Develop Reference

Get and Select the ListBoxItem clicked from ListBox_PreviewMouseLeftButtonUp event

I have a ListBox that slides its ScrollViewer horizontally by dragging with the left mouse button pressed.
private ScrollViewer scrollViewer;
private Point scrollMousePoint = new Point();
private double horizontalOffset = 1;
private void MainWindow_Loaded(object sender, RoutedEventArgs e)
{
Border border = (Border)VisualTreeHelper.GetChild(myListBox, 0);
scrollViewer = (ScrollViewer)VisualTreeHelper.GetChild(border, 0);
// This works
}
private void myListBox_PreviewMouseLeftButtonDown(object sender, MouseButtonEventArgs e)
{
scrollMousePoint = e.GetPosition(scrollViewer);
horizontalOffset = scrollViewer.HorizontalOffset;
scrollViewer.CaptureMouse();
// This works
}
private void myListBox_PreviewMouseMove(object sender, MouseEventArgs e)
{
if (scrollViewer.IsMouseCaptured)
scrollViewer.ScrollToHorizontalOffset(horizontalOffset + (scrollMousePoint.X - e.GetPosition(scrollViewer).X));
// This works
}
private void myListBox_PreviewMouseLeftButtonUp(object sender, MouseButtonEventArgs e)
{
scrollViewer.ReleaseMouseCapture();
if (scrollMousePoint == Mouse.GetPosition(scrollViewer))
{
// Click
// Here I want to get and select the ListBoxItem that was pressed.
}
}
I want to get and select the ListBoxItem that was clicked.
To determine if it is a click without movement, I compare if the position saved in the PreviewMouseLeftButtonDown and in PreviewMouseLeftButtonUp events are the same.

Here you go:
private void myListBox_PreviewMouseLeftButtonUp(object sender, MouseButtonEventArgs e)
{
scrollViewer.ReleaseMouseCapture();
if (scrollMousePoint == Mouse.GetPosition(scrollViewer))
{
ListBox listBox = sender as ListBox;
if (listBox != null)
{
var element = VisualTreeHelper.HitTest(listBox, scrollMousePoint).VisualHit;
if (element.GetType() != typeof(ScrollViewer))
{
while (element.GetType() != typeof(ListBoxItem))
element = VisualTreeHelper.GetParent(element);
(element as ListBoxItem).IsSelected = true;
}
}
}
}

Drag and Drop Object onto Canvas with coordinates

I managed to drag and drop items from my ListView onto a canvas and show an image on it. I used this question as a template:
https://social.msdn.microsoft.com/Forums/en-US/cef5c42c-87a0-4e19-afc8-935284607488/drag-and-drop-controls-issue-from-listbox-into-canvas-wpf?forum=wpf
I also added the suggestion in that thread, so that the Item gets rendered where I drop it. These are the code behinds for my "Drawing Plate" (The canvas) and the ListView:
Canvas:
public partial class DrawingPlateUC : UserControl
{
IMessenger messenger = Messenger.Instance;
public DrawingPlateUC()
{
InitializeComponent();
}
void Canvas_Drop(object sender, DragEventArgs e)
{
if (e.Data.GetDataPresent("MyFormat"))
{
var module = e.Data.GetData("MyFormat") as Module;
Canvas CanvasView = sender as Canvas;
Image image = new Image();
image.Source = module.ModuleImage;
CanvasView.Children.Add(image);
}
}
private void Canvas_DragOver(object sender, DragEventArgs e)
{
// write down this point to a private member
Point enterPoint = e.GetPosition(this.moduleCanvas);
messenger.Send<Point>(enterPoint, MessengerTopics.MousePoint);
}
void Canvas_DragEnter(object sender, DragEventArgs e)
{
if (!(e.Data.GetDataPresent("contact")) || (sender == e.Source))
{
e.Effects = DragDropEffects.Copy;
}
}
}
ListView:
public partial class ItemListViewUC : UserControl
{
IMessenger messenger = Messenger.Instance;
Point startPoint;
Point enterPoint;
public ItemListViewUC()
{
messenger.Register<Point>(this, MessengerTopics.MousePoint, GetEnterPoint);
InitializeComponent();
}
private void GetEnterPoint(Point point)
{
enterPoint = point;
}
void StackPanel_PreviewMouseLeftButtonDown(object sender, MouseButtonEventArgs e)
{
startPoint = e.GetPosition(null);
}
void StackPanel_PreviewMouseMove(object sender, MouseEventArgs e)
{
Point mousPos = e.GetPosition(null);
Vector diff = startPoint - mousPos;
if ((e.LeftButton == MouseButtonState.Pressed) && (Math.Abs(diff.X) > SystemParameters.MinimumHorizontalDragDistance) && (Math.Abs(diff.Y) > SystemParameters.MinimumVerticalDragDistance))
{
ListView listView = sender as ListView;
ListViewItem listViewItem = FindAnchestor<ListViewItem>((DependencyObject)e.OriginalSource);
if (listViewItem == null) { return; }
var contact = (Module)listView.ItemContainerGenerator.ItemFromContainer(listViewItem);
DataObject dataObject = new DataObject("MyFormat", contact);
try
{
DragDrop.DoDragDrop(listViewItem, dataObject, DragDropEffects.Copy);
}
catch { }
// Set the Margin property to place the drag item on the canvas.
listViewItem.Margin = new Thickness(enterPoint.X, enterPoint.Y, 0, 0);
}
}
static T FindAnchestor<T>(DependencyObject current) where T : DependencyObject
{
do
{
if (current is T)
{
return (T)current;
}
current = VisualTreeHelper.GetParent(current);
}
while (current != null);
return null;
}
}
This here is supposed to draw the Image on the spot where I dropped it:
listViewItem.Margin = new Thickness(enterPoint.X, enterPoint.Y, 0, 0);
But it only renders on the top left corner, coordinates 0, 0 of the canvas. This is for all Items I drop, they overlay on that position. I already checked the coordinates, they are not 0, 0, but the ones where my mouse is when I drop the item.
This is my Window:

