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You must add DataColumn objects to a table before you bind to them. Also you have another error which will not be catched by any compiler. Make meaningful names! Col_1 and Col_2 tells nothing!
I would do it like this:
DataTable table = new DataTable();
table.Columns.Add("Name", typeof(string));
table.Columns.Add("Text", typeof(string));
DataRowView dr;
for (int i = 0; i < 10; i++) {
dr = table.DefaultView.AddNew();
dr["Name"] = "Name " + i.ToString();
dr["Text"] = "Some text no. " + i.ToString();
}
table.AcceptChanges();
Greetings - Gajatko
Portable.NET is part of DotGNU, a project to build a complete Free Software replacement for .NET - a system that truly belongs to the developers.
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Is the "double" type is faster than "float" type in .Net when using them in loops?
I sensed in my experience that it is true. somebody has any idea about it?
and why it must be true?
thank you
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small_programmer wrote: Is the "double" type is faster than "float" type in .Net when using them in loops?
I sensed in my experience that it is true. somebody has any idea about it?
and why it must be true?
double and float have different precisions. Performance is not something I've ever taken into consideration when deciding to use one over the other.
I'm guessing that if you've seen double as being faster it is probably because the processor's native floating point representation is a double and float s (although they save memory) will be slower as a result because the processor converts them internally to double s, processes it then converts it back. But, that is just my guess.
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Thank you
I think you are right.
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Colin Angus Mackay wrote: I'm guessing that if you've seen double as being faster it is probably because the processor's native floating point representation is a double and floats (although they save memory) will be slower as a result because the processor converts them internally to doubles, processes it then converts it back. But, that is just my guess.
That would be to line up on the word boundaries, I've always thought.
"Try asking what you want to know, rather than asking a question whose answer you know." - Christian Graus
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Hi Paul,
I am sure it is not related to memory alignment: double alignment is not
more relaxed than float alignment. If there is any difference in performance, one
should have a look at actual code (assembly rather than MSIL); it could prove
Colin's guess is right.
Luc Pattyn [Forum Guidelines] [My Articles]
this weeks tips:
- make Visual display line numbers: Tools/Options/TextEditor/...
- show exceptions with ToString() to see all information
- before you ask a question here, search CodeProject, then Google
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Hmmm, I think I might just write up a quick little app to do a fun little weekend investigation
"Try asking what you want to know, rather than asking a question whose answer you know." - Christian Graus
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Hi Paul,
any interesting results in your float/double perfo investigation?
Luc Pattyn [Forum Guidelines] [My Articles]
this weeks tips:
- make Visual display line numbers: Tools/Options/TextEditor/...
- show exceptions with ToString() to see all information
- before you ask a question here, search CodeProject, then Google
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Nothing really outstanding at this point. Seems to be a push between the two.
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Colin Angus Mackay wrote: I'm guessing that if you've seen double as being faster it is probably because the processor's native floating point representation is a double and floats (although they save memory) will be slower as a result because the processor converts them internally to doubles, processes it then converts it back. But, that is just my guess.
It's correct that the processor does all operations internally using doubles. Which ever type is faster also depends on several other factors, though. If you for example process an array of numbers, floats may be faster than doubles just because more of them fits in the processor cache.
---
single minded; short sighted; long gone;
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Hi
for floating point operations Double is the most efficient type because those operations are optimized by hardware.
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thank you all.
look at these codes
1.
for(int i=0;i<100000000;i++)
{
float f1=i/357;
float f2=i/546;
if(f1>f2/3454)
{
f2=f1;
}
}
2.
for(int i=0;i<100000000;i++)
{
double f1=i/357;
double f2=i/546;
if(f1>f2/3454)
{
f2=f1;
}
}
the first code consume 7.27 sec and second code consume 6.73 sec in my computer.
of course assignment statement is high time consumer.
somebody has any idea about it?
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Is it possible to send xml data contains folder information from windows service to web application , if it is possible please help me
thanks in advance
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I have a user-defined control which has as a child control a TextBox (.NET 3.0). When I call Focus() on this TextBox, it doesn't work. However, if I add a MessageBox.Show() line, and then call Focus(), it does indeed Focus on the TextBox. I'm not sure what is happening here - focusing on a different control, and then on the TextBox, doesn't seem to produce the same effect. Can anybody point out my (probably obvious) mistake?
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Try to call Focus() on the user control first. Where did you add the MessageBox.Show() line?
Greetings - Gajatko
Portable.NET is part of DotGNU, a project to build a complete Free Software replacement for .NET - a system that truly belongs to the developers.
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The code is like this:
<br />
LineControl newLineControl = GetControlForLine(newLine);<br />
MessageBox.Show("try now"); <br />
newLineControl.Dialogue.Focus();
I tried adding newLineControl.Focus() before newLineControl.Dialogue.Focus() as suggested, but it didn't make a difference.
I tried logging when each control gets and loses focus, and got the following result when clicking on a LineControl (my user control):
TextBox got focus
LineControl got focus
..then away from it:
TextBox lost focus
LineControl lost focus
This was the same regardless of whether the MessageBox.Show() line was included, yet when that line is included, newLineControl.Dialogue.Focus() works, and when it isn't, it doesn't. Any ideas? Very confused.
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Hi All,
I want to save the data in the textboxes of a form, in an excel sheet programmatically.
I know it to do using datagridview....but i dont get any idea as to how to transfer the data in textboxes to the excel sheet.
Please Help Me.
Regards,
Priya
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What part do you not have any idea with? Is it the datagridview part or the Excel Office Interop part ( I am assuming this is how you are going to do it )?
"Any sort of work in VB6 is bound to provide several WTF moments." - Christian Graus
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sir,
i want to make an 'exe' in visual studio 2005.
Which offers a connection to another 'exe'(running or installed in windows).How to make a connection like that
which gives a link to another programme.just as AJAX extensions making connection with visual studio 2005.
If anybody have the answer pleaes reply me
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You are not very clear. If you want to run another .exe from an .exe, you can use the Process class.
"Any sort of work in VB6 is bound to provide several WTF moments." - Christian Graus
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Hey Guys
1. I wanna know how to Monitor internet speed and connection state in C#, i m working of Windows Based Application (Related with SQL Server Database). In this Application i also wanna add some Add-Ins, I created 5 Add-ins for it so far. This Internet monitor will be the one of them.
2. SQL Server has 3 States
A. Running
B. Stop
C. Paused
How can i control these States from C# Remotely..?
Thanks
It will be apprehended..
I have No idea at all
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code for reading .dwg file from folder through specifing the path where the files are saved and opening those files in a seperate window and the data contained in those files should be read and write that data into an excel file in simple way we need to select the files though browse folder dialog box in c# and i need the coding or program gor that plz help me
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I think that you can find some useful resources here.
Greetings - Gajatko
Portable.NET is part of DotGNU, a project to build a complete Free Software replacement for .NET - a system that truly belongs to the developers.
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code for reading data from .DWG file and write to an excel file
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I want to execute commands in remote system (using IP)at cmd.exe using hyper terminal or telnet in c#.net windows application.
terminal or console should not be visible. It should receieve the commands and execute on the selected system are return the result.
Please suggest me to this
Praveenkumar Palla
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