I want to drag and drop a control (label for example) in a winform application. I saw some examples on dragging and dropping text, but this is not what I want. I want to enable the user to move a control around. Can anyone direct me to some resources or examples? Thanks.
you should look at examples on how to make draggable controls.
There are some answers here in SO as well.
See this Move controls when Drag and drop on panel in C#
this is a complete example on how to host the Form Designer:
Tailor Your Application by Building a Custom Forms Designer with .NET
I did something similar in Delphi long time ago, will search the source code, convert it into .NET C# and make a wiki page on that matter, as it is becoming such popular question recently :)
As far as i understand, where you wish to drop a control is called a container, infact any control can act as a container. So first that container, you need to enable the drop property as well as the drag property of the controls which you need to drag.
Then write events (Candrag, candrop, controladded, etc.) for each control where in which, some logic to hold the objects and display them as you may want.
Say, ill take an example where in which, you wish to drag imagetext from combombox into a picturebox and then make the picturebox analyze the text and fine related file name in a directory and load that image into its if its present.
So here, when you start dragging the text from combombox, you have to write some logic in event candrag. Then once you drop, you have to write logic to understand what kinda object was added and get the text related to it (kinda deciphering) in the control where you drop other control.
Sorry, i have no code to give you now, but i hope you got the idea how its done. May be this article can help you? http://vicky4147.wordpress.com/2007/02/04/a-simple-drag-drop-in-winforms/
bool draging = false;
int curPosX, curPosY;
private void label2_MouseDown(object sender, MouseEventArgs e)
{
draging = true;
curPosX = Cursor.Position.X;
curPosY = Cursor.Position.Y;
}
private void label2_MouseMove(object sender, MouseEventArgs e)
{
if (draging)
{
label2.Left += Cursor.Position.X - curPosX;
curPosX = Cursor.Position.X;
label2.Top += Cursor.Position.Y - curPosY;
curPosY = Cursor.Position.Y;
}
}
private void label2_MouseUp(object sender, MouseEventArgs e)
{
draging = false;
}
Related
I've been attempting to drag an image from a Picturebox outside my form boundaries just in the same manners that Windows Explorer does, so for instance, dropping it into an external webbrowser to view, Skype to send etc
Switched to VB.NET to find the most basic solution, but no luck there unfortunately. The drag n' drop effect shows outside my form, however, no application accepts or properly responses to the image drop.
Code is ran on the MouseDown event of the Picturebox.
Me.DoDragDrop(PictureBox1.Image, DragDropEffects.All)
Any ideas? C# or VB.NET, both are fine for me.
Thanks
I found this solution for WPF: Drag and drop to Desktop / Explorer
For winforms works like this:
private void DragDropImage()
{
var filename = "filename.jpg";
var path = Path.Combine(Path.GetTempPath(), filename);
this.pictureBox1.Image.Save(path);
var paths = new[] { path };
this.pictureBox1.DoDragDrop(new DataObject(DataFormats.FileDrop, paths), DragDropEffects.Copy);
}
private void pictureBox1_MouseMove(object sender, MouseEventArgs e)
{
if (e.Button == MouseButtons.Left)
this.DragDropImage();
}
This will copy the content of your picturebox to a temp directory. Then makes a dodragdrop. Its tested and works for me. Code is executed in MouseMove and checks if mouse is clicked.
feal's code worked, however, I didn't see the need to waste time/processing power on saving the image so I modified it to the following in case somebody faces the same issue in the future. Code is inserted in the MouseDown event of the control.
VB.NET:
Me.DoDragDrop(New DataObject(DataFormats.FileDrop, {"Image Path"}), DragDropEffects.All)
C#:
this.DoDragDrop(new DataObject(DataFormats.FileDrop, new[] {#"Image Path"}), DragDropEffects.All);
Thanks a lot, feal.
I am attempting a drag and drop in WPF.
My program allows you to drag coloured labels around the screen, in essence giving you the effect that squares are being dragged and dropped.
Bearing in mind that only the text is dragged rather then the control itself (i.e. not the colour):
What I would like to achieve is that when the drop event fires, I can change the colour of the label which I dragged the text from.
