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How do I add a textblock dynamically to a page?

I'm just learning how to make universal apps for windows 10. Most of the tutorials show you how to work with XAML and how to assign functions to elements when you click on them but I couldn't find a way to make a new control appear when I click a button.
I'm making a note taking application. I've designed most of the stuff that I need. Now I want whenever I click a button to create a new textblock where the user can write their note.
//Create a new note when clicking the add button
private void newNoteBtn_Click(object sender, RoutedEventArgs e)
{
TextBox newNote = new TextBox();
newNote.Text = "Enter your text";
}
This is the code that runs when the button is clicked. When I run the application nothing happens. I think I have to put the new textbox in some kind of Grid or something.
Most of the tutorials are really old or mention windows forms and use some sort of this.Controls.Add(newNote); but Visual studio doesn't give me the Controls.Add option. I've also created a <Grid x:Name="notes"></Grid> which I thought I could use as a placeholder for the notes that are being created but I can't access the Grid element through the code.

Container Controls like Grid have Children property so you should use Childern like this:
TextBox newNote = new TextBox();
newNote.Text = "Enter your text";
notes.Childern.Add(newNote);

When defining
<Grid x:Name="notes"></Grid>
in XAML on the page, you be able to use notes as the identifier to access this Grid from the page's code behind:
notes.Children.Add(newNote);

how to insert the value of dynamically generated run time textbox

I have one table into database named card_details which has two fields card_number, card_value. I want to create some asp.net application where user enter the value of card number in textbox and automatically fetch the respected card value into another textbox.
Suppose user has more than one card then we have to give one button (Add More Card). After clicking this button its automatically generate two textboxes on runtime as mentioned my requirement where user can put the card number and its finds the value in another textboxes. And its also sum the card values(Gross Total) and show into another textbox.

$('#idTextbox').val('type texh whatever you want');
idTextbox: id of the dynamic textbox.
Is this, what you want to know.

Add a Panel to your page and then in the code behind of your Button use this to add controls dynamically:
TextBox dynamicTxtBox = new TextBox();
dynamicTxtBox.Text = "(enter text)";
dynamicTxtBox.ID = "dTxtBox";
Button dynamicBtn = new Button();
dynamicBtn.Click += new System.EventHandler(dynamicBtn_Click);
Panel1.Controls.Add(dynamicTxtBox);
Panel1.Controls.Add(dynamicBtn);
private void dynamicBtn_Click(Object sender, System.EventArgs e)
{
//your code here
}
Similarly you can add another TextBox as your requirement is two boxes.

Center Checkboxes in Table Layout Panel

I'm trying to center my checkboxes in a TableLayoutPanel, but they always end up looking left-aligned due to the nature of the checkbox control. See picture below:
I want each rows checks to be left-aligned, but for it to appear more centered. Something like the following:
I've checked around online, and I can center the checkboxes by setting AnchorStyles.None which is not what I want, because then the checkboxes are not aligned. I have them set to Dock.Fill so you can click anywhere in the cell to activate the checkbox.
I'm currently just padding my table to achieve a similar effect, but it's by far not an acceptable solution long-term. Also, padding the cells will line break the checkbox text without taking up all the available space on the row (since some of the row is being eaten by padding). The same goes for using a spacer-cell on the left of the table, not an ideal solution.
Does anyone have any ideas? Thanks!

