How to avoid repeating code?

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I have 20 button on a winform. On each button click I want to execute the same code. I only need to pass a unique value (in my case I use the Tag field) from each button to know which button was clicked (i.e. MessageBox.Show(button.Tag.ToString()). This specific Tag-value must be transferred to the code which I can use for each button-click.
How can I do that easily without writing the same code for each button_click event?
Is there an example available which shows a solution?

What I have tried:

Now I use the same code for each button.

Posted 14-May-19 23:15pm

Member 12370240

Updated 15-May-19 4:12am

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RickZeeland · Accepted Answer · 2019-05-14T23:23:00

You can do something like this:

button1.Click += new EventHandler(Button_Click);
button2.Click += new EventHandler(Button_Click);
button3.Click += new EventHandler(Button_Click);

public void Button_Click(object sender, EventArgs e)
{
  Button btn = (Button)sender;
  if (btn.Tag == null) return;
  
  if (btn.Tag.equals("button1"))
  {
    // Do something
  }
}

Richard MacCutchan · Accepted Answer · 2019-05-14T23:25:00

Solution 2

Create a single button click event, and connect that to each button. You get the information about the sender in the parameters passed in to the event handler.

Posted 14-May-19 23:25pm

Richard MacCutchan

lmoelleb · Accepted Answer · 2019-05-14T23:26:00

Point the click handler of the button to the same method.
Visual studio helps you create a new handler, but it also allow you to select an existing.

Or you can do it through code if you get lazy. Good programmers are lazy enough to spend 4 hours programming a solution to a stupid repetitive task that would take 10 minutes to do manually :)

Pawel Wzietek · Accepted Answer · 2019-05-15T02:40:00

If you have so many buttons and want the handler to rapidly get the number of the button clicked then it may be simpler to create a button array. VB.NET does not provide a language feature for this (like VB6) but it is easy to do it manually. In the form declare

C#

Button  btnarray[];

and bind the array elements to your buttons, in the Form_Load method:

C#

btnarray=new Button[20];
btnarray[0]=Button1;
btnarray[1]=Button2;
...

Then the handler can just search the array for the matching index:

C#

int idx;
for(idx=0; idx<btnarray.Length(); idx++)
 if (sender.Equals(this.btnarray[idx]))  {break;}

phil.o · Accepted Answer · 2019-05-14T23:26:00

You can assign the same event handler (method) to all your buttons.
The Click event handler is usually defined as

C#

void button_Click(object sender, ClickEventArgs e)
{
   if (sender.Equals(this.button1))
   {
      // button1 was pressed
   }
   else if (sender.Equals(this.button2))
   {
      // button2 was pressed
   }
   // ...
   // Assuming here your buttons are named button1 .. button20.
}

In the designer, just assign the single method to the Click event of all buttons.

Dylvh · Accepted Answer · 2019-05-14T23:43:00

Solution 5

Connect to the single click event as mentioned in the previous solutions, and then try something like the following

C#

void button_Click(object sender, ClickEventArgs e)
{
    MessageBox.Show(((Button)sender).Tag.ToString());
}

Posted 14-May-19 23:43pm

Dylvh

Member 12370240 · Accepted Answer · 2019-05-15T04:12:00

I used following code to solve the problem:
I use a public function which is called from a button_click event.

public void btnclick(int i)
{
//code to execute in which I use variable i because I need to modify data table on
//specific rows. Each row matches with one button, therefor I need the correct number.
}

private void button1_Click(object sender, EventArgs e)
{
btnclick(1);
}

private void button2_Click(object sender, EventArgs e)
{
    btnclick(2);
}

And so on for every button.

How to avoid repeating code?

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