm about to get a second one (in the case of a double-click). Has anyone come up with a way to work around this? I realize I could try to get clever and set some timers such that the first click gets "canceled" in the event that the second one comes in (I realize this is what the framework would be doing anyway). If that's the only answer, does anyone know how we query the system for the appropriate click delay?

To my knowledge, there's really no way to do this. The problem is that you're fighting reality. :-) In reality, there are 2 clicks to a double-click. You want single click to be ignored if quickly followed by a double-click.
You'll have wait a short interval to see if it's followed by a second click. You can query for that interval using the SystemInformation class from WinForms, or just call the Win32 API directly.