C＃从我的自定义应用程序拖放到记事本

Question

I have a custom app which needs to support Drag and Drop. On Dragging the grid in my app, in its DoDragDrop method I have provided the object to be dropped in a serialized format.

When the drop is to one of my apps, it is able to deserailize the string and create the object.

What I want to do is allow the source app to be able to drop into NotePad/TextPad as well. I can see that I can drag and drop files from windows explorer to Notepad , but am not able to drag and drop plain text to NotePad. Guess it checks the DataFormat in the DragEnter event and dis-allows strings but allows files to be dropped into it.

• Is there a way to change yr format in the source app so that it provides a temp file / a string.
• Is it possible to provide the data in 2 formats so that the target drop can accept whichever format it is happy with?

thanks in advance!

Answer 1

You can add multiple formats of your data to the DataObject you pass into the DoDragDrop call, so just add another call to SetData to add the new formats. This is the most appropriate implementation, this way the Drop target can query for available formats and choose the one it likes best.

 DataObject d = new DataObject();
 d.SetData(DataFormats.Serializable, myObject);
 d.SetData(DataFormats.Text, myObject.ToString());
 myForm.DoDragDrop(d, DragDropEffects.Copy);

Answer 2

See here :

Storing Data in Multiple Formats

For this particular code snippet:

DataObject dataObject = new DataObject();
string sourceData = "Some string data to store...";

// Encode the source string into Unicode byte arrays.
byte[] unicodeText = Encoding.Unicode.GetBytes(sourceData); // UTF-16
byte[] utf8Text = Encoding.UTF8.GetBytes(sourceData);
byte[] utf32Text = Encoding.UTF32.GetBytes(sourceData);

// The DataFormats class does not provide data format fields for denoting
// UTF-32 and UTF-8, which are seldom used in practice; the following strings 
// will be used to identify these "custom" data formats.
string utf32DataFormat = "UTF-32";
string utf8DataFormat  = "UTF-8";

// Store the text in the data object, letting the data object choose
// the data format (which will be DataFormats.Text in this case).
dataObject.SetData(sourceData);
// Store the Unicode text in the data object.  Text data can be automatically
// converted to Unicode (UTF-16 / UCS-2) format on extraction from the data object; 
// Therefore, explicitly converting the source text to Unicode is generally unnecessary, and
// is done here as an exercise only.
dataObject.SetData(DataFormats.UnicodeText, unicodeText);
// Store the UTF-8 text in the data object...
dataObject.SetData(utf8DataFormat, utf8Text);
// Store the UTF-32 text in the data object...
dataObject.SetData(utf32DataFormat, utf32Text);