Win Form Calculator: Buttons 0 - 9 Event handler to perform repetitive task

Question

I have a win form UI that looks like a typical calculator. Naturally I do not want to rewrite the same logic for every single numeric button(0-9). I want to be able to know which button was clicked so I can perform calculations based on it's text property. Should I just make a method that accepts the button object as a parameter to promote code reuse? Is there a better way? I would like to hear how more tenured Win Form app devs would handle this. I am attempting to keep my logic out of the UI.

Thanks!

Answer 1

When specifying the event handler, you can register the same function to handle multiple events (if in VS.Net, go to properties, select the events section (lightning button), click on the drop down for Click). This way you will write one event handler function to handle all the buttons.

Example (C#) if button creation and event registration are done in code:

public void digitButtons_Click(object sender, EventArgs eventArgs) {
    if(sender is Button) {
        string digit = (sender as Button).Text;
        // TODO: do magic
    }
}

public void createButtons() {
    for(int i = 0; i < 10; i++) {
        Button button = new Button();
        button.Text = i.ToString();
        button.Click += digitButtons_Click;
        // TODO: add button to Form
    }
}

Answer 2

That is exactly what I was looking for. Thanks a ton!

Answer 3

The typical signature of an event handler is void EventHandler(object sender, EventArgs e). The important part there is the object sender. This is the object that fired the event. In the case of a Button's click event, the sender will be that Button.

void digitButton_Click(object sender, EventArgs e)
{
    Button ButtonThatWasPushed = (Button)sender;
    string ButtonText = ButtonThatWasPushed.Text; //the button's Text
    //do something

    //If you store the button's numeric value in it's Tag property
    //things become even easier.
    int ButtonValue = (int)ButtonThatWasPushed.Tag;
}

Answer 4

One more thing. Anyway to group the digit buttons so they can be differentiated from other buttons on the form?

Thanks again.