After consulting MSDN I've failed to figure out how to get at the control in question and after plenty of trial and error I'm hoping somebody here can help. https://msdn.microsoft.com/en-us/library/system.windows.forms.drageventargs.data(v=vs.110).aspx
Below is a sample of code which works, but the label who's colour I want to change is hard-coded, whereas in reality it could be any one of a number of labels.
private void ObjDrop(object sender, DragEventArgs e)
{
//testSquare is a hardcoded label
testSquare.Background = Brushes.LimeGreen;
//what I really need is for a variable to detect which label to access each time before I change its colour. So something along the lines of
Label myLabel = someCodeToGetTheLabelThatWasDragged;
myLabel.Background = Brushes.LimeGreen;
}
Hopefully I explained things well enough, thanks in advance.
You would use the IDataObject.GetData(Type) method to extract the the object in DragEventArgs.Data property. From there, you should be able to access whatever you store in the IDataObject.
This is a pretty general answer. To achieve said answer, that means you'll have to write your own class that implements IDataObject which contains the original control/control's name etc., then set the IDataObject when drag in initialized.
There may be an alternate solution available. I would watch what e.Data is in your current example, and try to work with that. If e.Data is of type Label, through casting, you could access the label that way, e.g. (e.Data as Label).Background = Brushes.LimeGreen;.
In a Drag and Drop implementation I've seen, the IDataObject contains the DropTarget and the DragSource, that way you can compare the two and allow/disallow things/types from being dragged and dropped by setting the Effect.
This page provides the solution for what i'm looking to do.
WPF Drag and Drop - Get original source info from DragEventArgs
The following code in particular used in the drop event method allowed me to achieve my aim
Label lbl = e.Data.GetData("System.Windows.Controls.Label") as Label;
After that I could manipulate the source of the drag whatever way I wished.
I'm new into WPF and have a problem I can't seem to find a solution for.
I'm writing a G19 (Keyboard) applet. This Keyboard has a 320x240 display attached, which you can access with C#.
I'm using WPF for this, because I don't need to do any GDI drawing anymore and use the normal controls instead.
So. It works as I wish. Everything draws properly except one UserControl. I have downloaded this control -> http://marqueedriproll.codeplex.com/
In the designer, the control works, the Loaded event get's fired and the animation is good.
When I run my application, I just see the label and the text. The animation does not work, and the Loaded event does not fire anymore.
Any help is appreciated.
The main function is my wrapper. The wrapper is already a Usercontrol and displays plugins which are switchable. This wrapper has the Frame Control(Wrapper1). I replace the content of this frame every time I switch the plugin.
public void SetPlugin(IPlugin plugin)
{
if (this.MainPlugin != null)
{
this.MainPlugin.OnHide();
((UserControl)this.MainPlugin).Visibility = System.Windows.Visibility.Hidden;
}
this.MainPlugin = plugin;
((UserControl)this.MainPlugin).Visibility = System.Windows.Visibility.Visible;
this.MainPlugin.OnShow();
this.Wrapper1.Content = this.MainPlugin;
}
I think it's the right approach to handle a plugin system that way. The plugin get's drawed on my keyboard.
What I don't understand is why the usercontrol only works in the designer view and not in the running application.
The basic code of the scrolling label is so:
public MarqueeText()
{
this.Loaded += new RoutedEventHandler(MarqueeText_Loaded);
InitializeComponent();
canMain.Height = this.Height;
canMain.Width = this.Width;
}
void MarqueeText_Loaded(object sender, RoutedEventArgs e)
{
StartMarqueeing(_marqueeType);
}
I don't see a reason why it doesn't work. Actually Ive always found a way to fix a problem but this time I see nothing.
Thanks in advance. Your help is really required today.
Have a great saturday! :)
I am guessing you are rendering to a bitmap target, rather than onscreen. If you are using RenderTargetBitmap, you have a couple of responsibilities. You need to set both a presentation source, and make sure you run events on the dispatcher.
Normally, App.xaml or Application.Run does this for you, but if you are not using a Window, you are on your own.
See this related question for details.
Ok, I have the following problem:
I would like to scroll an overflowing ListBox up and down.
