Make user control display outside of form boundry

I've decided to reimplement the datetime picker, as a standard datetime picker isn't nullable. The user wants to start with a blank field and type (not select) the date.

I've created a user control to do just that, but if the user control is near the edge of the form, it will be cut off on the form boundry. The standard datetime picker doesn't suffer from this problem.

Here is a picture showing the problem. My user control is on the left, the standard datetimepicker is on the right:

As you can see, the standard control will display over the form AND application boundry. How do I get the month picker in my control to do the same thing?

Thanks!

From stackoverflow

• Simply set the z-layer value for it (CSS), like so:

  style="z-layer:1;"

  Tigraine : I think he's talking about Winfoms

  deadcat : yes, it is winforms. My original post was incorrect, sorry! I need more sleep.. it is midnight here....

• This is a CSS problem.

  You should set the z-index on the div containing the popup calendar. Have a look at the tutorial on w3schools:

  http://www.w3schools.com/Css/pr_pos_z-index.asp

  EDIT: Now that you've realised you're actually using WinForms, please ignore my answer :)

• The screenshots looks like a Windows Forms applications, so my answer is for winforms.

  I guess the best solution would be to create a customcontrol that itself uses the datetime picker that already has the behavior.

  Show a empty textbox until it gets clicked, then display the datetimepicker.

  That would save you a bunch of code..

  deadcat : That's a good suggestion, I will give that a try tomorrow. I'm still keen to know if there is a way to answer my original question though! :)

  deadcat : This custom control should do the trick: http://www.codeguru.com/csharp/csharp/cs_controls/custom/article.php/c9645

  deadcat : It turned out I couldn't go down this path. I started with the control above, but there is no way to set the control up so that the user can tab to it and start typing - an important feature for the user I am writing for.

• I'm not 100% sure, but a quick look at the DateTimePicker class on Reflector takes me to the SafeNativeMethods.SetWindowPos internal class.

  You can override the SetBoundsCore from the base Control class or, like Tigraine stated, create a custom control based on the DateTimePicker.

  Hope it helps, Bruno Figueiredo

• I ran into this when trying to implement a custom control and discovered that it's a remarkably hard problem. There's no built-in functionality within the Windows.Forms model to support controls whose display area extends outside the client area of their container.

  You basically have to either use the Windows API or draw your controls inside a Form with AlwaysOnTop set. Both approaches are harder than they should be. I ended up redesigning my control so that instead of displaying its expanded contents in a dropdown it used a modal dialog. This was a pretty unsatisfying solution, but I spent a couple of weeks trying other approaches and could never get anything that worked consistently across all use cases (like disappearing when the application loses focus).

• The reason that your control gets chopped off is because it is a child control of the form that you reside on. Any control on the form must be contained by the form, hence it gets chopped off.

  I haven't done this in .Net, but had a similar problem in VB6. The solution then was to set the parent of the popup window (the calendar in your case) to be the desktop. This will allow it to extend beyond the boundaries of your form. You'll have to do some P/Invoke magic to find the hWnd of the popup, and another P/Invoke to set the parent.

• The ToolStripDropDown control has this functionallity so by inheriting from it we can make a simple PopupWindow.

  /// <summary>
  /// A simple popup window that can host any System.Windows.Forms.Control
  /// </summary>
  public class PopupWindow : System.Windows.Forms.ToolStripDropDown
  {
      private System.Windows.Forms.Control _content;
      private System.Windows.Forms.ToolStripControlHost _host;
  
      public PopupWindow(System.Windows.Forms.Control content)
      {
          //Basic setup...
          this.AutoSize = false;
          this.DoubleBuffered = true;
          this.ResizeRedraw = true;
  
          this._content = content;
          this._host = new System.Windows.Forms.ToolStripControlHost(content);
  
          //Positioning and Sizing
          this.MinimumSize = content.MinimumSize;
          this.MaximumSize = content.Size;
          this.Size = content.Size;
          content.Location = Point.Empty;
  
          //Add the host to the list
          this.Items.Add(this._host);
      }
  }
  

  Usage:

  PopupWindow popup = new PopupWindow(MyControlToHost);
  popup.Show(new Point(100,100));
  ...
  popup.Close();
  

  deadcat : Holy crap, this code is the most awesome code ever. I'm integrating this into my user control, thanks.

  deadcat : I got it working. Is there anyway to remove the border?

  jblaske : I've implemented this code, but the popup keeps stealing focus. Is there a way to prevent this?