C# Xamarin Android . ButtonClick event help needed

Question

I tired doing a simple A+B addition program using xamarin but every time error system.NullReferenceException occurs for Button click.

Button button = FindViewById<Button>(Resource.Id.button1);
        button.Click += delegate {
            EditText number1 = FindViewById<EditText>(Resource.Id.editText1);
            EditText number2 = FindViewById<EditText>(Resource.Id.editText2);
            TextView res = FindViewById<TextView>(Resource.Id.textView1);
            int result = Convert.ToInt32(number1.Text) + Convert.ToInt32(number2.Text);
            res.Text = result.ToString();
        };

You have not set the activity content SetContentView (Resource.Layout.Main) — Georgios Tsaprazlis
– Georgios Tsaprazlis, Commented Nov 10, 2016 at 10:21

Justinfailber · Accepted Answer · 2016-11-10 10:26:23Z

2

You commented out the line:

SetContentView(Resource.Layout.Main);

This "binds" the current activity to the content view. If you dont bind that your program cant find any elements like your button. So it gives you a object reference error.

So remove the // infront of the SetContentView and it should work.

answered Nov 10, 2016 at 10:26

Justinfailber

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1 Comment

vibhav patil Over a year ago

Hi sorry Your solution worked and restart did it :) thanks a lot

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