Implement lazy drag & drop
I am trying to implement a lazy drag and drop operation. I want to show a listview with files to my user, when the user drags a file and drops it into a folder the content should be downloaded and 开发者_开发技巧delivered.
I am using the IDataObject interface, but my problem is that the GetData() method is queried way too early. For instance a drag over the desktop (without any drop involved) will query the GetData() method a couple of times. And each of these calls starts the download of the file :/
Now, my question is: What's wrong here - why is the GetData() method called without any drop? Is there another way to implement lazy drag & drop operations in .net?
Maybe this could work for you...
On every occurrence of the GetData() do this:
- you'll need some kind of a timer here.
- if your timer is already active, kill it.
- create and start a new timer. Make it 1sec or determine its duration from the experiment.
- on timer event do what has to be done.
I use similar procedure on many occasions where such workaround is needed.
I think GetData is being called so that the (potential) drop target can determine whether or not it can accept the (potential) drop item(s). Have you considered using a shell extension?
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