While loop warns of always true since value of type 'int' is never equal to 'null' of type 'int'

Question

I'm new to C#, working through some examples in the C# Head First book and trying to apply what I've learned in a practical manner. I'm trying to read in a text file with the following code:

private StreamReader upload;

private void Form1_Load(object sender, EventArgs e)
{
    if (File.Exists(@"C:\Users\Recon 5\Desktop\ToDo.txt"))
    {
        upload = new StreamReader(@"C:\Users\Recon 5\Desktop\ToDo.txt");
        while (upload.Peek() != null)
        {
            currentTasks.Items.Add(upload.ReadLine());
        }
        upload.Close();
    }
}

The above code provides the intended result, i.e. adding items into a list box from a text file. What I don't understand is why the following expression:

upload.Peek() != null

is giving me the following compiler warning:

The result of the expression is always true since a value of type int is never equal to null of type int.

I've tried looking in the Windows library for a response, but understanding the API is a task in its own right.

I guess what I'm looking for is helpful pointers to either guide my search or resources to assist me in discovering the answer myself. I'm sure there might be a better way to write this task but given where I'm at with my understanding of the language I feel it important to use and understand the tools I have learned thus far, in this case the while loop.

Answer 1

while (upload.Peek() != null)

...looks suspicious since StreamReader.Peek() can't return null. I suspect the correct line would be;

while (upload.Peek() != -1)

Return Value
Type: System.Int32
An integer representing the next character to be read, or -1 if there are no characters to be read or if the stream does not support seeking.