问题
After some searching i figured out how dragdrop is implemented for a picturebox. But there is one thing - the (inherited of course) allowdrop property isn't accessible from code or property window of picturebox class. So to make it work i added following line to my form-load:
((Control)pictureBox1).AllowDrop = true;
Why do i have to do that? In msdn it says: "This API supports the .NET Framework infrastructure and is not intended to be used directly from your code."
Any explanation appreciated and sorry for my grammar ;)
回答1:
The PictureBox class overrides the property and adds
[Browsable(false), EditorBrowsable(EditorBrowsableState.Never)]
This prevents it from being shown in IntelliSense.
However, you can still set the property without casting.
Microsoft does this when a property doesn't apply to a control. (eg, PictureBox.Text)
I don't know why AllowDrop wouldn't apply to a PictureBox; the source doesn't mention anything.
来源：https://stackoverflow.com/questions/4519728/dragdrop-support-of-picturebox-control