使图片框具有多个图像，例如带有上一个/下一个按钮的画廊[c＃]

Question

到目前为止，我的代码有效，除了上一个和下一个按钮仅适用于2张图像。为什么？我不明白，列表应该包含所有内容，然后为什么呢？

如果我添加10张图片，我想一直按上一首和下一首。

    int PageNumber = 0;
    // A list of image filenames to display. You could populate this by 
    reading filenames from disk


    List<string> ImageFilenames = new List<string>();
    private void btnAdd_Click(object sender, EventArgs e)
    {

        // open file dialog   
        OpenFileDialog open = new OpenFileDialog();
        open.Multiselect = true;
        // image filters  
        open.Filter = "Image Files(*.jpg; *.jpeg; *.gif; *.bmp)|*.jpg; 
     *.jpeg; *.gif; *.bmp";
        if (open.ShowDialog() == DialogResult.OK)
        {
            pctBox.SizeMode = PictureBoxSizeMode.CenterImage;
            // display image in picture box  
            ImageFilenames.Add(open.FileName);
            pctBox.Image = new Bitmap(open.FileName);

            // image file path  
            //textBox1.Text = open.FileName;
        }
    }

    private void btnPrevious_Click(object sender, EventArgs e)
    {
        //if there is no more pages
        if (PageNumber == ImageFilenames.Count - 1)
        {
            // Move to the next page
            --PageNumber;

            // Load up the PictureBox with the new image.
            pctBox.Image = new Bitmap(ImageFilenames[PageNumber]);
        }

    }

    private void btnNext_Click(object sender, EventArgs e)
    {

        // If we're not yet on the last page...

        if (PageNumber < ImageFilenames.Count - 1)
        {
            // Move to the next page
            ++PageNumber;
            // Load up the PictureBox with the new image.
            pctBox.Image = new Bitmap(ImageFilenames[PageNumber]);
        }

    }

Answer 1

稍微改变了您的逻辑。请找到代码以供参考

 int nTotalNumber = 0;
 int nCurrentItem = 0;
 List<string> ImageFilenames = new List<string>();

 private void LoadImage()
 {
   using (OpenFileDialog open = new OpenFileDialog())
   {
      open.Multiselect = true;
      open.Filter = "Image Files(*.jpg; *.jpeg; *.gif; *.bmp;*.png)|*.jpg; *.jpeg; *.gif; *.bmp; *.png";
      if (open.ShowDialog() == DialogResult.OK)
      {
         string sFileName = open.FileName;
         ImageFilenames = open.FileNames.ToList();
      }
      pbBox.Image = Image.FromFile(ImageFilenames[0]);
    }
    if (ImageFilenames.Count > 0)
         nTotalNumber = ImageFilenames.Count; 
 }

 private void btnPrevious_Click(object sender, EventArgs e)
 {
     nCurrentItem--;

     if (nCurrentItem < 0)
        nCurrentItem = 0;

     else if (nCurrentItem < nTotalNumber)
         pbBox.Image = Image.FromFile(ImageFilenames[nCurrentItem]);
  }

  private void btnNext_Click(object sender, EventArgs e)
  {
      nCurrentItem++;

      if (nCurrentItem > nTotalNumber)
        nCurrentItem = nTotalNumber;

      else if (nCurrentItem < nTotalNumber)
          pbBox.Image = Image.FromFile(ImageFilenames[nCurrentItem]);
   }