Re: Question about form designer - C# Discussion Boards

Re: difference b/w readonly and const?

Marcelo Calado24-Jan-07 11:31

Marcelo Calado

24-Jan-07 11:31

This link could help you:

http://blogs.msdn.com/csharpfaq/archive/2004/12/03/274791.aspx[^]

Do you need develop a Professional Software with low cost? Contact me!

Re: difference b/w readonly and const?

Rahithi24-Jan-07 14:05

Rahithi

24-Jan-07 14:05

Thanks to all who answered my question. now i came to know what is the difference b/w read-only & a constant.

Thanks,
Rahi

If you look at what you do not have in life, you don't have anything,
If you look at what you have in life, you have everything... "

C# PictureBox.MouseDown

kselman24-Jan-07 10:25

kselman

24-Jan-07 10:25

I hope this is an easy one. It seems like it should be.

I have a pictureBox that I am using as a button. I'm swapping images in and out for up and down states. When the user clicks and holds the mouse down I want it to execute the MouseDown code multiple times until they MouseUp.

<br />
private void mirrorAdjust_MouseDown(object sender, MouseEventArgs e)<br />
{<br />
    mirrorPictureBox.Image = Resources.MirrorDown;<br />
    <br />
    //while(MouseDown) ?? Is there a state I can check here?<br />
    FunctionToRepeatUntilMouseUp();<br />
}<br />
<br />
private void mirrorAdjust_MouseUp(object sender, MouseEventArgs e)<br />
{<br />
    mirrorPictureBox.Image = Resources.MirrorUp;<br />
}<br />

Re: C# PictureBox.MouseDown

Martin#24-Jan-07 10:31

Martin#

24-Jan-07 10:31

Hello,

In this case you have to work with a timer. (System.Windows.Forms.Timer for example)

You set the Enable Property true at Mouse Down.
In the tick event code you than add the mousedown code.
At mouse up you have to set Enable to false. (Also at MouseLeave to be sure)

Hope that helps,

All the best

Martin

Re: C# PictureBox.MouseDown

kselman24-Jan-07 11:29

kselman

24-Jan-07 11:29

Thanks for the quick reply!

Sounds good I will use a Timer then..

Thanks
-Kevin

Re: C# PictureBox.MouseDown

Luc Pattyn24-Jan-07 15:20

Luc Pattyn

24-Jan-07 15:20

I have not done this, but I expect you can use a regular Button, give it no text,
but add a picturebox to its Controls property, hence combining the best of both.

Smile | :)

Luc Pattyn

Question about form designer

reutre24-Jan-07 10:19

reutre

24-Jan-07 10:19

I'm writing a form based app using the tab control. I want to make the app as modular as possible so it will be easy to modify and extend.

My intention is to subclass TabPage and design each tab separately so it can be "plugged in" to the main app (at compile time, not run time). Ideally, my subclassed TabPage would be usable in the form designer to lay out the controls for that tab.

In practice, however, I'm finding that form designer will not display my subclassed TabPage in design view, it will only show me the controls present on the page as icon view. My question is this: Is there any way to make my subclassed TabPage show up in form designer the way I want?

Thanks,

Trent R

Re: Question about form designer

Ed.Poore24-Jan-07 12:40

Ed.Poore

24-Jan-07 12:40

One solution would be to use a UserControl / Panel which would allow you to lay out the controls as you want.

You could then either load this custom control onto a tab page, or you could simply change the inherited class from UserControl to TabPage, hopefully the layout logic that was generated by the designer will remain there (it might disappear though if you try and re-load it into the designer).

The safest would probably be to use a UserControl as the "subclassed" TabPage and then simply drop this onto an existing tab page.

I have no idea what I just said. But my intentions were sincere.

Poore Design

SelectionStart error on custom TextBox...

Lord Kixdemp24-Jan-07 10:04

Lord Kixdemp

24-Jan-07 10:04

Hello everyone! Big Grin | :-D

I'm trying to make a custom text box for currencies... It instantiates this control:

http://www.codeproject.com/useritems/FilterTextBox.asp

I never made a custom control before, so these are my exact steps: :P

1. Go to Project->New
2. Select 'Windows Control Library' and click OK
3. Add a reference to FilterTextBox.
4. Change UserControl to FilterTextBox on both partial classes.
5. It gave me an error on compile, so I had to remove the second line inside InitializeComponent() on file UserControl1.Designer.cs:
this.AutoScaleMode = System.Windows.Forms.AutoScaleMode.Font;
6. I typed in my custom code:

public CurrencyTextBox()
		{
			// Digits only
			MustContain = ".0123456789";
			InitializeComponent();
		}

		void OnEnter(EventArgs e)
		{
			base.OnEnter(e);

			double a = Convert.ToDouble(Text);
			this.BackColor = Color.Aqua;

			Text = a.ToString();
		}

7. I add the DLL to my program's References and to the Toolbox, but when I try and drag it to my form I get this message:

InvalidArgument=Value of '-1' is not valid for 'SelectionStart'.<br />
Parameter name: SelectionStart

Hmm... I got this message a bit ago as an exception when using a FilterTextBox, in my Leave event handler for that control... Maybe there's a problem with me making my own OnEnter? Help! Thanks! Wink | ;)

Windows Calculator told me I will die at 28. Frown | :(

Re: SelectionStart error on custom TextBox...

Martin#24-Jan-07 10:20

Martin#

24-Jan-07 10:20

Hello,

I think the error you made, is choosing this FilterTextBox!
There are much better articles here on CP.

After a quick search I found code like:

this.SelectionStart = p-1;

Without any validation before.

So really I think the error comes from the Control youre usercontrols inherit from.

