ListBox.DragOver
Imports System.Drawing.Drawing2D
Imports System
Imports System.Drawing.Text
Imports System.Drawing
Imports System.Windows.Forms
Imports System.Math
Public Class MainClass
Shared Sub Main()
Dim form1 As Form = New Form1()
Application.Run(form1)
End Sub
End Class
Public Class Form1
Private m_DragSource As ListBox = Nothing
Private Sub Form1_Load(ByVal sender As System.Object, _
ByVal e As System.EventArgs) Handles MyBase.Load
lstUnselected.AllowDrop = True
lstSelected.AllowDrop = True
' Add event handlers.
AddHandler lstUnselected.MouseDown, AddressOf List_MouseDown
AddHandler lstUnselected.DragOver, AddressOf List_DragOver
AddHandler lstUnselected.DragDrop, AddressOf List_DragDrop
AddHandler lstUnselected.DragLeave, AddressOf List_DragLeave
AddHandler lstSelected.MouseDown, AddressOf List_MouseDown
AddHandler lstSelected.DragOver, AddressOf List_DragOver
AddHandler lstSelected.DragDrop, AddressOf List_DragDrop
AddHandler lstSelected.DragLeave, AddressOf List_DragLeave
End Sub
Private Sub List_MouseDown(ByVal sender As Object, _
ByVal e As System.Windows.Forms.MouseEventArgs)
Dim this_list As ListBox = DirectCast(sender, ListBox)
this_list.SelectedIndex = this_list.IndexFromPoint(e.X, e.Y)
If this_list.SelectedIndex < 0 Then Exit Sub
m_DragSource = this_list
this_list.DoDragDrop(this_list.SelectedItem.ToString,DragDropEffects.Move)
m_DragSource = Nothing
End Sub
Private Sub List_DragOver(ByVal sender As Object, ByVal e As System.Windows.Forms.DragEventArgs)
If m_DragSource Is Nothing Then Exit Sub
e.Effect = DragDropEffects.Move
Dim this_list As ListBox = DirectCast(sender, ListBox)
Dim pt As Point = this_list.PointToClient(New Point(e.X, e.Y))
Dim drop_index As Integer = this_list.IndexFromPoint(pt.X, pt.Y)
this_list.SelectedIndex = drop_index
End Sub
Private Sub List_DragLeave(ByVal sender As Object, ByVal e As System.EventArgs)
Dim this_list As ListBox = DirectCast(sender, ListBox)
this_list.SelectedIndex = -1
End Sub
' Accept the drop.
Private Sub List_DragDrop(ByVal sender As Object, _
ByVal e As System.Windows.Forms.DragEventArgs)
Dim this_list As ListBox = DirectCast(sender, ListBox)
MoveItem(e.Data.GetData(DataFormats.Text).ToString, _
m_DragSource, this_list, e.X, e.Y)
End Sub
' Move the value txt from drag_source to drop_target.
Private Sub MoveItem(ByVal txt As String, ByVal drag_source As ListBox, _
ByVal drop_target As ListBox, ByVal X As Integer, ByVal Y As Integer)
Dim drop_index As Integer = drop_target.SelectedIndex
If drop_index < 0 Then
drop_index = drop_target.Items.Add(txt)
Else
drop_target.Items.Insert(drop_target.SelectedIndex, txt)
End If
drop_target.SelectedIndex = drop_index
If drag_source Is drop_target Then
Dim target_index As Integer = drag_source.FindStringExact(txt)
If target_index = drop_index Then _
target_index = drag_source.FindStringExact(txt, target_index)
drag_source.Items.RemoveAt(target_index)
Else
drag_source.Items.Remove(txt)
End If
End Sub
End Class
<Global.Microsoft.VisualBasic.CompilerServices.DesignerGenerated()> _
Partial Public Class Form1
Inherits System.Windows.Forms.Form
'Form overrides dispose to clean up the component list.
<System.Diagnostics.DebuggerNonUserCode()> _
Protected Overloads Overrides Sub Dispose(ByVal disposing As Boolean)
If disposing AndAlso components IsNot Nothing Then
components.Dispose()
End If
MyBase.Dispose(disposing)
End Sub
'Required by the Windows Form Designer
Private components As System.ComponentModel.IContainer
'NOTE: The following procedure is required by the Windows Form Designer
'It can be modified using the Windows Form Designer.
'Do not modify it using the code editor.
<System.Diagnostics.DebuggerStepThrough()> _
Private Sub InitializeComponent()
Me.Label2 = New System.Windows.Forms.Label
Me.Label1 = New System.Windows.Forms.Label
Me.lstSelected = New System.Windows.Forms.ListBox
Me.lstUnselected = New System.Windows.Forms.ListBox
Me.SuspendLayout()
'
'Label2
'
Me.Label2.Location = New System.Drawing.Point(152, 0)
Me.Label2.Name = "Label2"
Me.Label2.Size = New System.Drawing.Size(144, 16)
Me.Label2.TabIndex = 11
Me.Label2.Text = "Right"
Me.Label2.TextAlign = System.Drawing.ContentAlignment.MiddleCenter
'
'Label1
'
Me.Label1.Location = New System.Drawing.Point(0, 0)
Me.Label1.Name = "Label1"
Me.Label1.Size = New System.Drawing.Size(144, 16)
Me.Label1.TabIndex = 10
Me.Label1.Text = "Left"
Me.Label1.TextAlign = System.Drawing.ContentAlignment.MiddleCenter
'
'lstSelected
'
Me.lstSelected.FormattingEnabled = True
Me.lstSelected.Items.AddRange(New Object() {"1", "2", "3", "4", "5", "6", "7", "8"})
Me.lstSelected.Location = New System.Drawing.Point(152, 16)
Me.lstSelected.Name = "lstSelected"
Me.lstSelected.Size = New System.Drawing.Size(144, 264)
Me.lstSelected.TabIndex = 9
'
'lstUnselected
'
Me.lstUnselected.FormattingEnabled = True
Me.lstUnselected.Items.AddRange(New Object() {"A", "B", "C", "D", "E", "F", "G", "H"})
Me.lstUnselected.Location = New System.Drawing.Point(0, 16)
Me.lstUnselected.Name = "lstUnselected"
Me.lstUnselected.Size = New System.Drawing.Size(144, 264)
Me.lstUnselected.TabIndex = 8
'
'Form1
'
Me.AutoScaleDimensions = New System.Drawing.SizeF(6.0!, 13.0!)
Me.AutoScaleMode = System.Windows.Forms.AutoScaleMode.Font
Me.ClientSize = New System.Drawing.Size(297, 281)
Me.Controls.Add(Me.Label2)
Me.Controls.Add(Me.Label1)
Me.Controls.Add(Me.lstSelected)
Me.Controls.Add(Me.lstUnselected)
Me.Name = "Form1"
Me.Text = "DragBetweenListBoxes"
Me.ResumeLayout(False)
End Sub
Friend WithEvents Label2 As System.Windows.Forms.Label
Friend WithEvents Label1 As System.Windows.Forms.Label
Friend WithEvents lstSelected As System.Windows.Forms.ListBox
Friend WithEvents lstUnselected As System.Windows.Forms.ListBox
End Class
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