如何防止FolderBrowserDialog崩溃？

Question

When the FolderBrowserDialog appears, and I press the close button or cancel button, it shows an error message. What do I need to do?

Thank you.

Here's my code.

private void openSlideShowFolder_Click(object sender, EventArgs e)
{
    folderBrowserDialog1.ShowDialog();
    string[] pics1 = Directory.GetFiles(folderBrowserDialog1.SelectedPath, "*.jpg");
    string[] pics2 = Directory.GetFiles(folderBrowserDialog1.SelectedPath, "*.jpeg");
    string[] pics3 = Directory.GetFiles(folderBrowserDialog1.SelectedPath, "*.bmp");
    folderFile = new string[pics1.Length + pics2.Length + pics3.Length];
    Array.Copy(pics1, 0, folderFile, 0, pics1.Length);
    Array.Copy(pics2, 0, folderFile, pics1.Length, pics2.Length);
    Array.Copy(pics3, 0, folderFile, pics1.Length + pics2.Length, pics3.Length);
    selected = 0;
    showImage(folderFile[selected]);
}

Answer 1

As was mentioned you need to catch whether the dialog returns OK. See if this helps:

private void openSlideShowFolder_Click(object sender, EventArgs e)
{
    if(folderBrowserDialog1.ShowDialog() == DialogResult.OK)
    {
    string[] pics1 = Directory.GetFiles(folderBrowserDialog1.SelectedPath, "*.jpg");
    string[] pics2 = Directory.GetFiles(folderBrowserDialog1.SelectedPath, "*.jpeg");
    string[] pics3 = Directory.GetFiles(folderBrowserDialog1.SelectedPath, "*.bmp");
    folderFile = new string[pics1.Length + pics2.Length + pics3.Length];
    Array.Copy(pics1, 0, folderFile, 0, pics1.Length);
    Array.Copy(pics2, 0, folderFile, pics1.Length, pics2.Length);
    Array.Copy(pics3, 0, folderFile, pics1.Length + pics2.Length, pics3.Length);
    selected = 0;
    showImage(folderFile[selected]);
    }
}

Answer 2

The documentation for ShowDialog shows that it gives a result, telling you whether the user clicked OK. Your code is assuming the user always clicks OK, it's continuing regardless of the result. You need to check the return value, and only continue if it's DialogResult.OK .

If you do continue even though the user clicked Cancel or Close, several assumptions that should otherwise always be valid, may not hold. In particular, there is no path that the user has selected, because the user has not selected anything.