Re: Listboxes ... finding certain numbers - C# Discussion Boards

2-Mar-08 14:32

Here is the format:

$75 3/2/2008

How do I find just the second and third character? The 75 ?

Anthony Mushrow2-Mar-08 14:40

Anthony Mushrow

2-Mar-08 14:40

Well, the simplest, and least flexible way is to get the second and third characters out of the string, perhaps like this:

string sNumber = listboxitem.SubString(1,2);
//You may also want the value of your number
int iNumber;
Int32.TryParse(sNumber, ref iNumber);

I might have got the params for TryParse wrong, but thats the easiest way to do it.

Of course if the number went to 3 digits it wouldn't get the whole number.

My current favourite word is: Nipple!

-SK Genius

Jacob Dixon2-Mar-08 14:47

2-Mar-08 14:47

for (int z = 0; z < PaidToDateListbox.Items.Count; z++)
{
    int count = 0;
    string thenumber = PaidToDateListbox.Items[z].ToString();
    int length = thenumber.Length - 3;
    thenumber.Remove(3, length);
    thenumber.Remove(0, 1);
    count = count + Convert.ToInt32(thenumber);
}

This is what I had and I get this error:

Input string was not in correct format.

Luc Pattyn2-Mar-08 15:20

Luc Pattyn

2-Mar-08 15:20

Hi,

1.
string.Remove() does not modify the string, it returns a new string, so you should
write thenumber=thenumber.Remove(3, length); etc.
That is because strings are immutable, nothing in .NET can modify them.

2.
If you are only interested in part of a string, string.Substring() is the method you want,
hence thenumber=thenumber.Substring(1, 2); holds the second and third char.

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aj.esler2-Mar-08 14:49

aj.esler

2-Mar-08 14:49

Are you trying to just show the 2nd and 3rd characters in the list box, or get the 2nd and 3rd chars of the selected text in the list box?
If the latter, try the following:

<br />
string selectedText = listBox1.SelectedItem.ToString();<br />
textBox1.Text = selectedText.Substring(1,2);<br />
<br />
// OR<br />
<br />
char[] selectedTextChars = listBox1.SelectedItem.ToString().ToCharArray();<br />
textBox1.Text = selectedTextChars[1].ToString() + selectedTextChars[2].ToString();<br />

There could well be a better ways though. This way will give you problems if the format changes, or it goes to three digits.
Hope that helps...

Jacob Dixon2-Mar-08 14:54

2-Mar-08 14:54

It is a list box that my wife will enter an amount that the parents paid for daycare.. She will enter the amount next to the date in the list box like this: $75 3/2/2008

Then what I want to do is I have a text box below it that will add the amount (money) together and give a total amount. So I have to extract the second and third character (number) and convert it to a integer.

This was when there are multiple ones I can add them together.

How to load Kernel32.dll and use GetSystemInfo(...)

dipak.dipak2-Mar-08 19:25

dipak.dipak

2-Mar-08 19:25

Hello, This is an example :

int intTotal = 0;
for (int i = 0; i < DropDownList1.Items.Count; i++)
{
intTotal += Convert.ToInt16(DropDownList1.Items[i].Text.Substring(1, 2));
}

It is OK.
I have tested it.
Best of Luck.

Dipak

gshen2-Mar-08 12:59

gshen

2-Mar-08 12:59

Dear Friends:
I am using c# Interop/(Platform Invoke) to call Win32 function GetSystemInfo(...). My computer is Windows XP profession Service Pack 2. The declaration is as follows:
[DllImport("Kernel32.lib")]
static extern void GetSystemInfo(ref SYSTEM_INFO systInfo);

The Kernel32.dll is located in C:\WINDOWS\ServicePackFiles\i386. The original location might be in C:\WINDOWS\system32. I set the environmental variable Path = C:\WINDOWS\ServicePackFiles\i386. When I run my program, the error message says "Unable to load DLL 'Kernel32.lib': The specified module could not be found. (Exception from HRESULT: 0x8007007E)". I then copied the Kernel32.dll to C:\WINDOWS\system32. The same error message popped out. I then copied Kernel32.dll to my prgram's subdirectory. The same message came out. I can use other Win32 functions without problem, such as NetWkstaGetInfo(..l) in Netapi32.dll. Anybody can help? I appreciate your kind help.