I would like to do it programatically in a custom control inheriting from ListBox. I've seen and tested things such as scrollIntoView. However I would like to have a scrolling similar to what you can have when using the mouse's wheel.
I don't want to have the mouse involved at all (I'm developing for the Kinect, and since there are 2 cursors, I don't want to use the Mouse event args)
a google search didn't turn up much: I've read plenty of thread on how to scroll in code behind using scrollIntoView, or putting a scrollbar and such.
I think this will involve two steps:
Find the scrollViewer control inside listBox template
Perform the actual scrolling in that scrollViewer
For the first step implementation please take a look here. Here is the code snippet extracted from there:
this.Loaded += MainWindow_Loaded;
void MainWindow_Loaded(object sender, RoutedEventArgs e)
{
var scrollViewer = listbox.Template.FindName("Scroller", listbox);
}
And for the second step you should use one of the methods from here, LineDown or PageDown probably.
P.S.: I haven't tested this approach at all since I do not have VS installed so feel free to add the needed code here.
OK, first for context look at the Windows desktop; You can take items (folders, files) on the desktop and drag them around to different places and they "stay" where you dragged them. This seems to be a pretty useful feature to offer users so as to allow them to create their own "groupings" of items.
My question is thus:
Is there a control in .NET that approximates this behavior with a collection of items?
I'm thinking something like a listview in "LargeIcon" mode, but it allows you to drag the icons around to different places inside the control.
You can do this with a standard ListView control by implementing drag-and-drop. Here's a sample control that does this:
using System;
using System.Drawing;
using System.Windows.Forms;
public class MyListView : ListView {
private Point mItemStartPos;
private Point mMouseStartPos;
public MyListView() {
this.AllowDrop = true;
this.View = View.LargeIcon;
this.AutoArrange = false;
this.DoubleBuffered = true;
}
protected override void OnDragEnter(DragEventArgs e) {
if (e.Data.GetData(typeof(ListViewItem)) != null) e.Effect = DragDropEffects.Move;
}
protected override void OnItemDrag(ItemDragEventArgs e) {
// Start dragging
ListViewItem item = e.Item as ListViewItem;
mItemStartPos = item.Position;
mMouseStartPos = Control.MousePosition;
this.DoDragDrop(item, DragDropEffects.Move);
}
protected override void OnDragOver(DragEventArgs e) {
// Move icon
ListViewItem item = e.Data.GetData(typeof(ListViewItem)) as ListViewItem;
if (item != null) {
Point mousePos = Control.MousePosition;
item.Position = new Point(mItemStartPos.X + mousePos.X - mMouseStartPos.X,
mItemStartPos.Y + mousePos.Y - mMouseStartPos.Y);
}
}
}
I think the closest would the ListView control, but even that is more like an explorer window. You might be able to create your own view that does what you want, but you'd need to manually persist icon locations somewhere.
If you are not opposed to using WPF, Josh Smith has created a pretty neat canvas that I am currently using for a project. It allows you to add controls and drag them around the canvas. You would have to handle what is loaded on the canvas and where on the next load of the program, but that is pretty simple.
http://www.codeproject.com/KB/WPF/DraggingElementsInCanvas.aspx
This depends on whether this is a windows application or a web browser based application. In either case you need to have some sort of container to manage the locations of controls. You can manage the position of controls inside of a container with their X and Y coordinates.
You would handle the actual movement using the drag events. So you have drag start, while dragging (you might show a place holder graphic or change the cursor), and finally a drag end (set the control's x and y to the new position). Obviously these aren't the actual event names, but a search for "how to handle drag events" should get you started.
In a web environment, I know jquery has dragging capability built in. So you might want to look at that. The one big thing you'll have to be careful of is maintaining the positions of your controls between postbacks. I'm not sure what would happen in this case.
Windows uses ListView32, an internal control with drag n' drop placeholder features, custom borders...
The icon location can be stored in a XML file, or in the application settings (by putting the XML as string and converting it to file when needed).
You can do, for example:
<icons>
<icon1>
<name>Icon1</name>
<text>My PC</text>
<imageIndex>16</imageIndex>
</icon1>
<icon2>
.....
</icon2>
.....
</icons>
Lorenzo