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POWhy does this code throw a NullReferenceException when adding strings to listbox from a text file?
 

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  1. POWhy does this code throw a NullReferenceException when adding strings to listbox from a text file?
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    <p>Here's the code:</p> <pre><code>public partial class Form1 : Form { //Initialize Array to hold student names new string[] names = { "David Palladini", "Michael Reyes", "Bram Lesser", "Hans Herrmann", "Nathan Texeira" }; //Initialize Array to hold student evaluations new double[,] evaluation = { {1.0, 0.8, 0.9 ,1.0,0.6}, {0.2, 0.9, 0.5, 0.6, 0.7}, {0.5, 1.0, 1.0, 1.5, 0.9}, {0.9, 0.9, 0.9, 1.0, 1.0}, {1.0, 0.9, 1.0, 0.8, 0.9} }; public Form1() { StreamWriter outputFile; outputFile = File.CreateText("names.txt"); foreach (string name in names) { outputFile.WriteLine(name); } outputFile.Close(); string studentName; StreamReader inputFile; inputFile = File.OpenText("names.txt"); while (!inputFile.EndOfStream) { //Reads name from text file studentName = inputFile.ReadLine(); //Writes name to listbox nameListBox.Items.Add(studentName); } inputFile.Close(); InitializeComponent(); } </code></pre> <p>The evaluation array is irrelevant for now. I'm trying to display all the names in the names array into a listbox immediately upon launch. I also know that writing them into a text file and then reading them from it is a very roundabout way of doing things, but in this situation I have to. </p> <p>The problem is that it throws a NullReferenceException error right here:</p> <pre><code> //Writes name to listbox nameListBox.Items.Add(studentName); </code></pre> <p>For the life of me I can't figure out why. Is the original array not being written into the text file correctly? Or am I doing something wrong when trying to read back the strings?</p>
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    1. UScjharty
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    1. COmake sure `nameListBox` exists and is initialized, and make sure `studentName` exists and has data in it.
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      1. POWhy does this code throw a NullReferenceException when adding strings to listbox from a text file?
      1. USMehdi Karamosly
 

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