C＃字符串串联OutOfRange错误

Question

I'm utilizing Get String functions from a "Label" class to put together lines to print on a bitmap. The program compiles fine, and the previous form passes the LabelQueue properly (it would appear with no issue before I tried to print the bitmap). All the code of this particular initializer/constructor is below. The erroneous lines of code are the final three lines of the function before the "c++".

Let me know if you need me to add any more necessary code.

I'm getting an IndexOutofRange exception, claiming it was outside of the bounds of the array.

private LabelQueue lq;
    public Print(LabelQueue queue)
    {
        InitializeComponent();
        lq = queue;
        pictureBox1.Image = new Bitmap(2550, 3300);

        System.Drawing.Graphics formGraphics = this.CreateGraphics();
        System.Drawing.Font textFont = new System.Drawing.Font("Times New Roman", 8);
        System.Drawing.SolidBrush textBrush = new System.Drawing.SolidBrush(System.Drawing.Color.Black);
        System.Drawing.StringFormat textFormat = new System.Drawing.StringFormat();

        int x, y, c = 0;

        while (c < 30)
        {
            // Get coordinates for where to put values.
            x = ((c % 3) * 600) + 300;
            // Accounts for column gap
            if (c % 3 > 0)
                x = x + ((c % 3) - 1) * 75;
            y = ((c % 10) * 270) + 300;

            string firstLine, secondLine, thirdLine;

            firstLine = lq.labels[c].GetLastName() + ", " + lq.labels[c].GetFirstName() + " " + lq.labels[c].GetMiddleName();
            secondLine = lq.labels[c].GetNewStreet();
            thirdLine = lq.labels[c].GetNewCity() + ", " + lq.labels[c].GetNewState() + lq.labels[c].GetNewZIP() + lq.labels[c].GetNewCountry();

            formGraphics.DrawString(firstLine, textFont, textBrush, x, y, textFormat);  // Line turning up the error
            formGraphics.DrawString(firstLine, textFont, textBrush, x, y + 10, textFormat);  // Naturally, both these lines would need to be fixed too
            formGraphics.DrawString(firstLine, textFont, textBrush, x, y + 20, textFormat);

            c++;
        }

    }

Answer 1

Without a good, minimal , complete code example that reliably demonstrates the problem, it's impossible to know for sure the exact fix you need.

However, based on the information on this question and the comments so far, it appears that you simply aren't limiting your loop correctly. The while statement should look like this:

while (c < lq.Count())

Note that the above uses the Enumerable.Count() extension method. I chose that as the answer, because you didn't include the declaration/implementation of your LabelQueue object, so there's no way to know for sure what the correct syntax would be, but the extension method is likely to work because pretty much any reasonable collection type that supports an indexer will implement some interface that allows the Enumerable.Count() method to work well.

That said, your type probably has a Count property, which you can use instead of the Count() extension method. Either will work equally well.

Finally, for future reference it is fine to answer your own question. It's just that your answer should actually be an answer . Ie it needs to explain clearly what was wrong, and what you did to fix it. Writing "Issue is fixed" doesn't count as an answer.

For that matter, if you don't like my answer here and you want to write your own, you can still do that. You can even accept your own answer instead of mine if you'd rather. Just make sure it's a real answer.