when you drop an item, you don't set any coordinate for Image:
void Canvas_Drop(object sender, DragEventArgs e)
{
if (e.Data.GetDataPresent("MyFormat"))
{
var module = e.Data.GetData("MyFormat") as Module;
Canvas CanvasView = sender as Canvas;
Image image = new Image();
image.Source = module.ModuleImage;
image.SetValue(Canvas.LeftProperty, _enterPoint.X);
image.SetValue(Canvas.TopProperty, _enterPoint.Y);
CanvasView.Children.Add(image);
}
}
private Point _enterPoint;
private void Canvas_DragOver(object sender, DragEventArgs e)
{
_enterPoint = e.GetPosition(this.moduleCanvas);
messenger.Send<Point>(_enterPoint, MessengerTopics.MousePoint);
}

I'm trying to drag and element using the mouse but it always starts dragging from a specific location and not the current location

I'm trying to drag a rectangle element called "Rec" using the mouse. I can drag it to the location I want and the rectangle stays there, but when I try to drag it again it returns to the first location and the dragging starts from there. I want to drag it from where I left it the last time. I just don't get where the problem is.
I have one Canvas only and all my elements are inside it, the Canvas is called the "maincanvas". I use the following very simple events to for dragging.
Point originalPosition = new Point(0, 0);
private void Rec_MouseMove(object sender, System.Windows.Input.MouseEventArgs e)
{
Point CurrPosition = Mouse.GetPosition(MainCanvas);
Canvas.SetLeft(e.Source as UIElement, -( originalPosition.X - CurrPosition.X));
Canvas.SetTop(e.Source as UIElement, -(originalPosition.Y - CurrPosition.Y));
}
private void Rec_MouseLeftButtonDown(object sender, MouseButtonEventArgs e)
{
UIElement a = e.Source as UIElement;
a.CaptureMouse();
Rec.MouseMove += Rec_MouseMove;
originalPosition = Mouse.GetPosition(MainCanvas);
}
private void Rec_MouseLeftButtonUp(object sender, MouseButtonEventArgs e)
{
Rec.MouseMove -= Rec_MouseMove;
UIElement a = e.Source as UIElement;
a.ReleaseMouseCapture();
originalPosition = new Point(0, 0);
}
I hope you guys could help me.

You should handle the mouse events on the Canvas like this:
<Canvas MouseLeftButtonDown="CanvasMouseLeftButtonDown"
MouseLeftButtonUp="CanvasMouseLeftButtonUp"
MouseMove="CanvasMouseMove">
...
</Canvas>
In the mouse down handler you would get the element that should be dragged by the MouseButtonEventArgs's OriginalSource property:
private UIElement draggedElement;
private Point lastMousePos;
private void CanvasMouseLeftButtonDown(object sender, MouseButtonEventArgs e)
{
if (e.OriginalSource != sender)
{
IInputElement canvas = (IInputElement)sender;
canvas.CaptureMouse();
draggedElement = e.OriginalSource as UIElement;
lastMousePos = e.GetPosition(canvas);
}
}
private void CanvasMouseLeftButtonUp(object sender, MouseButtonEventArgs e)
{
((IInputElement)sender).ReleaseMouseCapture();
draggedElement = null;
}
private void CanvasMouseMove(object sender, MouseEventArgs e)
{
if (draggedElement != null)
{
var p = e.GetPosition((IInputElement)sender);
var dx = p.X - lastMousePos.X;
var dy = p.Y - lastMousePos.Y;
lastMousePos = p;
Canvas.SetLeft(draggedElement, Canvas.GetLeft(draggedElement) + dx);
Canvas.SetTop(draggedElement, Canvas.GetTop(draggedElement) + dy);
}
}

