DragDropSample1 (VB)
This sample demonstrates drag & drop within the tree control, dragging data to a textbox and dropping data on the tree control from File Explorer.
Imports System.Reflection
Imports Softelvdm.Controls
Imports Softelvdm.SftTreeNET
Public Class Form1
Private m_PlusImage As Image = Bitmap.FromFile("..\\..\\ExpandableNormal.bmp") ' a small + bitmap
Private m_MinusImage As Image = Bitmap.FromFile("..\\..\\CollapsableNormal.bmp") ' a small - bitmap
Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
' This sample demonstrates drag & drop using one textbox control.
' To prepare for this sample, create a new project with a blank form and add
' a SftTree/NET control named sftTree1.
' In addition, a textbox named textbox1 is needed. Try dragging data from the
' tree control to the text box.
' It is also possible to drag files from Windows Explorer to the tree control.
' No files are moved/copied, merely their names are added to the tree control.
sftTree1.Initializing = True
sftTree1.Columns.Count = 1
For i As Integer = 0 To 9
Dim item As ItemClass = sftTree1.ItemCollection.Add("Item " & i.ToString())
For ic As Integer = 0 To 9
Dim child As ItemClass
child = item.Add("Child item " & ic.ToString())
Next
Next
sftTree1.ItemCollection.Collapse(CollapseStyleEnum.All)
sftTree1.Columns.MakeOptimal(0, False)
sftTree1.RecalcHorizontalExtent()
' We need to set up the tree control as a drop target
sftTree1.AllowDrop = True
sftTree1.AutoExpandDragDrop = True
sftTree1.AutoExpandArea = AutoExpandAreaEnum.AllColumns
sftTree1.Initializing = False
' We also need to set up the text box so we can drop data
textBox1.AllowDrop = True
End Sub
Private Sub sftTree1_DragDetected(ByVal sender As Object, ByVal e As Softelvdm.SftTreeNET.DragDetectedEventArgs) Handles sftTree1.DragDetected
Debug.Print("We're starting to drag something")
DumpValues(e)
' based on what we are dragging, make up a string
Dim s As String = ""
s = e.Area.ToString() & " in "
s = s & e.Item.UsageLocation.ToString() & ": "
If Not e.Cell Is Nothing Then
If e.Cell.Text = "" Then
s = s & "(empty cell) "
Else
s = s & e.Cell.Text & " "
End If
ElseIf Not e.RowHeader Is Nothing Then
If e.RowHeader.Text = "" Then
s = s & "(empty row header) "
Else
s = s & e.RowHeader.Text & " "
End If
ElseIf Not e.Item Is Nothing Then
s = s & " an item "
End If
e.Handled = True
sftTree1.DoDragDrop(s, DragDropEffects.Copy)
End Sub
Private Sub textBox1_DragEnter(ByVal sender As Object, ByVal e As System.Windows.Forms.DragEventArgs) Handles textBox1.DragEnter
Debug.Write("*** textBox1 DragEnter ")
DumpValues(e)
If e.Data.GetDataPresent(DataFormats.UnicodeText) Then
e.Effect = DragDropEffects.Copy
End If
End Sub
Private Sub textBox1_DragDrop(ByVal sender As Object, ByVal e As System.Windows.Forms.DragEventArgs) Handles textBox1.DragDrop
Debug.Write("*** textBox1 DragDrop ")
DumpValues(e)
If e.Data.GetDataPresent(DataFormats.UnicodeText) Then
textBox1.Text = e.Data.GetData("System.String")
End If
End Sub
Private Sub sftTree1_DragEnter(ByVal sender As Object, ByVal e As System.Windows.Forms.DragEventArgs) Handles sftTree1.DragEnter
Debug.Write("*** sftTree1 DragEnter ")
DumpValues(e)
If e.Data.GetDataPresent(DataFormats.UnicodeText) Then
e.Effect = DragDropEffects.Copy
ElseIf e.Data.GetDataPresent(DataFormats.FileDrop) Then
e.Effect = DragDropEffects.Copy
Else
e.Effect = DragDropEffects.None
End If
End Sub
Private Sub sftTree1_DragOver(ByVal sender As Object, ByVal e As System.Windows.Forms.DragEventArgs) Handles sftTree1.DragOver
' in this example, if we don't have a valid drop target,
' we STILL allow drops
If sftTree1.DropTarget Is Nothing Then
e.Effect = DragDropEffects.Copy
End If
End Sub
Private Sub sftTree1_DragDrop(ByVal sender As Object, ByVal e As System.Windows.Forms.DragEventArgs) Handles sftTree1.DragDrop
Debug.Write("*** sftTree1 DragDrop ")
DumpValues(e)
Dim item As ItemClass = sftTree1.DropTarget
Dim s As String = ""
Dim a As Array = Nothing
If e.Data.GetDataPresent(DataFormats.UnicodeText) Then
s = e.Data.GetData("System.String")
ElseIf (e.Data.GetDataPresent(DataFormats.FileDrop)) Then
a = e.Data.GetData(DataFormats.FileDrop)
Else
Return
End If
Dim newItem As ItemClass = Nothing
sftTree1.Initializing = True
If s.Length > 0 Then
If Not item Is Nothing Then
newItem = item.Add(s)
item.Expand(ExpandStyleEnum.DirectOnly)
Else
newItem = sftTree1.ItemCollection.Add(s)
End If
Else
For Each o As Object In a
s = o
If Not item Is Nothing Then
newItem = item.Add(s)
item.Expand(ExpandStyleEnum.DirectOnly)
Else
newItem = sftTree1.ItemCollection.Add(s)
End If
Next
End If
sftTree1.Columns.MakeOptimal(0, False)
sftTree1.RecalcHorizontalExtent()
newItem.ScrollIntoView()
sftTree1.FocusObject = newItem
newItem.Selected = True
sftTree1.Initializing = False
End Sub
' This is a small helper routine to show all properties and fields of an object
Private Sub DumpValues(ByVal o As Object)
Dim api() As PropertyInfo = o.GetType().GetProperties()
For Each pi As PropertyInfo In api
Dim s As String
On Error Resume Next
pi.GetValue(o, New Object() )
Debug.Write(" " & pi.Name & " " & s)
Next
Dim afi() As FieldInfo = o.GetType().GetFields()
For Each fi As FieldInfo In afi
Dim t As Object = fi.GetValue(o)
Dim s As String = "(null)"
If Not t Is Nothing Then s = t.ToString()
Debug.Write(" " & fi.Name & " " & s)
Next
Debug.WriteLine("")
End Sub
End Class
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