Monday, July 23, 2007

Displaying the Calendar view on a DateTimePicker Control in .NETCF

I've recently made a solution where the customer requested to be able to bring up the calendar view in a DateTimePicker control by pressing on a specific button on the screen. The solution to that was really simple: Create a control that inherits from System.Windows.Forms.DateTimePicker and add a method called ShowCalendar() which I call to bring up the Calendar view.

public class DateTimePickerEx : DateTimePicker
  static extern int SendMessage(
    IntPtr hWnd, uint uMsg, int wParam, int lParam);

  const int WM_LBUTTONDOWN = 0x0201;

  public void ShowCalendar() {
    int x = Width - 10;
    int y = Height / 2;
    int lParam = x + y * 0x00010000;

    SendMessage(Handle, WM_LBUTTONDOWN, 1, lParam);


Jenson said...

Hi Christian,

It's Jenson here.

Hmm, sorry I'm quite new in coding and I found out that I'm always scared of coding something like this, which I have no knowledge or experience on:

SendMessage(Handle, WM_LBUTTONDOWN, 1, lParam);

Are they native codes or something else?I don't really know how to name them. I think you are either a C# guy, or you have background on Java, I've been trying hard to squeeze out time to learn Java too -.-"

Great blog and resources >.<" can learn a lot from here.

One more thing, your photo is so cool XD

Christian Resma Helle said...

Hi Jenson,

Nice of you to stop by. And thanks for all the compliments.

WM_LBUTTONDOWN is the Windows Message that a control receives when it is clicked using the left mouse button. Windows programming can be quite cryptic to see at first.

Try reading up on Win32 Programming a little, you will see the bigger picture and you might also thank god for managed code!

As for my programming background, i mainly work with C# now but i've played with quite a few other technologies in the past. I never really got proficient with Java though. I believe that Java was a part of my Linux phase..

Jenson said...

yeah, it's always my pleasure to visit blogs, especially those who has helped me a lot. I'll find myself rude if I stop by and say Hi to you =)

Well, there will be another project coming in pretty soon. I will be quite busy soon -.-"

And yeah, thanks God for the managed code, else I will have to remember all these WM_LBUTTONDOWN stuff, btw, the new project would use purely PDA for client side, so might be Windows CE 6.0 as they dont need the mobile functions.

Have a nice day! Take care!

Anonymous said...

I'm realy trying hard to translate this to VS2008 - and can't get it work - can anybody help ?