Unable to drag and drop text from DataGridView to TextBox C#

I have been using code that others online have supplied but for some reason it won't let me drag items from the datagridview to the textbox. I highlight a row in the dataGridView and try to drag it to the textbox but nothing happens. I have also enabled the drop property for the textBox but still no difference. Here's the code that I am using:
private void dataGridView1_CellMouseDown(object sender, DataGridViewCellMouseEventArgs e)
{
if (e.Button == MouseButtons.Left)
{
DataGridView.HitTestInfo info = dataGridView1.HitTest(e.X, e.Y);
if (info.RowIndex >= 0)
{
if (info.RowIndex >= 0 && info.ColumnIndex >= 0)
{
string text = (String)
dataGridView1.Rows[info.RowIndex].Cells[info.ColumnIndex].Value;
if (text != null)
dataGridView1.DoDragDrop(text, DragDropEffects.Copy);
}
}
}
}
private void textBox1_DragDrop(object sender, DragEventArgs e)
{
if (e.Data.GetDataPresent(typeof(System.String)))
{
textBox1.Text = (System.String)e.Data.GetData(typeof(System.String));
}
}
private void textBox1_DragEnter(object sender, DragEventArgs e)
{
e.Effect = DragDropEffects.Copy;
}

Here is a small sample that i have done to give you an idea on how to do this... works perfectly for me. I used WinForms here. If WPF, there may be some more events you will need to register to in order for the drag+drop to register...
Note that you will want to add more code here and there to perform what you really want to do when you drag an item from one control to the other.
public partial class Form1 : Form
{
private Rectangle dragBoxFromMouseDown;
private int rowIndexFromMouseDown;
private int rowIndexOfItemUnderMouseToDrop;
private DataGridViewRow draggedrow;
public Form1()
{
InitializeComponent();
}
private void Form1_Load(object sender, EventArgs e)
{
List<StringValue> Items = new List<StringValue>() { new StringValue("1"), new StringValue("2"), new StringValue("3"), new StringValue("4"), new StringValue("5"), new StringValue("6") };
this.dataGridView1.DataSource = Items;
}
private void dataGridView1_MouseMove(object sender, MouseEventArgs e)
{
if ((e.Button & MouseButtons.Left) == MouseButtons.Left)
{
// If the mouse moves outside the rectangle, start the drag.
if (dragBoxFromMouseDown != Rectangle.Empty &&
!dragBoxFromMouseDown.Contains(e.X, e.Y))
{
// Proceed with the drag and drop, passing in the list item.
DragDropEffects dropEffect = dataGridView1.DoDragDrop(
dataGridView1.Rows[rowIndexFromMouseDown],
DragDropEffects.Move);
}
}
}
private void dataGridView1_MouseDown(object sender, MouseEventArgs e)
{
// Get the index of the item the mouse is below.
rowIndexFromMouseDown = dataGridView1.HitTest(e.X, e.Y).RowIndex;
if (rowIndexFromMouseDown != -1)
{
// Remember the point where the mouse down occurred.
// The DragSize indicates the size that the mouse can move
// before a drag event should be started.
Size dragSize = SystemInformation.DragSize;
// Create a rectangle using the DragSize, with the mouse position being
// at the center of the rectangle.
dragBoxFromMouseDown = new Rectangle(new Point(e.X - (dragSize.Width / 2),
e.Y - (dragSize.Height / 2)),
dragSize);
this.draggedrow = this.dataGridView1.CurrentRow;
}
else
// Reset the rectangle if the mouse is not over an item in the ListBox.
dragBoxFromMouseDown = Rectangle.Empty;
}
private void dataGridView1_DragOver(object sender, DragEventArgs e)
{
e.Effect = DragDropEffects.Move;
}
private void textBox1_DragEnter(object sender, DragEventArgs e)
{
e.Effect = DragDropEffects.Move;
}
private void textBox1_DragDrop(object sender, DragEventArgs e)
{
this.textBox1.Text = (string)this.draggedrow.Cells["Value"].Value;
}
}
public class StringValue
{
public StringValue(string s)
{
_value = s;
}
public string Value { get { return _value; } set { _value = value; } }
string _value;
}

