Develop Reference

using string as control id in C# ASP.NET

i have a page with 2 textbox items and a button
textbox1 contains a word , and textbox2 is empty
now i want to put content of TextBox1.Text in TextBox2.Text with button click,
i tried:
protected void Button1_Click(object sender, EventArgs e)
{ Page.FindControl("TextBox2").Text = TextBox1.Text; }
this code don't work ,how to make this work?

TextBox textbox2= (TextBox)FindControlRecursive(Page, "TextBox2");
try using this, referencing this article

you need to define it first then apply properties
protected void Button1_Click(object sender, EventArgs e)
{
TextBox textBox2 = (TextBox)Page.FindControl("TextBox2");
textBox2.Text = TextBox1.Text;
}

How to make buttons display their text in a label using one click event

Is it possible to have a click event that displays the text of buttons in a label in c#.
I want to write single code that will work for:
public button1_Click(Object sender, EventArgs e){
label1.Text = button1.Text;
}
public button2_Click(Object sender, EventArgs e){
label2.Text = button2.Text;
}

Is this what you are looking for?
On a button click, you can handle setting text as below
you can add two buttons. Have same click events for both buttons.
Take help of parameter sender to get which button is clicked.
code (sender as Button) gives you all the details of clicked button.
private void button1_Click(object sender, EventArgs e)
{
this.label1.Text = (sender as Button).Text;
}

1) Add a Button and a Label to the blank Form in a new project.
2) Double-click the Button.
This will generate the following Click event method...
private void button1_Click(object sender, EventArgs e) {
}
3) Put the following line of code in the button1_Click method body:
label1.Text = button1.Text;
4) Profit.

How to change text of Label while typing in TextBox

Please I'm new to C#, I created a textBox and a label. What i am expecting is, if I type a value into the textBox, I want it to display on the label and if I change the value it should also change immediately on the label.
it work with the code below and i press enter key
private void textBox1_KeyDown(object sender, KeyEventArgs e)
{
if (e.KeyCode == Keys.Enter)
{
label1.Text = textBox1.Text;
}
}
But I want it without press Enter/Return Key on keyboard.
Thanks for understanding

This works for VisualStudio
Select your TextBox in the Designer, go to the it's properties and click on the events (teh icon with the lightning). Then make a double click on the event that is called: TextChanged.
This creates a new function, that will always be called when the text of your TextBox changes. Insert following code into the function:
private void textBox1_TextChanged(object sender, EventArgs e)
{
TextBox tb = sender as TextBox;
label1.Text = tb.Text;
}
That's it.

label.DataBindings.Add("Text", textBox, "Text");

textbox KeyDown/Up/Press events may help.
For example
private void textBox1_KeyDown(object sender, KeyEventArgs e)
{
label1.Text += e.KeyData.ToString();
}

one Click event for multiple buttons with Text property

I want to make a click event for a bunch of buttons. The problem is that I want to use the button's Text, and pass it to a function. Now the click event is passed a object sender. When I tried changing that to Button sender, it gave errors. But I don't know how else I can work with the senders Text.
Here is the normal code, which gave a single error:
private void guess_Click(object sender, EventArgs e)
{
guess(sender.Text);
}
I changed it to this, which gave errors:
private void guess_Click(Button sender, EventArgs e)
{
guess(sender.Text);
}
Question:
How can I work with the Button's Text property within this click event, which is a single click_event for multiple buttons?

Step 1: You need to subscribe to the Button Click event of all your buttons to the same EventHandler. so that button click on all your Buttons will fire the same `Event Handler.
Step 2: You need to cast the object sender into Button and then access its Text property to get the Button Text.
Try This:
button1.Click += new System.EventHandler(MyButtonClick);
button2.Click += new System.EventHandler(MyButtonClick);
button3.Click += new System.EventHandler(MyButtonClick);
private void MyButtonClick(object sender, EventArgs e)
{
Button btnClick = (Button)sender ;
guess(btnClick.Text);
}

Cast sender to type button.
Example:
private void guess_Click(object sender, EventArgs e)
{
guess(((Button)sender).Text);
}

You need to cast the sender object to the Button type and use that:
private void guess_Click(object sender, EventArgs e)
{
Button senderBtn = senderBtn as Button;
if(senderBtn != null)
{
guess(senderBtn.Text);
}
}

How to select all text in Winforms NumericUpDown upon tab in?

When the user tabs into my NumericUpDown I would like all text to be selected. Is this possible?

private void NumericUpDown1_Enter(object sender, EventArgs e)
{
NumericUpDown1.Select(0, NumericUpDown1.Text.Length);
}
(Note that the Text property is hidden in Intellisense, but it's there)

I wanted to add to this for future people who have been search for Tab and Click.
Jon B answer works perfect for Tab but I needed to modify to include click
Below will select the text if you tab in or click in. If you click and you enter the box then it will select the text. If you are already focused on the box then the click will do what it normally does.
bool selectByMouse = false;
private void quickBoxs_Enter(object sender, EventArgs e)
{
NumericUpDown curBox = sender as NumericUpDown;
curBox.Select();
curBox.Select(0, curBox.Text.Length);
if (MouseButtons == MouseButtons.Left)
{
selectByMouse = true;
}
}
private void quickBoxs_MouseDown(object sender, MouseEventArgs e)
{
NumericUpDown curBox = sender as NumericUpDown;
if (selectByMouse)
{
curBox.Select(0, curBox.Text.Length);
selectByMouse = false;
}
}
You can use this for multiple numericUpDown controls. Just need to set the Enter and MouseDown Events

I was looking around i had the same issue and this Works for me, first select the Item and the second one selects the Text, hope it helps in future
myNumericUpDown.Select();
myNumericUpDown.Select(0, myNumericUpDown.Value.ToString().Length);

I created an extension method to accomplish this:
VB:
<Extension()>
Public Sub SelectAll(myNumericUpDown As NumericUpDown)
myNumericUpDown.Select(0, myNumericUpDown.Text.Length)
End Sub
C#:
public static void SelectAll(this NumericUpDown numericUpDown)
numericUpDown.Select(0, myNumericUpDown.Text.Length)
End Sub

I had multiple numericupdown box's and wanted to achieve this for all. I created:
private void num_Enter(object sender, EventArgs e)
{
NumericUpDown box = sender as NumericUpDown;
box.Select();
box.Select(0, num_Shortage.Value.ToString().Length);
}
Then by associating this function with the Enter Event for each box (which I didn't do), my goal was achieved. Took me a while to figure out as I am a beginner. Hope this helps someone else out

For selecting all text by mouse click or by Tab button I use:
public frmMain() {
InitializeComponent();
numericUpDown1.Enter += numericUpDown_SelectAll;
numericUpDown1.MouseUp += numericUpDown_SelectAll;
}
private void numericUpDown_SelectAll(object sender, EventArgs e) {
NumericUpDown box = sender as NumericUpDown;
box.Select(0, box.Value.ToString().Length);
}

Try
myNumericUpDown.Select(0, myNumericUpDown.Value.ToString().Length);