You can try something like this. I have modified your code slightly to place reading and writing inside the main loop. Also, I recommend having your streams inside a using block, it is simpler to write and safer if any exception is thrown. Note: This code is untested!!

    public static void Download(String strURLFileandPath, String strFileSaveFileandPath)
    {
        HttpWebRequest wr = (HttpWebRequest)WebRequest.Create(strURLFileandPath);
        HttpWebResponse ws = (HttpWebResponse)wr.GetResponse();
        byte\[\] inBuf = new byte\[100000\];
        int bytesToRead = (int)inBuf.Length;
        int bytesRead;
        using (Stream str = ws.GetResponseStream()) 
        {
            using (FileStream fstr = new FileStream(strFileSaveFileandPath, FileMode.OpenOrCreate, FileAccess.Write))
            {
                try
                {
                    while ((bytesRead = str.Read(inBuf, 0, bytesToRead)) > 0) 
                    {
                        fstr.Write(inBuf, 0, bytesRead);
                    }
                }
                catch (Exception e) {
                    MessageBox.Show(e.Message);
                }
            }
        }
    }

What you should do to avoid your buffer overflowing is to read some data to your buffer and then writing to the file, all within a loop. This is a very common technique, for example, to copy files.

You have to take into account that strArray is a reference type. It seems that when you add it to strArrayList, a reference is added. Then, strArrayList contains a list of references to string arrays, which are the same array since you have been reusing the variable without reasignating it. This is similar to what happens in the following case:

public void Test() {
string[] a = new string[] {"", ""};
string[] b = a;
a[0] = "A";
b[0] = "B";
Console.WriteLine("{0} {1}", a[0], b[0]);
}

Difficult to know without all the source code. However, from your description, seems that variable i in function AddText is out of range. You should check that i is positive and less than list1.Length. Something like this

//Function to add string dynamically in Class1
private List list1 = new List();

public void AddText(string myText) {
	if ((i < 0) || (i >= list1.Length)) {
		MessageBox.Show(String.Format("i is {0}. Should be between 0 and {1}", i, list1.Length));
		return;
	}
	if((list1\[i\] == "") && (k < 1)) {
		k = i;
		list1\[i\] = myText;
		k++;
	}
}

By the way, please mind the ampersand in line

	if((list1\[i\] == "") && (k < 1)) {

Also, if you are looping, shouldn't there be a loop somewhere? I can't see it.

I use ExcelLibrary which can be downloaded from Google code

License is GNU LGPL.

Beware of the "}" right after comment "// This is plain wrong - should be false" What is Konstanten?

Sorry for the delay. If you want to keep number of clicks inside the button, all you have to do is subclass Button class and add a field with the number of clicks. Then, override the OnClick method to increase the number of clicks by one every time the button is clicked. Don't forget to call the parent OnClick so that the normal button click behavior is executed. You have an example below.

using System;
using System.Drawing;
using System.Windows.Forms;

class CountClickButton : Button {

int clickCount; // Number of clicks

public CountClickButton() {
	clickCount = 0;
}

// OnClick is called when the button is clicked. It must increase clickCount by one
// and then execute the event handlers (which is done when base.OnClick
// is executed).
protected override void OnClick(EventArgs e) {
	clickCount = clickCount + 1;
	base.OnClick(e);
}

// Only allow other classes to read number of clicks. Number of clicks cannot be
// modified by other classes.
public int ClickCount {
	get {
		return clickCount;
	}
}

}

class CountClickForm : Form {

CountClickButton b;

public CountClickForm() {
	b = new CountClickButton();
	b.Text = "Click me!";
	b.Size = b.PreferredSize;
	ClientSize = new Size(700, 400); // Should be big enough. Fit to your own needs.
	b.Left = (ClientSize.Width - b.Width) / 2;
	b.Top = (ClientSize.Height - b.Height) / 2;
	b.Click += new EventHandler(b\_clicked);
	Controls.Add(b);
	Text = "I count clicks!";
}

// b\_clicked is registered as an event. It will be executed when button is clicked,
// after number of clicks is increased by one.
void b\_clicked(object sender, EventArgs e) {
	string text = String.Format("Button has been clicked {0} times.", b.ClickCount);
	if (b.ClickCount < 1) { 
		// This should never happen.
		text = "Sorry, I was drunk when programming this. Cheers!!";
	}
	if (b.ClickCount == 1) {
		text = "Button has been clicked once.";
	}
	if (b.ClickCount == 2) {
		text = "Button has been clicked twice.";
	}
	Text = text;
}
	
\[STAThreadAttribute\]
static void Main() {
	Application.Run(new CountClickForm());
}

