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I am trying to load data from a data file. At first I declared a list called list<client> clients and I was able to load this list.
Then I tried to declare a class list as shown below and the program crashed on the add statement. Could someone please explain:
namespace WindowsApplication2
{
public struct client
{
public string matter;
public string name;
}
public class clientList
{
public List<client> data;
}
static class Program
{
[STAThread]
static void Main()
{
client Myclient;
clientList clients = new clientList();
FileStream aFile = new FileStream
("TextFile1.txt", FileMode.Open);
StreamReader sr = new StreamReader(aFile);
//load data into the Myclient list
Myclient.matter = sr.ReadLine();
while(Myclient.matter!=null)
{
Myclient.name = sr.ReadLine();
clients.data.Add(Myclient);
Myclient.matter = sr.ReadLine();
}
//
Application.EnableVisualStyles();
Application.SetCompatibleTextRenderingDefault(false);
Form1 f = new Form1();
Application.Run(f);
}
}
}
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it looks like the clientList class needs a constructor that initializes data.
data = new List < client > ();
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Thank you, I will try that. My main program invokes a form (Form1) and Form1 invokes another form Form2.
How can I load my list in the main function and make it available to these forms?
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the best way depends on your programs structure and how you're going to use the data. two methods would be to make the list a static global so anybody can access it or pass the list to your forms as a parameter during construction. Again, it depends on how your program is structured but I'd generally prefer parameter passing to globals.
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Jerry Graham wrote: public class clientList
{
public List<client> data;
}
You have to "new" the internal list before you can use it. You make a new ClientList class but, the internal List is not created when you do. I suggest either A) Hiding the list internally (after you new it of course) you shouldn't expose members like that, or B) doing away with the containing class if it only has a List in it.
Scott P
"Run for your life from any man who tells you that money is evil. That sentence is the leper's bell of an approaching looter." --Ayn Rand
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Thanks! I placed the list in a class because,my main program invokes a form (Form1) and Form1 invokes another form Form2 and I want to load my list and make it available (globally) to these forms?
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You can pass the list around just like you pass a class around.
Scott P
"Run for your life from any man who tells you that money is evil. That sentence is the leper's bell of an approaching looter." --Ayn Rand
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Hi All,
i used this code:
protected void btnAddToCart_Click(object sender, ImageClickEventArgs e)
{
string Price = double.Parse(((Label)DataList1.Controls[0].FindControl("PriceLabel")).Text);
}
but now i have this error: double:Cannot implicity convert type double to string.
why this error occured?
what do i do now?
thank you
Hoda
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You don't need to use double.Parse(), just assign the string variable to the text outcome of the control
Mohamed El Gohary
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string Price = double.Parse(((Label)DataList1.Controls[0].FindControl("PriceLabel")).Text).ToString("0.00");
I Love T-SQL
Don't torture yourself,let the life to do it for you.
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Saba02 wrote: why this error occured?
because
1) double.Parse(...) returns a double
2) string Price = expects a string
Saba02 wrote: what do i do now?
get your act together.
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Saba02,
Two things. You are assigning a string with a double. And you should also use TryParse();
Label priceLabel = DataList1.Controls[0].FindControl("PriceLabel") as Label;
double price = double.TryParse(priceLabel.Text);
Regards,
Gareth.
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gareth111 wrote: double price = double.TryParse(priceLabel.Text);
your intentions are good, your syntax isn't.
The documentation tells differently.
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Hi Gareth,
no problem!
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Hi!
I am using MS Visio control in an application developed in C# (for .Net 1.1). I have a class MyAppContext that extends ApplicationContext. The application is started by calling Application.Run(myAppContext) where myAppContext is an instance of class MyAppContext.
The problem I face, is this, only under Vista, if a form containing Visio control is initialized, a NullRefrenceException is thrown. However, if I load the same form before initializing myAppContext, it works fine.
The same code works under XP and Windows 2003. I have also used 'Run as Administrator' option in Vista but the result is same.
Does anyone have a clue, what should I do to fix this problem?
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Kashif Iqbal Khan wrote: a NullRefrenceException is thrown
by whom? at what line? catch the exception, look at its ToString() output, tell
Visual Studio to always show line numbers, and identify the faulty line.
A wild guess: you did something that is not thread-safe, your XP machine is single core
so it runs fine nevertheless, and your Vista machine is dual core, so it is bound to fail.
As I said, this is just a guess.
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Thanks for your prompt reply.
The exception stack trace shows that it is thrown somewhere in AxHost class. Unfortunately, I am not at my work place right now, so cannot attach the exact StackTrace. But will update as soon as I get it.
To explain further, I am writing the code flow that is something like as follows
<br />
<br />
VisioForm f = new VisioForm();<br />
f.Show();<br />
f.Close();<br />
<br />
MyApplicationContext c = new MyApplicationContext; <br />
Application.Run( c );<br />
<br />
<br />
There is a button on MainForm that has the same code as mentioned in Line 1-3 above in its click event. Now If I comment the code as in Line 1-3, the application will crash if the button on main form is clicked. But works fine, if I leave it there.
More interestingly, If the lines 1-3 are moved between line 4 and 5, the application will still crash with the same message.
This makes me believe that there is something wrong when using ActiveX controls inside a custom application context on Vista.
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Hi,
I have some remarks, not sure how relevant they are:
1. are you sure about your f.Show f.Close sequence? it shows then hides the form, without
waiting for anything? or did you mean ShowDialog()?
2. I would put everything in one big try-catch as in:
try {
... all about VisioForm
... all about MyApplicationContext
} catch(Exception exc) {
Console.WriteLine(exc.ToString());
}
that will catch everything in the main thread that you may have forgotten to catch
elsewhere. Note the ToString, it is important to see the entire exception.
3.
Are you manipulating apartment models? is everything STAThread? MTAThread?
Maybe the Visio stuff needs it to be STAThread. I don't know the details, I do know
it often is an issue when using COM.
4.
Are you using the same version of Visio on both machines?
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Thanks for all your effort.
1. Yes, it is form.Show() and form.Close(). This is actually a work around to make the application work on Vista. After placing these lines, VisioForm opens fine whenever the button on MainForm is clicked.
2. The code does has try-catch. Problem is I cannot get my form open. I will put the exception log here.
3. Main module has STA Attribute.
4. Yes.
Actually if I open and close the form containing Visio control (Line 1-3 in my previous post), before application context initialization, my application works fine on Vista. but If I remove these lines, it starts crashing whenever the VisioForm is initialized.
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Hi Guys. I have an opendiledialoge. If I click Cancel then the whole project closses. Any idea how I can set it to return to the main form if the user clicks on cancel instead of having the whole app closing??
Here is the code.
if (openFileDialog1.ShowDialog() != DialogResult.OK)
{
this.Close();
}
Excellence is doing ordinary things extraordinarily well.
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I have solved it.
I set it as follows:
if (openFileDialog1.ShowDialog() != DialogResult.OK)
{
return;
}
Excellence is doing ordinary things extraordinarily well.
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Ah, that was a good laugh.
"I told my app to close, and it closes; but I don't want it to close, how do I get it not to close? (Help urgent please)" 
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He figured it out and fixed it. Obviously not a Hlp Urgnt Pls at all, just a beginner. Just like you and I were
Jon
Smith & Wesson: The original point and click interface
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