Sheng

Re: How to load Kernel32.dll and use GetSystemInfo(...)

Anthony Mushrow2-Mar-08 14:14

Anthony Mushrow

2-Mar-08 14:14

Its because your asking for Kernel32.lib rather than Kernel32.dll
Simple as that. I think.

My current favourite word is: Nipple!

-SK Genius

Re: How to load Kernel32.dll and use GetSystemInfo(...)

Luc Pattyn2-Mar-08 15:22

Luc Pattyn

2-Mar-08 15:22

Yep, SKGenius is right, a lib is not a dll.
And you should not worry too much about where the dll is, Windows typically will
find the standard dll's for you without you giving a path.

Smile | :)

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Opening multiple files

Jacob Dixon2-Mar-08 10:16

2-Mar-08 10:16

Source: mscorlib
Inner Exception:
Target: Void FileNotOpen()
Message: Cannot access a closed file.

I keep getting this error and can not figure it out.. I am actually opening a certain file and writing to it, then opening another one then writing to it and so on. Should I not be doing this? Is this causing maybe them not opening in time before it tries to write to them?

FileStream ChildFile = new FileStream(thepath + @"Child\Child.daycare", FileMode.Create);
StreamWriter Childsw = new StreamWriter(ChildFile);
                    Childsw.WriteLine(fullnameTextbox.Text);
                    Childsw.WriteLine(birthTextbox.Text);
                    Childsw.WriteLine(startTextbox.Text);
                    ChildFile.Close();
                    Childsw.Close();
                   
FileStream GuardianFile = new FileStream(thepath + @"Guardian\ParentGuardian.daycare", FileMode.Create);
StreamWriter Guardiansw = new StreamWriter(GuardianFile);
                    Guardiansw.WriteLine(guardNameTextbox.Text);
                    Guardiansw.WriteLine(relationTextbox.Text);
                    Guardiansw.WriteLine(textBox1.Text);
                    Guardiansw.WriteLine(CityStateZipTextbox.Text);
                    Guardiansw.WriteLine(EmployTextbox.Text);
                    Guardiansw.WriteLine(Guard2Textbox.Text);
                    Guardiansw.WriteLine(Relation2Textbox.Text);
                    Guardiansw.WriteLine(Address2Textbox.Text);
                    Guardiansw.WriteLine(CityStateZip2Textbox.Text);
                    Guardiansw.WriteLine(Employ2Textbox.Text);
                    GuardianFile.Close();
                    Guardiansw.Close();

There are more.. but should I be doing this a different way?

Giorgi Dalakishvili2-Mar-08 10:22

Giorgi Dalakishvili

2-Mar-08 10:22

When you create one stream from another you should first close the newly created one and then the base one. So this snippet

FileStream ChildFile = new FileStream(thepath + @"Child\Child.daycare", FileMode.Create);
StreamWriter Childsw = new StreamWriter(ChildFile);
Childsw.WriteLine(fullnameTextbox.Text);
Childsw.WriteLine(birthTextbox.Text);
Childsw.WriteLine(startTextbox.Text);
ChildFile.Close();
Childsw.Close();

should be like this:

FileStream ChildFile = new FileStream(thepath + @"Child\Child.daycare", FileMode.Create);
StreamWriter Childsw = new StreamWriter(ChildFile);
Childsw.WriteLine(fullnameTextbox.Text);
Childsw.WriteLine(birthTextbox.Text);
Childsw.WriteLine(startTextbox.Text);
Childsw.Close();
ChildFile.Close();

Also, use using block with streams so that they will be closed and disposed automatically

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Jacob Dixon2-Mar-08 10:24

2-Mar-08 10:24

Ok I will try that and see if it works.. I was wondering if I should have included something that waited till it was open to start writing but I do not know how to do that and my book doesn't say anything about that.. let me try that and I will be right back.. thanks for the fast response

Jacob Dixon2-Mar-08 10:28

2-Mar-08 10:28

Awesome that worked.. thanks so much.. why would that affect it though?

Giorgi Dalakishvili2-Mar-08 10:50

Giorgi Dalakishvili

2-Mar-08 10:50

Glad to help you Smile | :)

When you tried to close the second stream, the base stream was already closed so that was causing a problem.

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