Re: How to Programmatically Change a Property in DesignMode - C# Discussion Boards

Re: How to Programmatically Change a Property in DesignMode

31-Jul-07 10:12

This is the normal behaviour:

When you double-click an the Visible property of a UserControl, Visual Studio will emboldens the altered property, and enable the Undo menu item, and even prompt you to save if you attempt to close - all indicating that a change has been made.

But during DesignMode:

When I programmatically (using ControlDesigner) change the Visible property of a MyUserControl, there is no indication that a change has been made, and Visual Studio does not save the changes. Even though I can see that the property value has changed, it doesn’t go bold or get serialized/saved.

How do you fix it please.

If I'm missing some detail, please let me know.

Any comments are welcomed.

Soog.

Martin#31-Jul-07 12:15

Re: How to Programmatically Change a Property in DesignMode

31-Jul-07 12:15

Hello,

A bold entry at design time property, means that the actual value is != the DefaultValue (Which is an Attribute on the property).
It also means, that this property is written in the "InitializeComponents()".

This behaviour is only possible if you change the properties value over the Designer, it will have no effect id you change it programmaticaly.

All the best,

Martin

Cnight Stalker31-Jul-07 12:57

Re: How to Programmatically Change a Property in DesignMode

31-Jul-07 12:57

Thank you for the prompt reply, Martin.

But, there most be a way to force the property to a Dirty state, and make the IDE serialize/save it. This behaviour is vital to the TabControl that I'm working on, because the Visible property of a currently selected TabPage most be programmatically changed through the TabControlDesigner.

Again, any comments are appreciated.

Thanks in advance,

Soog.

Martin#31-Jul-07 20:46

Re: How to Programmatically Change a Property in DesignMode

31-Jul-07 20:46

Hello,

I think in this case:
TabControl, saves the SelectedIndex, not the Visible states of the TabPages

All the best,

Martin

Cnight Stalker1-Aug-07 10:18

Re: How to Programmatically Change a Property in DesignMode

1-Aug-07 10:18

I see, I guess.

The thing is, I don't know how to go about implement this Confused | :confused:

. I've been trying, but don't quite understand it Sigh | :sigh:

.

Thanks again,

Soog.

Martin#1-Aug-07 20:56

Re: How to Programmatically Change a Property in DesignMode

1-Aug-07 20:56

I think, you have to explain what you want to do a little more detailed.
Maybe show us some codesnipped, what you have done so far!

All the best,

Martin

Cnight Stalker2-Aug-07 15:08

Re: How to Programmatically Change a Property in DesignMode

2-Aug-07 15:08

Yata!
I did it Big Grin | :-D

.

The solution, in one word (or phrase) was DesignerTransaction.

After inspecting the Add and Remove events in my DesignerControl, I devised what you can see in the following snippets, which works perfectly:

[Designer(typeof(MyTabControlDesigner))]
public class MyTabControl : UserControl
{
	protected override void OnMouseDown(MouseEventArgs e)
	{
		if ((tabPageNext = GetHitTest(e.Location)) != null)
		{
			tabPageLast = TabPageFocused;
			if (DesignMode)
			{
				ISelectionService s = (ISelectionService)GetService(typeof(ISelectionService));
				ArrayList a = new ArrayList();

				a.Add(tabPageNext);
				s.SetSelectedComponents(a);
			}
			else
				OnSelectionChanged();
		}
		base.OnMouseDown(e);
	}

	internal void OnSelectionChanged()
	{
		// update focused page
		TabPageFocused = tabPageNext;
	}

	// return true once a selection is freshly made
	internal bool SelectionIsFresh()
	{
		if (TabPageFocused != tabPageLast)
			return false;
		tabPageLast = new TabPageEx();
		
		return true;
	}

internal class MyTabControlDesigner : ControlDesigner
{
	void OnSelectionChanged(object sender, System.EventArgs e)
	{
		IDesignerHost dh = (IDesignerHost)GetService(typeof(IDesignerHost));
		IComponentChangeService cs = (IComponentChangeService)GetService(typeof(IComponentChangeService));
		DesignerTransaction dt;
		