}

In fact, I have. If you have a look at the link you just posted, you will see a note in yellow color which says: "The static keyword has more limited uses than in C++. To compare with the C++ keyword, see Static (C++)." So, if you try the following code, it will not compile in C#

class ClickCount {

static void Main() {
	ClickCount click = new ClickCount();
	click.IncreaseClickCountByOne();
	click.IncreaseClickCountByOne();
	click.IncreaseClickCountByOne();
}

void IncreaseClickCountByOne() {
	static int clickCount = 1;
	clickCount = clickCount + 1;
	Console.WriteLine(clickCount);
}

}

Of course, member variables ( fields ) can be static or nonstatic. Any of them will keep their value between method calls.

class ClickCount {

static int clickCount = 1;

static void Main() {
	ClickCount click = new ClickCount();
	click.IncreaseClickCountByOne();
	click.IncreaseClickCountByOne();
	click.IncreaseClickCountByOne();
}

void IncreaseClickCountByOne() {
	clickCount = clickCount + 1;
	Console.WriteLine(clickCount);
}

}

class ClickCount {

int clickCount = 1;

static void Main() {
	ClickCount click = new ClickCount();
	click.IncreaseClickCountByOne();
	click.IncreaseClickCountByOne();
	click.IncreaseClickCountByOne();
}

void IncreaseClickCountByOne() {
	clickCount = clickCount + 1;
	Console.WriteLine(clickCount);
}

}

Both work exactly in the same way.

Sorry to disagree with you, but this behavior of the static keyword corresponds to C++ and not C#. In fact, if you try to set a local variable ( i.e. defined inside a method ) as static in C#, you will obtain a compiler error. In my opinion, the best option to have clickCount record the number of clicks is to define it as a member variable and not a local one.

That's probably true. In that case

Image im = pb.Image; // Assume pb is your PictureBox
Graphics g = Graphics.FromImage(im);
g.DrawRectangle(Pens.Red, pbleft, pbtop, pbwidth, pbheight); // Draw red rectangle in your image.
g.Dispose();
pb.Image = im;

Maybe you want something like the following:

Graphics g = Graphics.FromImage(pb.Image); // Assume pb is your PictureBox
g.DrawRectangle(Pens.Red, pbleft, pbtop, pbwidth, pbheight); // Draw red rectangle in your image.
g.Dispose();

This will draw a red rectangle in your image. Is that what you want?

If compiling from command line ( csc ) use the switch /win32icon. If developing in Visual Studio, go to Project, Properties, the in the Application Tab where is says Icon.

Thank you for your reply. The ContextMenuStrip has a Size property and can be used to place the Context Menu above the point I want to use. Interestingly, the Size of the ContextMenuStrip is wrong the first time Show is called, so finally I used the method ContextMenuStrip.Show(PointToScreen(p, ToolStripDropDownDirection.AboveRight).

As has already been pointed out, this format string works with numeric types. Why don't you try?

double dAverageDensity = Double.Parse(strAverageDensity);
strAverageDensity = String.Format("{0:0.00}", dAverageDensity);

To calculate the centroid of a polygon: Source: http://en.wikipedia.org/wiki/Centroid[^] and http://local.wasp.uwa.edu.au/~pbourke/geometry/polyarea/[^]

PointF centroid(PointF[] p) {
// p is an array with the vertices of the polygon
float cx = 0;
float cy = 0;
float a = 0;
float ca;
for (int i = 0; i < p.Length; i++) {
ca = x[i] * y[(i + 1) % p.Length] - x[(i + 1) % p.Length] * y[i];
cx = cx + (x[i] + x[(i + 1) % p.Length]) * ca;
cy = cy + (y[i] + y[(i + 1) % p.Length]) * ca;
a = a + ca / 2;
}
cx = cx / (6 * a);
cy = cy / (6 * a);
return new PointF(cx , cy);
}

By the way, I am not sure if what you need is a centroid. Hope this helps, anyway.

Hi all, Using the Show() method of ContextMenu class ( in Windows.Forms ) it is possible to show a Context Menu. One of the arguments to the Show() method is the top left position of the Context Menu. What I know is, instead of the top left position, the bottom left position of the Context Menu. I would like to translate this somehow to the top left position, however, neither ContextMenu nor MenuItem seem to have a Height or Size property. Does anyone know how to fix the bottom left position of a Context Menu? Any help would be greatly appreciated. Thank you.

modified on Saturday, August 14, 2010 11:23 AM