|
I don't need to store the data - actually, the downloaded bytes should just be deleted afterwards.
Thought about doing something like this:
reader.ReadBytes(1000); reader.Position = (file.Length - 1000); reader.ReadBytes(1000);
Would that work? And what is the file is smaller than 1000kb?
|
|
|
|
|
If the stream is seekable, you're pretty close.
I think, if the stream is smaller than 2000 Kb you should read the entire file? Else you would copy duplicate data and (if the file is less than 1000 Kb) cause an exception.
|
|
|
|
|
i added a report viewer control to my project and selected 2 columns from database table..now i want to add my own custom column in report.hw can i do that?
|
|
|
|
|
Hello guys.
I would like to know how to extract the mathematical
expression from a string and compute the result.
Sample: The user will type 5 + 2 - 3 * 4 which will be in a string format.
Then the result will be assigned to a double variable.
Also, the user can include parenthesis in the expression: 5 + (3 / 9)
Thanks a lot.
|
|
|
|
|
In fact you can have a simple to a more complete solution...
Parsing grammar is based on definitions, for instance BNF, ABNF...
In your case, you can write a simple peace of code in order to have your expression parsed.
But if you want to have a more complexe handling use this pointer and check the section 7.2
[^]
Please update us.
|
|
|
|
|
One approach is to put the expression in a binary tree with numbers (or variables) at the leaves and operators at the interior nodes. Replace higher-precedence operators (and parenthesized expressions) with subtrees first.
To evaluate, do a postorder traversal, applying the operator at each interior node to the values obtained from its two subtrees.
When you're done, the result will be in the root node.
|
|
|
|
|
Hmmm... looks like a teacher assigned an RPN assignment yesterday.
See my response here[^].
|
|
|
|
|
I think without explicity declaring the order of precedence of operator execution ... i.e. : is this infix, postfix, RPN ? ... you cannot begin to respond to this question.
There are some math expression "parser" articles around CodeProject; try this one : [^].
best, Bill
"Many : not conversant with mathematical studies, imagine that because it [the Analytical Engine] is to give results in numerical notation, its processes must consequently be arithmetical, numerical, rather than algebraical and analytical. This is an error. The engine can arrange and combine numerical quantities as if they were letters or any other general symbols; and it fact it might bring out its results in algebraical notation, were provisions made accordingly." Ada, Countess Lovelace, 1844
|
|
|
|
|
Hello.
I have a DataGridView with 3 Columns and 100000 Rows.
If I select all rows and press "Del" keys from keyboard,
then it takes too long to delete all of them.
Are there anyways to improve the performance ?
Thanks.
|
|
|
|
|
The grid is updating, and repainting. A lot 
You can temporarily disable drawing using the SuspendLayout[^] method, and turn it back on using ResumeLayout.
I are Troll 
|
|
|
|
|
In fact the suspend layout will not help on this issue.
You must use a virtual mode in order to avoid such redraw issue.
Look at this all is in....
[^]
|
|
|
|
|
Migounette wrote: In fact the suspend layout will not help on this issue.
I had to check to verify that, and it seems that you are right.
+5
I are Troll
|
|
|
|
|
Perhaps setting the datasource to null and deleting the actual data on a background thread would help?
Alternatively, why put 100,000 rows in a datagrid, nobody will scroll through them all, so filter before load?
Bob
Ashfield Consultants Ltd
Proud to be a 2009 Code Project MVP
|
|
|
|
|
i was tring to write some data to the parallel port using inpout32.dll but i keep getting this exception
SEHException was unhandled:
External component has thrown an exception
this is the code i used
class PortAccess
{
[DllImport("inpout32.dll", EntryPoint = "Out32")]
public static extern void Output(int adress, int value);
}
public void OUT()
{
PortAccess.Output(888, 1);
}
am i doing something wrong or wat?
|
|
|
|
|
It may be several problems, but it appears to be an issue with the access of the library or the port.
Which OS are you running ?
More over add this to your main app in order to get the information, please update us.
[STAThread]
static void Main(string[] cmdLine)
{
try
{
Application.ThreadException += ApplicationThreadException;
Application.SetUnhandledExceptionMode(UnhandledExceptionMode.CatchException);
...
}
catch (Exception exception)
{
...
}
finally
{
...
}
}
|
|
|
|
|
tnx 4 ur reply..
I am using WindowsXp SP2. and i posted only some part of the code, it is a windows form application on visiual studio 2008.
i called the PortAccess.output function on a button click event. every thing works fine until i click the button
|
|
|
|
|
did you try to add the global exception catch and dump its message
|
|
|
|
|
thanks but i got the solution. i download the updated INPOUT32.dll from http://www.logix4u.com and it worked
|
|
|
|
|
pls provide the same DLL to me...
|
|
|
|
|
THE SEHException is really nasty to debug. Because it comes from the COM.
I was able to resolve this nasty bug only by uninstalling .NET 3.5 SP1 and reinstalling again. Because I use windows 7 I had to do this from my windows add/remove components section.
Others suggestions like reseting IIS failed.
VJ Koganti
http://www.PrintersRose.com/
|
|
|
|
|
Hi all...
I'm asking of how i can encrypt and decript a txt file using C#,
i think u don't mined to help me ...
Thank u...............
|
|
|
|
|
|
because you want both Encrypting and Decrypting I would offer you gunzipstream
public string Decode()
{
FileStream fs = new FileStream(Environment.GetFolderPath(Environment.SpecialFolder.MyDocuments) + "\\MyFile.dat", FileMode.Open, FileAccess.ReadWrite);
byte[] array = new byte[400];
GZipStream gstream = new GZipStream(fs, CompressionMode.Decompress);
gstream.Read(array, 0, array.Length);
gstream.Close();
string Mytext = Encoding.UTF8.GetString(array);
return Mytext;
}
public void Encode(string text)
{
byte[] array = Encoding.UTF8.GetBytes(text);
FileStream fs = new FileStream(Environment.GetFolderPath(Environment.SpecialFolder.MyDocuments) + "\\MyFile.dat", FileMode.Create, FileAccess.ReadWrite);
GZipStream gstream = new GZipStream(fs, CompressionMode.Compress);
gstream.Write(array, 0, array.Length);
gstream.Flush();
gstream.Close();
}
note: this solution is not completely secure!
|
|
|
|
|
Hi,
How could you make this happen on the click of a button? I've tried adding it to the event but the Public void Encode(string text) line obviously stops this happening.
edit: Some of my terminology may not be correct, so if your unsure, just ask.
modified on Monday, December 21, 2009 10:41 AM
|
|
|
|
|
just insert button on the form and double click it, Then
write button1_Click event code like shown.
In this sample I encoded text of TextBox1 to 'Myfile.dat' in My Document
note: must copy Encode function to Form class
private void button1_Click(object sender, EventArgs e)
{
Encode(TextBox1.Text);
}
public void Encode(string text)
{
byte[] array = Encoding.UTF8.GetBytes(text);
FileStream fs = new FileStream(Environment.GetFolderPath(Environment.SpecialFolder.MyDocuments) + "\\MyFile.dat", FileMode.Create, FileAccess.ReadWrite);
GZipStream gstream = new GZipStream(fs, CompressionMode.Compress);
gstream.Write(array, 0, array.Length);
gstream.Flush();
gstream.Close();
}
modified on Thursday, December 24, 2009 10:23 AM
|
|
|
|
General 
News 
Suggestion 
Question 
Bug 
Answer 
Joke 
Praise 
Rant 
Admin 
Submit an article or tip
