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In this lecture we are going to create the button click event a click event is the activity that someone

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performs.

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For example when you click a button that is regarded as an event.

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So we're going to write a piece of code that does something when the event occurs.

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So this is the design for our calculator.

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The moment and the moment if I click on it if I run the program let me click start to run the program

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for run the program and click on any of the buttons.

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Nothing happens.

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None of the the text or what's on the button is displayed in the result.

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So we're gonna change that using a click event.

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Gonna write some code behind that.

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So to begin click on the button.

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I'll start with the number one button and in the property window we click on the event.

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This is event so an event basically something that happens to an object.

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So one of the events here is a click event.

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So we need to define the event.

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So by giving it a name so I'm gonna call it click

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on the score button.

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So I've given it a name on the com button so to access the code behind this I just click on this and

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to open up the code behind and also tells me see where the cup where this is flashing tells me any code

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I need to write for this button click event I need to write it in here.

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So this method an interactive here some someone write a piece of code.

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So what I'm going to do I'm going to say I'm gonna reference the text box which is called result.

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I call the result box.

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You can see the intelligence is giving me guides.

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I just click that does the name and it's a text box.

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I'm gonna say dot text

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and make it up in case.

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Okay.

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So as a result dot text I'm going to set that to a course to the result box

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dot takes

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and I'm going to add a concatenation operator concatenation means you something that will use to add

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things together it's going to be a plus operator and I'm going to inside the parentheses I'm going to

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include the number one

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so save this.

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Now I run the code.

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You should see no one should appear on the calculator.

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So if I click what you can see no one appears.

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Notice it appears next to the 0 0 will sort out later.

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You can see none of the other keys is working just the number one.

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All right.

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Clear that.

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So what I'm going to do I'm going to combine all these functions.

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This method here is click event.

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I'm going to go back to our form designer and I'm going to copy this and paste it for the other buttons.

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The numerical buttons so I'll start with the zero for us and come here paste and go to that I paste

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and go to

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paste three paste and so on for paste five paste six paste seven

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and paste eight paste nine paste.

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So they were all reference the same click event.

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So if I run this now I'll just save all that and I'll run it.

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I should be able to click on a C seven.

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I'll tell you what I didn't do.

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So at the moment all the all the buttons seem to be referencing this one.

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So we want to change that.

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And what we're going to do we going to implement a piece of code here and possum po.

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They send the object references the button click event.

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So we're going to create another code here.

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Also type in button which is built in and then we give it a name

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a button object and we going to set the value to close to the button which is button and then the sender

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the sender here references to click event.

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I'm going to call the sender All right.

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And they're Will here would change the output so that and important that is clicked it will display

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the text on the button.

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So to do that we're going to replace this one with

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with the button that we create here.

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So to be button dot text that means it would display the text on any of the button that is clicked.

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So I'll save that a run the code.

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Now any of those buttons when clicked you can see the same seven even though the zero that ignore the

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zero for now we will sort that out later.

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Eight nine.

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We're just trying to make sure all the buttons are showing one two three in to zero on the dot.

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So everything is working.

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We'll implement different click event for the operators and we'll figure out a code how to implement

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the clever button.

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So that's set for this lecture at least we've implemented a button click event.

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We've got all the buttons the text on the button now displaying on the results screen when the button

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is clicked.

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Thanks so much for watching.

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Take care.

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Bye for now.