C＃Windows表单计算器-每次单击选择文本框

Question

First of all, I'm german, 2. here is a screenshot of my calculator.. kinda weird but well i know xD

So, I'm looking for a Command:

I got 4 Textboxes, the 1st one(textBox1) for the 1. Number, the 2. one(textBox2) for the Operator (+-*/), the 3. one for the 2. Number and the 4. one for the Result

if i do:

private void button3_Click(object sender, EventArgs e)
 {
  textBox1.SelectedText += "1";
  textBox3.SelectedText += "1";

 }

or

private void button3_Click(object sender, EventArgs e)
 {
  textBox1.Text = textBox1.Text + "1";
  textBox3.Text = textBox3.Text + "1";
 }

the Number from the button I click on is shown in both textboxes now (1. and 3. one). But I want that the Number of the button i clicked on is going to be in the Textbox i selected first. So i first do select the textbox1 or textbox3 with simply clicking in it and then i click on a button(for example 1) and then the number 1 is going to be in the textbox i selected/clicked.

Answer 1

On the _Activate Event for both Textboxes, store which box was activated. Then use that in the _Clicked event:

private TextBox currentTextBox;

 // Both textboxes can use this function
private void textbox_Activate(object sender, EventArgs e)
{
        this.currentTextBox = (TextBox) sender;
}

private void button3_Click(object sender, EventArgs e)
{
         currentTextBox.Text = textBox1.Text + "1";
}

Answer 2

You can have a global variable TextBox textBoxSelected then in a event textBox1_Click and textBox3_Click set the variable. Later in button3_Click choose the textboxselected and add your logic. Try this:

TextBox textBoxSelected;
private void txtBox1_Click(object sender, EventArgs e)
{
    textBoxSelected = textBox1;
}
private void txtBox3_Click(object sender, EventArgs e)
{
    textBoxSelected = textBox3;
}
private void button3_Click(object sender, EventArgs e)
{
    textBoxSelected.Text += "1";
}

Answer 3

I can't make much sense of your question, but I have noticed an issue in your logic.

C# will be adding them as strings, which results in concatenation.

Convert the values to integers first and it will add correctly.

textBox1.Text = int.Parse(textBox1.Text) + 1;

As for you actual question, if you want to have a way of "remembering" what text box you clicked, add an event to the Click event to store the text box control that you have selected in a variable, and then use that in your logic.

Answer 4

So here are some recos: 1/ Naming convention: Use clear names that refer to the button function or the textbox content. Say for example: TextboxLeftOperand, ButtonN1, TextboxOperator, ... 2/ Use a new variable called SelectedTextbox var SelectedTextbox = new Textbox(); 3/ Add to the click event of both textboxes an assignment of the SelectedTextbox. For the left textbox: SelectedTextbox = TextboxLeftOperand // textbox1 in your case And for the right textbox SelectedTextbox = TextboxRightOperand // textbox1 in your case 4. Now all you have is work with your new variable.