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POPorting WinForms drag and drop to WPF drag and drop
 

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    <p>I am porting my program from WinForms to WPF and have ran into some issues with the drag and drop. It should allow for dragging from a TreeView (it is like a file explorer) to a textbox which opens the file. However, the WPF version acts like a copy-and-paste of the <code>TreeViewItem</code>'s header text automatically. I think I just have something mixed up? Possibly the <code>DataObject</code> stuff.</p> <p>The fully functional, relevant WinForms code:</p> <pre><code>private void treeView1_MouseMove(object sender, MouseEventArgs e) { if (e.Button != MouseButtons.Left) return; TreeNode node = treeView1.GetNodeAt(e.Location); if (node != null) treeView1.DoDragDrop(node, DragDropEffects.Move); } textbox[i].DragDrop += (o, ee) =&gt; { if (ee.Data.GetDataPresent(typeof(TreeNode))) { TreeNode node = (TreeNode)ee.Data.GetData(typeof(TreeNode)); ((Textbox)o).Text = File.ReadAllLines(pathRoot + node.Parent.FullPath); ... </code></pre> <p>The WPF code that should do the same thing:</p> <pre><code>private void TreeView_PreviewMouseLeftButtonDown(object sender, MouseButtonEventArgs e) { TreeViewItem item = e.Source as TreeViewItem; if (item != null) { DataObject dataObject = new DataObject(); dataObject.SetData(DataFormats.StringFormat, GetFullPath(item)); DragDrop.DoDragDrop(item, dataObject, DragDropEffects.Move); } } //textbox[i].PreviewDrop += textbox_Drop; private void textbox_Drop(object sender, DragEventArgs e) { TreeViewItem node = (TreeViewItem)e.Data.GetData(typeof(TreeViewItem)); //null? ((Textbox)sender).Text = ""; //this is being executed BUT then the node's header text is being pasted //also, how do I access the DataObject I passed? } </code></pre> <p><strong>Problem:</strong> In my WPF version, I am setting the textbox's text to empty (as a test), which occurs, but afterwards the TreeViewItem's header text is being pasted which is not what I want.</p> <p><strong>Questions:</strong> What is the correct way to port this WinForms code to WPF? Why is the text being pasted in the WPF version? How do I prevent that? Am I using the correct events? How do I access the <code>DataObject</code> in <code>textbox_Drop</code> so that I can open the file like I did in the WinForms version? Why is TreeViewItem node always null in the WPF version?</p>
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    1. USAustin Henley
    1. USAustin Henley
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    1. COThis appears relevant: http://msdn.microsoft.com/en-us/library/hh144798.aspx EDIT: The important bit here is that `TextBox` and all its kin have "default" implementations for DragDrop, and it's recommended you just bolt onto those rather than spinning your own.
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      1. USJerKimball
 

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