		// validate selection
		if (!tabControl.SelectionIsFresh())
			return;
		// forward a selection event to the control
		dt = dh.CreateTransaction("Select MyTabPage");
		cs.OnComponentChanging(tabControl, null);
		//
		tabControl.OnSelectionChanged(); // updates to the control happens here, dt record it for IDE Undo
		//
		cs.OnComponentChanged(tabControl, null, null, null);
		dt.Commit();
	}

I hope this helps anyone else in a similar situation.

Thank you for your assistance, Martin Rose | [Rose]

, the only person who cared during my plight Cool | :cool:

.

Soog.

Martin#2-Aug-07 20:43

Updating/changing Items in a ListBox with a TextBox

2-Aug-07 20:43

Well Done!

Happy it works for you now!
Got my '5' for sharing it with the community.

All the best,

Martin

stephan.smolek31-Jul-07 9:49

stephan.smolek

31-Jul-07 9:49

Hello,
I currently have the problem that I want to update the contents (a string) of an item of a listbox with a textbox. Best would be on-the-fly so I tried listBox1.Items[listBox1.SelectedIndex] = textBox1.Text in TextChanged.
However I also want to be able to select which item to update by selecting the item in that very listbox. So I do something like textBox1.Text = listBox1.Items[listBox1.SelectedIndex] in SelectedIndexChanged of the listbox. (I say "something like" because the information includes other numbers that are also stored in a list along with the text.)
The problem with that is that selecting an item changes the text in the textbox and that again updates the item which implicitly calls an SelectedIndexChanged again (or so it seems). And during that updating of the listbox it happens that the selectedindex changes to -1. Which is a problem if you try to read that item...
I was wondering if there is an easier/better/cleaner way to accomplish what I try? Confused | :confused:

Stephan

Re: Updating/changing Items in a ListBox with a TextBox

bit_cmdr31-Jul-07 11:00

bit_cmdr

31-Jul-07 11:00

Simple fix, just add if (listBox1.SelectedIndex > -1) so that the conditional is evaluated before making any updates. This should resolve your issue and update the reruired data. For example:

<br />
private void textBox1_TextChanged(object sender, EventArgs e)<br />
{<br />
    if (listBox1.SelectedIndex > -1)<br />
    {<br />
        listBox1.Items[listBox1.SelectedIndex] = textBox1.Text;<br />
    }<br />
}<br />
<br />
private void listBox1_SelectedIndexChanged(object sender, EventArgs e)<br />
{<br />
    if (listBox1.SelectedIndex > -1)<br />
    {<br />
        textBox1.Text = listBox1.Items[listBox1.SelectedIndex].ToString();<br />
    }<br />
}<br />

-Arcond

Re: Updating/changing Items in a ListBox with a TextBox

stephan.smolek31-Jul-07 20:44

stephan.smolek

31-Jul-07 20:44

Thanks for your answer, I found another solution myself today. Smile | :)

Stephan

Average image brightness

newb2vb31-Jul-07 9:41

newb2vb

31-Jul-07 9:41

Hello,

I am looking for a fast and efficient way to read the overall/average brightness of a 640x480 JPEG image. Quick background, I have a CCTV camera outside my house that I can control through ActiveX control in my application. I have code to grab a sample image every x minutes. I then want to read the overall brightness of this sample image to determine if it is dark, bright, etc... so I can adjust gain on the camera, etc... Later I can create a set of parameters to map brightness value ranges to approximate time of day and camera settings.

I understand from what I have read that GetPixel is very slow and that some unsafe code may be quicker but I am still new to image processing in C# so I don't fully understand that.