can't you use DataGridViewCellMouseEventArgs e instead of hittest for getting row index in dataGridView1_CellMouseDown. below is your code modified hope this helps
private void dataGridView1_CellMouseDown(object sender, DataGridViewCellMouseEventArgs e)
{
if (e.Button == MouseButtons.Left)
{
if (e.RowIndex >= 0)
{
if (e.RowIndex >= 0 && e.ColumnIndex >= 0)
{
string text = (String)
dataGridView1.Rows[e.RowIndex].Cells[e.ColumnIndex].Value;
if (text != null)
dataGridView1.DoDragDrop(text, DragDropEffects.Copy);
}
}
}
}
private void textBox1_DragDrop(object sender, DragEventArgs e)
{
if (e.Data.GetDataPresent(typeof(System.String)))
{
textBox1.Text = (System.String)e.Data.GetData(typeof(System.String));
}
}
private void textBox1_DragEnter(object sender, DragEventArgs e)
{
e.Effect = DragDropEffects.Copy;
}

How to add textboxs to the dynamically created pictureboxes

I have a program which dynamically creates movable pictureboxes when I click on buttons. I need to do something like when I click on the picturebox, this click adds to my dynamically created picturebox a new textbox when I can write descripiton of this picturebox(name,...). This textbox should be able to move with picturebox.
using System;
using System.Collections.Generic;
using System.Drawing;
using System.Windows.Forms;
namespace WindowsFormsApplication1
{
public partial class Form1 : Form
{
List<PictureBox> pictureboxes = new List<PictureBox>();
public Form1()
{
InitializeComponent();
}
private void AddPictureBox(string imagePath)
{
var pb = new PictureBox();
pb.Name = "picturebox" + pictureboxes.Count;
pb.Location = new Point(pictureboxes.Count * 100, 100);
pb.Size = new Size(70, 70);
pb.BorderStyle = BorderStyle.None;
pb.SizeMode = PictureBoxSizeMode.StretchImage;
this.Controls.Add(pb);
pb.Image = Image.FromFile(imagePath);
pb.Refresh();
pb.MouseDown += new MouseEventHandler(picMouseDown);
pb.MouseMove += new MouseEventHandler(picMouseMove);
pb.MouseUp += new MouseEventHandler(picMouseUp);
pictureboxes.Add(pb);
Invalidate();
}
private void router_Click(object sender, EventArgs e)
{
AddPictureBox(#"D:\\router.jpg");
}
private void Form1_Load(object sender, EventArgs e)
{
}
int x = 0;
int y = 0;
bool drag = false;
private void picMouseDown(object sender, MouseEventArgs e)
{
// Get original position of cursor on mousedown
x = e.X;
y = e.Y;
drag = true;
}
private void picMouseMove(object sender, MouseEventArgs e)
{
if (drag)
{
PictureBox pb = (PictureBox)sender;
// Get new position of picture
pb.Top += e.Y - y;
pb.Left += e.X - x;
pb.BringToFront();
Invalidate();
}
}
private void picMouseUp(object sender, MouseEventArgs e)
{
drag = false;
}
private void switch1_Click(object sender, EventArgs e)
{
AddPictureBox(#"D:\HP ProBook 450\Desktop\Grafika\switch1.png");
}
private void panel1_Paint(object sender, PaintEventArgs e)
{
}
private void pc_Click(object sender, EventArgs e)
{
AddPictureBox(#"D:\HP ProBook 450\Desktop\pc.jpg");
}
private void server_Click(object sender, EventArgs e)
{
AddPictureBox(#"D:\HP ProBook 450\Desktop\server.png");
}
}
Thanks for any help :).

You can add a TextBox to a PictureBox in code like this:
TextBox newTextBox = new TextBox();
newTextBox.Parent = yourPictureBox;
// place it e.g. to the left bottom:
newTextBox.Location = new Point(10, yourPictureBox.Height - newTextBox.Height);
Note that this will add the TextBox to the Controls collection of the PB; so it will sit on top of the PictureBox; so, yes, it will move with the PictureBox but it will also hide a part or the PB!
If instead you simply want to group them, add them both to something like a Panel, again by setting that as their Parent!
Also note that you can't do this in the Designer; PictureBox is not really meant to act as a Container..
It doesn't matter how the PictureBox was created, as long as you have a reference to it.