处理 ImageList

Question

处理ImageList对象的适当方法是什么？

假设我有一个private ImageList imageList成员的类。现在，有时我会执行以下代码：

// Basically, lazy initialization.
if (imageList == null)
{
    imageList = new ImageList();
    Image[] images = Provider.CreateImages(...);
    foreach (var image in images)
    {
        // Does the 'ImageList' perform implicit copying here
        // or does it aggregate a reference?
        imageList.Images.Add(image); 

        // Do I need to do this?
        //image.Dispose();
    }
}

return imageList;

在同一个类中，我有Dispose方法实现，其执行方式如下：

public void Dispose()
{
    if (!disposed)
    {
        // Is this enough?
        if (imageList != null)
            imageList.Dispose();

        disposed = true;
    }
}

我确定此代码存在一些潜在问题，所以请您帮我改正。

Answer 1

是的，它会复制。请注意下面的 CreateBitMap 调用。因此，为了尽可能降低资源使用率，您应该取消对 dispose 行的注释。

 private int Add(ImageList.Original original, ImageList.ImageCollection.ImageInfo imageInfo)
  {
    if (original == null || original.image == null)
      throw new ArgumentNullException("value");
    int num = -1;
    if (original.image is Bitmap)
    {
      if (this.owner.originals != null)
        num = this.owner.originals.Add((object) original);
      if (this.owner.HandleCreated)
      {
        bool ownsBitmap = false;
        Bitmap bitmap = this.owner.CreateBitmap(original, out ownsBitmap);
        num = this.owner.AddToHandle(original, bitmap);
        if (ownsBitmap)
          bitmap.Dispose();
      }
    }
    else
    {
      if (!(original.image is Icon))
        throw new ArgumentException(System.Windows.Forms.SR.GetString("ImageListBitmap"));
      if (this.owner.originals != null)
        num = this.owner.originals.Add((object) original);
      if (this.owner.HandleCreated)
        num = this.owner.AddIconToHandle(original, (Icon) original.image);
    }
    if ((original.options & ImageList.OriginalOptions.ImageStrip) != ImageList.OriginalOptions.Default)
    {
      for (int index = 0; index < original.nImages; ++index)
        this.imageInfoCollection.Add((object) new ImageList.ImageCollection.ImageInfo());
    }
    else
    {
      if (imageInfo == null)
        imageInfo = new ImageList.ImageCollection.ImageInfo();
      this.imageInfoCollection.Add((object) imageInfo);
    }
    if (!this.owner.inAddRange)
      this.owner.OnChangeHandle(new EventArgs());
    return num;
  }

当 ImageList 处置时，它处置其所有图像的副本。因此，再次，是的，除了取消注释其他处理行之外，在表单关闭时处理它是正确的。

protected override void Dispose(bool disposing)
{
  if (disposing)
  {
    if (this.originals != null)
    {
      foreach (ImageList.Original original in (IEnumerable) this.originals)
      {
        if ((original.options & ImageList.OriginalOptions.OwnsImage) != ImageList.OriginalOptions.Default)
          ((IDisposable) original.image).Dispose();
      }
    }
    this.DestroyHandle();
  }
  base.Dispose(disposing);
}