Buttons and Classes. EASY for you brilliant guys.

Chris Johnson

Hi all.
I wonder if someone can advise.
I am writing a new diag program and need help on buttons using a class to change the button forecolor (and apply plc code, that bit is no problem).
I have 32 buttons on a form. The form is for turning on IO's on a PLC which I can do easily. I just want to create a graphical form that other emplyees can use. Surely the best practise is not to repeat code 32 times which we all know?

So below is a small global class I have created. How can I quickly apply this to all 32 buttons on the form?
If someone can give me an example on one button that would be superb.
What do I put in this event?

private void O16_Click(object sender, EventArgs e)

{

////What do I put here?

        }

class TwoColorButton : Button
    {
        private int stateCounter = 0;
        private Color[] states = new Color[] { Color.Black, Color.Red };

        public TwoColorButton()
            : base()
        {
            this.BackColor = states[stateCounter];
            this.Click += this.clickHandler;
        }

        protected void clickHandler(object sender, EventArgs e)
        {
            stateCounter = stateCounter == 0 ? 1 : 0;
            this.BackColor = states[stateCounter];
        }
    }

Thanks for your help in advance.

3 Replies

Know the answer? Post it — somebody with the same question will find it here.

James Axsom8y ago
Accepted answer
You asked, “I have 32 buttons on a form. The form is for turning on IO's on a PLC which I can do easily. I just want to create a graphical form that other employees can use. Surely the best practice is not to repeat code 32 times which we all know?”

If I were to read your question without the code sample below I would interpret your question as, “How do I create 32 instances of my TowColorButton Class without declaring 32 object variables, instantiating those object variables and setting their properties to define where they show up on the form”

That just can’t be what you are asking because your code sample is asking,

private void O16_Click(object sender, EventArgs e)

{

////What do I put here?

}

So, the real question must be, how do I create 32 click implementations only once.

Answer: Use an interface. Pass in a value to a context class telling the factory which implementation use.

Here is a hypothetical abstract pseudo code to get the idea of what I speak of:
private void O16_Click(object sender, EventArgs e)
{
    Context c = new Context();

    IYourInteface i = c.Factory(ImpelmentationType);
    i.DoSomething();
}

public interface IYourInterface
{
    DoSomething();
}

public class Context
{
    public IYourInterface Factory(ImplmentationType)
    {
        IYourInterface i;

        // ImplementationType would be a customized public enumeration you create

        switch (ImplementationType)
        {
            case type1:
                i = new ImplementationClass1();
                break;
            case type2:
                i = new ImplementationClass2();
                break;
            // and so on... for each implementation.

        }

        return i;
    }
}

public class ImplementationClass1 : IYourInterface
{
    public void DoSomething()
    {
        // all the code this implementation should do
    }
}
Chris Johnson8y ago
Thank you all. Very helpful.
Željko Perić8y ago
Hello,
very interesting question for me as c# beginer,
and after some search on the Internet, here is simple solution for using same button event handler for changing button foreground color of many different buttons.

In form designer, tools option, select and set buttons, and in the properties option for each button set its foreground color to BLACK.

In source code write this small button click event handler :
void Button_Click_Event(object sender, EventArgs e)
{
    Button btn = sender as Button;
    if(btn!=null)
    {
        if(btn.ForeColor == Color.Black)
            btn.ForeColor = Color.Red;
        else
            btn.ForeColor = Color.Black;
    }
}
And at the end, in the form designer, events option, for each button set above button click event handler as default button click event handler.

When app is started, by click on any button, same event handler is used for changing button foreground collor from BLACK to RED and 'vice versa'.

Original solution can be found at :

https://stackoverflow.com/questions/10739572/how-make-one-event-handler-that-applies-to-multiple-controls-in-c

All the best,
Željko Peric