I have written this code and it works but as you can see, it returns to me (via the messagebox) the brightness of each pixel as it iterates through the loop. This is really annoying because because it kept popping up a messagebox for every pixel and there was no way I was going to sit there and hit "OK" for the whole 640X480 image - so i had to end task. I will pause so you can finish laughing at me, it was a stupid mistake.

public void LoadImage()
{
string strFileName;

strFileName = textBox1.Text;
Bitmap original_bitmap = new Bitmap(strFileName);
pictureBox1.Image = original_bitmap;

Color pixel;

float b;

for (int y = 0; y < pictureBox1.Image.Height; y++)
{
for (int x = 0; x < pictureBox1.Image.Width; x++)
{
//Get a pixel from the image
pixel = original_bitmap.GetPixel(x, y);
//read brightness of pixel
b = pixel.GetBrightness();
//convert float value of pixel to string
string result = b.ToString();
//show pixel brightness to user
MessageBox.Show(result);

}

}

}

At any rate, how do I calculate and output the overall image brightness and not just the brightness of each individual pixel? For now I would like to output to a messagebox for my benefit but later I can obviously store it in a variable to be used by my app. Is the way I am doing it going to be fast enough without having to learn the unsafe code method?

Thanks in advance!!!

Mike

Christian Graus31-Jul-07 11:39

Christian Graus

31-Jul-07 11:39

newb2vb wrote:
JPEG

The JPEG is irrelevant, it's decompressed to a bitmap in memory.

newb2vb wrote:
I then want to read the overall brightness of this sample image to determine if it is dark, bright, etc...

You may want to convert your pixels to HLS, in order to work out brightness. Then you can check luminance.

newb2vb wrote:
. I will pause so you can finish laughing at me, it was a stupid mistake.

Not at all, it was a viable way to test your code and see what the result was. I'd have used Console.WriteLine and checked the result coming out in the IDE, but either way, it's just test code.

newb2vb wrote:
I understand from what I have read that GetPixel is very slow and that some unsafe code may be quicker but I am still new to image processing in C# so I don't fully understand that.

Yes, you should lock the bits and iterate over them.

My image processing articles will show you how to iterate over the bits of an image, and I have one on converting between RGB and HLS as well. To calculate overall brightness, I'd add the lumanance of each pixel and work out the average across the bitmap.

Christian Graus - Microsoft MVP - C++

"I am working on a project that will convert a FORTRAN code to corresponding C++ code.I am not aware of FORTRAN syntax" ( spotted in the C++/CLI forum )

newb2vb31-Jul-07 12:15

newb2vb

31-Jul-07 12:15

Christian,

Thank you for the answer, this helps alot. Just one more question if you don't mind.

The way the sample code I attached in my first message shows, the code will loop through x first from 0 to 640, then it will work y from 0 to 480. I understand what you suggested above to do a simple add and divide by to get the average. How do you recommend I buffer/add all 640 iterations on the first loop, x (then divide by 640) and then do the same for y? Or do I have the concept right but am approaching it all wrong?

Thanks,

Mike

Christian Graus31-Jul-07 17:32

Christian Graus

31-Jul-07 17:32

I'd just keep a running total and then divide it. Your only issue is if the number of pixels means a high value would be bigger than the max of an unsigned int. Then you need to be more creative.

Christian Graus - Microsoft MVP - C++

"I am working on a project that will convert a FORTRAN code to corresponding C++ code.I am not aware of FORTRAN syntax" ( spotted in the C++/CLI forum )

newb2vb31-Jul-07 14:19

newb2vb

31-Jul-07 14:19

Christian,

This simple problem is kicking my butt!!!! I figured out how to do all of the math and sum everything up then divide at the end and I got the code working!

However, the getpixel method as we already knew it would be, was very slow to give me the message box at the end with the one average number.

Therefore, I agree that I should be locking the image and I have now done that and I can get my x and y loops working going through the image no problem. However, when the unsafe/locked image approach is used, you can no longer use pixel.getbrightness like I could do using the other message (error says that image has already been locked.

So the last question I have is, if I have locked my image and can iterate through each pixel using the unsafe/locked method, how do I read the brightness of each pixel?

Thanks again!