This may work for you:
Set all the ColumnStyles of your TableLayoutPanel as .SizeType = SizeType.AutoSize.
Set your TableLayoutPanel.AutoSize = true and TableLayoutPanel.AutoSizeMode = AutoSizeMode.GrowAndShrink;
Add this code to center your checkboxes (as well as your TableLayoutPanel) dynamically:
//SizeChanged event handler of your tableLayoutPanel1
private void tableLayoutPanel1_SizeChanged(object sender, EventArgs e){
//We just care about the horizontal position
tableLayoutPanel1.Left = (tableLayoutPanel1.Parent.Width - tableLayoutPanel1.Width)/2;
//you can adjust the vertical position if you need.
}
UPDATE
As for your added question, I think we have to change some things:
Set your CheckBox AutoSize to false. The solution before requires it to be true.
Add more code (beside the code above):
int checkWidth = CheckBoxRenderer.GetGlyphSize(yourCheckBox.CreateGraphics(),System.Windows.Forms.VisualStyles.CheckBoxState.MixedNormal).Width;
//TextChanged event handler of your CheckBoxes (used for all the checkBoxes)
private void checkBoxes_TextChanged(object sender, EventArgs e){
UpdateCheckBoxSize((CheckBox)sender);
}
//method to update the size of CheckBox, the size is changed when the CheckBox's Font is bolded and AutoSize = true.
//However we set AutoSize = false and we have to make the CheckBox wide enough
//to contain the bold version of its Text.
private void UpdateCheckBoxSize(CheckBox c){
c.Width = TextRenderer.MeasureText(c.Text, new Font(c.Font, FontStyle.Bold)).Width + 2 * checkWidth;
}
//initially, you have to call UpdateCheckBoxSize
//this code can be placed in the form constructor
foreach(CheckBox c in tableLayoutPanel1.Controls.OfType<CheckBox>())
UpdateCheckBoxSize(c);
//add this to make your CheckBoxes centered even when the form containing tableLayoutPanel1 resizes
//This can also be placed in the form constructor
tableLayoutPanel1.Parent.SizeChanged += (s,e) => {
tableLayoutPanel1.Left = (tableLayoutPanel1.Parent.Width - tableLayoutPanel1.Width)/2;
};

Instead of having the checkboxes in cells, having each one inside a panel all inside a groupbox will allow the checkboxes to fill each panel and have a click able area around them. then with the groupbox dock set to fill and the panels' anchors set to top,bottom they all stay centered.

Cannont Update control in WPF custom control

I have created a custom control which holds a button in it. The button is styled, so as to hold a grid with two rows, an image in the first and a TextBlock in the second. I have written an Event Handler for the custom control. When the mouse enters the path of the object the MouseEnter event fires, where I try to change the TextBlock's FontSize and Foreground color, however the control does not update. In contrast, I have tried to modify an regular TextBlock's(not part a custom control and controltemplate) properties, and they update correctly, on the fly.
What am I missing here?? Here is the code for the event handler:
private void ThemeButton_MouseEnter(object sender, MouseEventArgs e)
{
InitializeProperties();
TextElement.FontSize = 16;
TextElement.Text = "new text";
TextElement.Foreground = Brushes.Red;
TextBlock element = MainWindow.FindChild<TextBlock>(MainWindow.StartWindow, "textField");
element.Text = "new text for regular textblock";
element.Foreground = Brushes.Red;
}
InitializeProperties is a methid that initializes TextElement(typeof TextBlock) and ImageElement(typeof Image) properties. They are not null. The properties are just regular .NET properties.

wow...my problem actually was that the Properties(TextElement and ImageElemenet) were pointing to the elements in the template(custom control) and not to the elements that actually got rendered in the Window...
Remember, when searching for elements, always start your search after rendering is complete(i.e. start search when a user action fires an event or something similar) so that the elements get into the Visual Tree!!

how can i achieve this in c#

i'm developing a windows form application.in the form, the left part is a tree menu, and the right part is show area. how can i change the show area according to what i click on the tree menu.
(source: 126.net)
i use treenode class to implement treemenu like this:
System.Windows.Forms.TreeNode treeNode27 = new System.Windows.Forms.TreeNode("basic operation");
what i try to do is use several panels. each panel bounds to a menu item. by setting the visible property, i can achieve that goal. but it is too inconvenient.especially when i try to design each panel.
any good suggestion?

You could design each "Panel" as a new User Control. That way you can design all of the "panels / areas" on their own, independently of the Main Form.
On your Main Form, create a single panel for the right hand side area and add all of the controls to that one panel.
Then when the TreeNode selection event happens you can set all the user controls to .Visible = false; except for the one you are showing and set that to .Visible = true; and .Dock = DockStyle.Fill;

What you need is an event handler that will be called at the time of the user clicking the treeview (Use TreeView from the toolBox). You can do that by selecting the treeview on the design page and under properties click on Events. Then select NodeMouseDoubleClick or NodeMouseClick depending upon what you want. Below is a code that captures the values selected...Enjoy...;)
private void treeView1_NodeMouseDoubleClick(object sender, TreeNodeMouseClickEventArgs e)
{
if (treeView1.SelectedNode.Level == 2)
{
//text on the first level
string text = treeView1.SelectedNode.Text;
}
else if (treeView1.SelectedNode.Level == 1)
{
//text on the second level
string text = treeView1.SelectedNode.Text;
}
}