Databases
StackOverflow2013
Postsdbo
PO
 

Note that there are some explanatory texts on larger screens.

plurals
  1. PO
    primarykey
    data
    text
    <p>I was recently wanting to put Drag and Drop functionality in my project and I hadn't come across this issue, but I was intrigued and really wanted to see if I could come up with a better method than the one described in the page you linked to. I hope I clearly understood everything you wanted to do and overall I think I succeeded in solving the problem in a much more elegant and simple fashion.</p> <p>On a quick side note, for problems like this it would be great if you provide some code so we can see exactly what it is you are trying to do. I say this only because I assumed a few things about your code in my solution...so hopefully it's pretty close.</p> <p>Here's the code, which I will explain below:</p> <pre><code>this.LabelDrag.QueryContinueDrag += new System.Windows.Forms.QueryContinueDragEventHandler(this.LabelDrag_QueryContinueDrag); this.LabelDrag.MouseDown += new System.Windows.Forms.MouseEventHandler(this.LabelDrag_MouseDown); this.LabelDrag.MouseUp += new System.Windows.Forms.MouseEventHandler(this.LabelDrag_MouseUp); this.LabelDrop.DragDrop += new System.Windows.Forms.DragEventHandler(this.LabelDrop_DragDrop); this.LabelDrop.DragEnter += new System.Windows.Forms.DragEventHandler(this.LabelMain_DragEnter); public partial class Form1 : Form { public Form1() { InitializeComponent(); } private void LabelDrop_DragDrop(object sender, DragEventArgs e) { LabelDrop.Text = e.Data.GetData(DataFormats.Text).ToString(); } private void LabelMain_DragEnter(object sender, DragEventArgs e) { if (e.Data.GetDataPresent(DataFormats.Text)) e.Effect = DragDropEffects.Copy; else e.Effect = DragDropEffects.None; } private void LabelDrag_MouseDown(object sender, MouseEventArgs e) { //EXTREMELY IMPORTANT - MUST CALL LabelDrag's DoDragDrop method!! //Calling the Form's DoDragDrop WILL NOT allow QueryContinueDrag to fire! ((Label)sender).DoDragDrop(TextMain.Text, DragDropEffects.Copy); } private void LabelDrag_MouseUp(object sender, MouseEventArgs e) { LabelDrop.Text = "LabelDrag_MouseUp"; } private void LabelDrag_QueryContinueDrag(object sender, QueryContinueDragEventArgs e) { //Get rect of LabelDrop Rectangle rect = new Rectangle(LabelDrop.Location, new Size(LabelDrop.Width, LabelDrop.Height)); //If the left mouse button is up and the mouse is not currently over LabelDrop if (Control.MouseButtons != MouseButtons.Left &amp;&amp; !rect.Contains(PointToClient(Control.MousePosition))) { //Cancel the DragDrop Action e.Action = DragAction.Cancel; //Manually fire the MouseUp event LabelDrag_MouseUp(sender, new MouseEventArgs(Control.MouseButtons, 0, Control.MousePosition.X, Control.MousePosition.Y, 0)); } } } </code></pre> <p>I have left out most of the designer code, but included the Event Handler link up code so you can be sure what is linked to what. In my example, the drag/drop is occuring between the labels LabelDrag and LabelDrop.</p> <p>The main piece of my solution is using the QueryContinueDrag event. This event fires when the keyboard or mouse state changes after DoDragDrop has been called on that control. You may already be doing this, but it is very important that you call the DoDragDrop method of the control that is your source and not the method associated with the form. Otherwise QueryContinueDrag will NOT fire!</p> <p>One thing to note is that QueryContinueDrag will actually fire when you release the mouse <em>on the drop control</em> so we need to make sure we allow for that. This is handled by checking that the Mouse position (retrieved with the global Control.MousePosition property) is inside of the LabelDrop control rectangle. You must also be sure to convert MousePosition to a point relative to the Client Window with PointToClient as Control.MousePosition returns a <em>screen relative</em> position.</p> <p>So by checking that the mouse is <em>not</em> over the drop control and that the mouse button is now <em>up</em> we have effectively captured a MouseUp event for the LabelDrag control! :) Now, you could just do whatever processing you want to do here, but if you already have code you are using in the MouseUp event handler, this is not efficient. So just call your MouseUp event from here, passing it the necessary parameters and the MouseUp handler won't ever know the difference.</p> <p>Just a note though, as I call DoDragDrop from <em>within</em> the MouseDown event handler in my example, this code should <em>never</em> actually get a direct MouseUp event to fire. I just put that code in there to show that it is possible to do it.</p> <p>Hope that helps!</p>
    singulars
    1. This table or related slice is empty.
    1. PODoDragDrop and MouseUp
      singulars
      1. PTQuestion
    1. PTAnswer
    1. USLeon Bambrick
    1. USAdam Haile
    plurals
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. PODoDragDrop and MouseUp
      singulars
      1. PTQuestion
    1. This table or related slice is empty.
    1. VO
      singulars
      1. PO
      1. This table or related slice is empty.
      1. VTAcceptedByOriginator
    2. VO
      singulars
      1. PO
      1. This table or related slice is empty.
      1. VTUpMod
    3. VO
      singulars
      1. PO
      1. This table or related slice is empty.
      1. VTUpMod
    1. COlearned a lot from your solution! thanks!
      singulars
      1. PO
      1. USPablo Santa Cruz
    2. COYou're idea is great, thanks! But I think your if statement should look like (button may be in something other than the form, got rid of spurious not): if (Control.MouseButtons != MouseButtons.Left && rect.Contains(button.Parent.PointToClient(Control.MousePosition)))
      singulars
      1. PO
      1. UScolithium
 

Querying!

 
Guidance
A row detail

Detail views are divided into sections. All the information in the data section comes from columns in the selected row. The other sections display data from other, related rows.

Related data can be related in a to-one or a to-many fashion. Captions of data related in a to-many fashion link to a list view showing a filtered view of the table.

Try moving around until you find a non-empty to-many entry and click on the label to get to one. You can move back to the root by clicking on the database name in the header.

SQuiL has stopped working due to an internal error.

If you are curious you may find further information in the browser console, which is accessible through the devtools (F12).

Reload