Mike

Christian Graus31-Jul-07 17:33

Christian Graus

31-Jul-07 17:33

You would iterate over the bits of the image, which are the r/g/b components ( actually, they are b/g/r in memory ) and then convert the resultant color to HLS, using the code from my article on color spaces.

Christian Graus - Microsoft MVP - C++

"I am working on a project that will convert a FORTRAN code to corresponding C++ code.I am not aware of FORTRAN syntax" ( spotted in the C++/CLI forum )

C# Multithreading, GUI hangs while loading

Luc Pattyn31-Jul-07 13:53

Luc Pattyn

31-Jul-07 13:53

Hi,

here is another idea to speed things up.

you could create a smaller image based on the image you have
using the constructor
public Bitmap (
Image original,
int width,
int height
)
say you reduce by 8 in both directions (640*480 --> 80*60)

Now get the brightness of every pixel, and average that (accumulate them all in a
float, divide by width*height at the end).

I expect a significant speed gain, while the reduction should have little or no
influence on the image brightness.

Remark: I have not done this myself yet...

Smile | :)

Luc Pattyn

try { [Search CP Articles] [Search CP Forums] [Forum Guidelines] [My Articles] }
catch { [Google] }

Justincc31-Jul-07 7:11

Justincc

31-Jul-07 7:11

My Code below is using a backgroundWorker component. My entire GUI freezes while it loads the content tree from the database. The window even says (not responding) at the top.

My desired result is to have a loading animation play while loading the data from the database... am I going at this wrong? Shouldn't the loading take place in the background, preventing the GUI from freezing up?

Any ideas?

___________________________________________________________

private void bgWorker_DoWork(object sender, DoWorkEventArgs e)
{
LoadCompanies();
}

private void bgWorker_RunWorkerCompleted(object sender, RunWorkerCompletedEventArgs e)
{
ShowLoadingAnimation(false);
}

private void LoadCompanies(object sender, EventArgs e)
{
ShowLoadingAnimation(true);
this.bgWorker.RunWorkerAsync();
}

private delegate void LoadCompaniesDelegate();

public void LoadCompanies()
{
PROSOCO.Library.Companies.Criteria criteria = PROSOCO.Library.Companies.Criteria.GetCriteria();

BindingSource src = new BindingSource();

PROSOCO.Library.Companies.Nodes nodes = PROSOCO.Library.Companies.Nodes.GetNodes(criteria.NodeCriteria());

src.DataSource = nodes;

if (pnlNavigation.InvokeRequired)
{
LoadCompaniesDelegate find = new LoadCompaniesDelegate(LoadCompanies);
this.Invoke(find, new object[] { });
}
else
{
pnlNavigation.ContentTree.ParentMember = "ParentId";
pnlNavigation.ContentTree.ValueMember = "Id";
pnlNavigation.ContentTree.DisplayMember = "Name";
pnlNavigation.ContentTree.PrefixMember = "CustomerNumber";
pnlNavigation.ContentTree.PostfixMember = "CityState";
pnlNavigation.ContentTree.DataSource = src;
}

_activeModule = "Companies";

}

Luc Pattyn31-Jul-07 7:22

Luc Pattyn

31-Jul-07 7:22

Hi,

you seem aware of the fact that controls are not thread-safe, so you try
to use InvokeRequired and Invoke(), but IMO there are some mistakes in the
implementation\; the normal pattern is a method that ONLY contains something like

if (InvokeRequired) Invoke(delegate)
else do_whatever_needs_to_be_done_to_the_GUI

Your public void LoadCompanies() method however contains stuff before the if;
that stuff will execute twice, the second time on the GUI (bad for responsiveness);
it also generates two BindingSource objects, only the second one will be used.

I suggest you split the method in two parts, i.e. move the second half
(the if-else) to a separate method, and apply the pattern to it, hence avoiding
the first half to be executed twice (of which once on the GUI)

Smile | :)

Luc Pattyn

try { [Search CP Articles] [Search CP Forums] [Forum Guidelines] [My Articles] }
catch { [Google] }

Justincc31-Jul-07 7:29

Justincc

31-Jul-07 7:29

It still has the same isse.

