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    <p>The code you have has several severe problems:</p> <ol> <li>The reason for your <code>NullReferenceException</code> is two-fold: <ol> <li>You declare an array of <code>GreyHound</code>, but you never initialize it. That means, that <code>dog</code> is <code>null</code> and trying to access <code>dog[1]</code> results in a NullReferenceException.</li> <li>If you would fix that, you would still have another problem:<br> Assuming that <code>GreyHound</code> is a reference type that means that you will have to create an instance for each item in the array. With your current code, all items in the array are <code>null</code> which leads to a <code>NullReferenceException</code> when trying to access the property <code>MyPictureBox</code> on any item in the array, because <code>dog[1]</code> would be <code>null</code>.</li> </ol></li> <li>For every item in the array, you first assign a new instance of a <code>PictureBox</code> to the property <code>MyPictureBox</code> but you overwrite that value in the very next line with <code>pictureBoxX</code>.</li> <li>As we are in C#, arrays are zero indexed, so the first item has the index 0 and not 1.</li> </ol> <p>Fix your code like so:</p> <pre><code>GreyHound[] dog = new GreyHound[4]; // solves problem 1.1 dog[0] = new GreyHound(); // solves problem 1.2 dog[0].MyPictureBox = pictureBox1; dog[1] = new GreyHound(); // solves problem 1.2 dog[1].MyPictureBox = pictureBox2; dog[2] = new GreyHound(); // solves problem 1.2 dog[2].MyPictureBox = pictureBox3; dog[3] = new GreyHound(); // solves problem 1.2 dog[3].MyPictureBox = pictureBox4; </code></pre>
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    1. USDaniel Hilgarth
    1. USDaniel Hilgarth
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    1. COThank you very much, the problem has been solved, and now I also understood where I wennt wrong. Thanks again for explaining it perfectly :)
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      1. USVarun Kumar
 

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