P.S.: You should use double.TryParse instead of Convert.ToDouble.

All the best,

Martin

Re: SelectionStart error on custom TextBox...

Lord Kixdemp24-Jan-07 11:58

Lord Kixdemp

24-Jan-07 11:58

Hmm... yeah, there are a few... Which do you recommend? I don't wanna choose a bad one again... Thanks! Wink | ;)

Windows Calculator told me I will die at 28. Frown | :(

Re: SelectionStart error on custom TextBox...

Martin#24-Jan-07 19:42

Martin#

24-Jan-07 19:42

Hello,

http://www.codeproject.com/info/search.asp?cats=3&searchkw=Numeric+TextBox&Submit1=Search&author=&sd=15+Nov+1999&ed=25+Jan+2007[^]

The first and second looks good.

All the best,

Martin

Re: SelectionStart error on custom TextBox...

Lord Kixdemp27-Jan-07 16:41

Lord Kixdemp

27-Jan-07 16:41

OK, I'll try 'em! Thanks! Wink | ;)

Windows Calculator told me I will die at 28. Frown | :(

Checking if a handler is sbuscribed to an event

Dan Neely24-Jan-07 9:42

Dan Neely

24-Jan-07 9:42

Can I check if a given handler is assigned to an event.

I'm having problems with events I want to fire in most cases, but not under a few specific instances. I'm currently using InstallFooHandlers() and RemoveFooHandlers() to control the firing, but the system breaks down in one case where methods Bar() and Baz() both need the handlers disabled, but Bar() calls Baz() internally, because at their conclusion's both methods install the handlers resulting in two copies being attached to each event and the next pass through not removing them. Putting a pair of install/remove calls around Bar()'s call of Baz() would work but I'd prefer something less kludgey if possible.

--
Rules of thumb should not be taken for the whole hand.

Re: Checking if a handler is sbuscribed to an event

Abisodun24-Jan-07 10:07

Abisodun

24-Jan-07 10:07

I think if you override the handler in a sub class you can use the new delegate to check for listeners.

public partial class myButton : Button
{
public myButton()
{
InitializeComponent();
}

public event ClickHandler Click1;
public delegate void ClickHandler(EventArgs e);

public myButton(IContainer container)
{
container.Add(this);

InitializeComponent();

}

protected override void OnClick(EventArgs e)
{
if (null != Click1)
Click1(e);

base.OnClick(e);
}

public bool HasListener
{
get { return (null != Click1); }
}
}

Datasets from SQL data

~~~Johnny~~~24-Jan-07 9:09

~~~Johnny~~~

24-Jan-07 9:09

I was wondering if there was something simpler to do

When you create a dataset from reading in SQL database for string values you obtain a column with th full lenght of the SQL column, thus when you bind to a Textbox you do have spaces at the right end of the data.

I can use RTRIM(data) in the SQL statetment of course but is there an easier way to trim I don't know about ?
Confused | :confused:

Re: Datasets from SQL data

Christian Graus24-Jan-07 9:11

Christian Graus

24-Jan-07 9:11

Use nvarchar, then there's no padding.

Christian Graus - C++ MVP

'Why don't we jump on a fad that hasn't already been widely discredited ?' - Dilbert

How to call external application in C#.NET

Eyungwah24-Jan-07 8:34

Eyungwah

24-Jan-07 8:34

Hello All:

In C#.NET 2005, I have created a Button on the Form. When the user click on the Button, it will execute an external application. Could someone pleasae help me how would I go about doing that. Thanks in advance.

Re: How to call external application in C#.NET

Pete O'Hanlon24-Jan-07 8:37

Pete O'Hanlon

24-Jan-07 8:37

Use Process.Start.

the last thing I want to see is some pasty-faced geek with skin so pale that it's almost translucent trying to bump parts with a partner - John Simmons / outlaw programmer

Deja View - the feeling that you've seen this post before.

Re: How to call external application in C#.NET

dbrenth24-Jan-07 8:44

dbrenth

24-Jan-07 8:44

Look at the System.Diagnostics.Process object. It should have everything you need.

Brent

Re: How to call external application in C#.NET

Eyungwah24-Jan-07 13:32

Eyungwah

24-Jan-07 13:32

Thank you for your reply guys.. Smile | :)

I used the proc = System.Diagnostics.Process.Start("C:\\xxxx.exe"); That part works fine.

One more question though - I need to add parameter with that external application. How can I do that??

Thanks again for your help.

Re: How to call external application in C#.NET

Shajeel24-Jan-07 19:29

Shajeel

24-Jan-07 19:29

http://www.codeproject.com/csharp/start_an_external_app.asp[^]

Regards
Shajeel

Re: How to call external application in C#.NET

Seishin#25-Jan-07 3:27

Seishin#

25-Jan-07 3:27

there's an overload:

System.Diagnostics.Process.Start("C:\\xxxx.exe", "parameters");

life is study!!!

How to call external application in C#.NET

Eyungwah24-Jan-07 8:28

Eyungwah

24-Jan-07 8:28

[No Message]

Comparing large amounts of binary data

sbpont24-Jan-07 8:27

sbpont

24-Jan-07 8:27

I am comparing disk files to see if they are the same. (I don't care about the details, I just want a yes/no result.) Currently, I am loading a pair of byte arrays with System.IO.FileStream.Read() and then comparing them using a for loop. This works, but I was wondering if there is a more efficient way to handle it. The current implementation seems to be pretty slow. (I haven't been able to find the .NET equivalent of "memcmp".)

Also, how much of a factor is the array size? Is it better to read 1KB at a time from a file or 1MB?

Thanks!

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