I'm not sure I understood your suggestion, but I updated it as shown below. However, the gui still hangs while loading the companies.

public void LoadCompanies()
{
if (pnlNavigation.InvokeRequired)
{
LoadCompaniesDelegate find = new LoadCompaniesDelegate(LoadCompanies);
this.Invoke(find, new object[] { });
}
else
{
PROSOCO.Library.Companies.Criteria criteria = PROSOCO.Library.Companies.Criteria.GetCriteria();
BindingSource src = new BindingSource();
PROSOCO.Library.Companies.Nodes nodes = PROSOCO.Library.Companies.Nodes.GetNodes(criteria.NodeCriteria());
src.DataSource = nodes;
pnlNavigation.ContentTree.ParentMember = "ParentId";
pnlNavigation.ContentTree.ValueMember = "Id";
pnlNavigation.ContentTree.DisplayMember = "Name";
pnlNavigation.ContentTree.PrefixMember = "CustomerNumber";
pnlNavigation.ContentTree.PostfixMember = "CityState";
pnlNavigation.ContentTree.DataSource = src;
}

_activeModule = "Companies";
}

PhilDanger31-Jul-07 7:38

PhilDanger

31-Jul-07 7:38

This still makes it execute on the GUI thread.

One idea would be to run everything but the actual GUI stuff in the background. When BackgroundWorker finishes, you can return the data that you need to load the GUI stuff (Binding Source) through the DoWorkEventArgs.Result (which gets sent to the RunWorkerCompletedEvent when it finish DoWork). You then cast the Result to a BindingSource and do the last portion of your code (after src.DataSource = nodes; ) in the GUI thread.

Justincc31-Jul-07 10:05

Justincc

31-Jul-07 10:05

I am new to C# so forgive me for not "just getting it" but this is what I have so far. I am doing something wrong because "BindingSource src = (BindingSource)e.Result;" Doesn't seem to be loading any data...

Did I atleast get everything running in the background except the GUI stuff?
Can you tell why I wouldn't be loading any data?

Thanks in advance.

<br />
 private delegate object LoadCompaniesDelegate();<br />
<br />
        public object LoadCompanies()<br />
        {<br />
            BindingSource src = new BindingSource();<br />
            if (pnlNavigation.InvokeRequired)<br />
            {<br />
                LoadCompaniesDelegate find = new LoadCompaniesDelegate(LoadCompanies);<br />
                this.Invoke(find, new object[] { });<br />
            }<br />
            else<br />
            {<br />
                PROSOCO.Library.Companies.Criteria criteria = PROSOCO.Library.Companies.Criteria.GetCriteria();                <br />
                PROSOCO.Library.Companies.Nodes nodes = PROSOCO.Library.Companies.Nodes.GetNodes(criteria.NodeCriteria());                <br />
                src.DataSource = nodes;<br />
                MessageBox.Show("Loaded Notes");<br />
            }<br />
            return src;<br />
        }       <br />
        private void bgWorker_DoWork(object sender, DoWorkEventArgs e)<br />
        {<br />
            e.Result = LoadCompanies();<br />
        }<br />
        private void bgWorker_RunWorkerCompleted(object sender, RunWorkerCompletedEventArgs e)<br />
        {<br />
            BindingSource src = (BindingSource)e.Result;<br />
            pnlNavigation.ContentTree.ParentMember = "ParentId";<br />
            pnlNavigation.ContentTree.ValueMember = "Id";<br />
            pnlNavigation.ContentTree.DisplayMember = "Name";<br />
            pnlNavigation.ContentTree.PrefixMember = "CustomerNumber";<br />
            pnlNavigation.ContentTree.PostfixMember = "CityState";<br />
            pnlNavigation.ContentTree.DataSource = src;<br />
            _activeModule = "Companies";<br />
<br />
            MessageBox.Show("Completed");<br />
        } <br />