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how can Read/write directly to a specific sector in a hard disk
with c#
Please help me if anybody know
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Hi
I Saw this sample but it doesnt tell how can i write in sector, this sample just show total size of sector in disk
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It shows how to read from the disk, so it should not be too difficult to figure out from that how to write to it.
Veni, vidi, abiit domum
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rd.Read();
if (rd["allwid"].ToString() == "")
{
allwdet.Allowanceid = 1;
rd.Close();
}
else
{
allwdet.Allowanceid = int.Parse(rd["allwid"].ToString()) + 1;
rd.Close();
}
}
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One doesn't modify generated code; if something is wrong, you'd fix it in the model you're generating from.
As for the output; I'd imagine the first record to not have a value for it's allwid-column, and values 12 and 13 for records 2 and 3. What was your expected result? And what are the actual values in the database?
Offtopic; It'd be nice if the subject-line of your post contained the subject - not a complete question. That goes in the post itself.
Bastard Programmer from Hell 
If you can't read my code, try converting it here[^]
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Troubleshooting the query might help find solve the problem.
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what is the concept of teamviewer??
Can anyone just tell me what is the concept behind teamviewer???
I just need a simple concept to start....
Please someone help me in it...
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The first page of a google search lead me to this[^] blog page.
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I have a database that houses (amongst other things) data on defects and repairs, car repairs as an example. The way this db breaks down is this:
Table Defect holds the information about the defect (Damaged bumper, broken windshield, w/e)
Table Material holds information about materials used to repair (ex: new bumper)
Table Equipment holds information about equipment used to repair (ex: buffer)
Table Trade holds information about who is responsible for the repair and their wage (ex: mechanic)
There are three many to many tables that join defect with trade/eq/mat and have a quantity.
Long story short, I have a Scalar value UDF that returns the value of all of these costs together divided by a value in the defect table.
I decided to try to simplify it into a query (The simplification discussion is a TSQL issue outside the scope of this post) and in doing so had to ask myself, does this belong as a SQL query or should I write it as an additional property of the model in c#?
I could just as easily write a partial class that handles all of this craziness on the web server side. Is this all pedantic? Is it really a question of db server performance vs web server performance? I have read that scalar value functions in TSQL can be low performing due to threading issues, which is what sparked this thing in the first place.
Thoughts? Opinions?
Cheers, --EA
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eddieangel wrote: Is it really a question of db server performance vs web server performance?
Probably. If it is in fact a 'better' application if this specific feature is 'faster' and the speed up is achieved by one or the other (probably via TSQL) then that would be the deciding factor.
Other than that it is conceptually business logic but given the complexity of the data entities then I would suspect that it is less complex (lower maintenance) to leave it in the database.
eddieangel wrote: I have read that scalar value functions in TSQL can be low performing
Which sounds irrelevant without information about the requirements, architecture, design and measured performance of the application (not benchmarks) related to this.
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Thank you. You are right, "low performing" is immeasurable in the scope of my application. Because of the complexity of using a UDF with Entity Framework I am going to move the calculation to the web server side for the time being.
Cheers, --EA
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I would be asking myself where you are consuming the result, if it is ONLY in your UI then doing the calc in the model is valid. If however you intend to use it in reports then the database should be used.
You may also consider storing the result somewhere if it is used in reports. Recalcing it every time you run a report may not be the best option.
Never underestimate the power of human stupidity
RAH
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The question of storing the calculated field has been on my mind actually. In theory the calculation could happen one time (Only when the record is changed) and then stored. Otherwise it happens 1500 times (The number of records roughly) every time someone needs to access the data.
I think you are right that recalcing is not the best option, in spite of the fact that it has been done that way for a long time.
Thanks for the input, going to move it DB side, the amount of extra storage (1 field, 1500 to 3000 records) is negligible compared to the processing benefits.
Cheers, --EA
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Hi,
From my experience SQL is extremely powerful on data manipulation, and if I understood it right that what you doing here...
I see no reason (maybe conformance  ) to do it in C#, not even in a hosted CLR...
I'm not questioning your powers of observation; I'm merely remarking upon the paradox of asking a masked man who he is (V).
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Find out here[^]
=========================================================
I'm an optoholic - my glass is always half full of vodka.
=========================================================
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It's one place you can go to learn about programming.
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Maybe you need to start with a book on the basics of OOPS programming.
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"Class," and "Object," as used in modern computer science, both can have a wide range of meanings.
Assuming your goal is to understand these concepts in .NET, and C#, I'd suggest you download the free e-book by Charles Petzold, ".NET Book Zero," here: [^], and read Chapter 13, "Classes, Structures, and Objects," and then read Chapters 14, 15.
Both "Class" and "Object" can be regarded as basic concepts in the knowledge domain of "Object Oriented Programming."
Both terms can be regarded as reflecting the idea of a discrete "entity," a unit of logic, a semantic abstraction which models a "thing," or, "process," in the "real world."
I think reading about the history of Object Oriented Programming will help you get a sense of what these terms mean, and how they are often used quite differently by different people: [^].
On a practical level in .NET, a Class is a block of code which can be seen as a template, or factory, for the manufacture of instances of the Class; some would say that the instances of a Class are Objects, but the Class is not quite the same thing. Some would say that a Class is an Object, and there have been (and are) computer languages in which everything you can think of is considered to be a Class.
In .NET a Class is a provider of a "bundle" of functionality: a constructor that supports parameters, an ability to inherit structure from other Classes and Interfaces, ability to inherit data in other Classes. But, there are "Static" Classes in .NET, which behave quite differently, and you should experiment with those to understand how they are different from "regular Classes."
Google CEO, Erich Schmidt: "I keep asking for a product called Serendipity. This product would have access to everything ever written or recorded, know everything the user ever worked on and saved to his or her personal hard drive, and know a whole lot about the user's tastes, friends and predilections." 2004, USA Today interview
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i have a datatable with 3 columns Class, Student details, School Name
DataTable dt = new DataTable();
dt.Columns.Add("Class", typeof(System.String));
dt.Columns.Add("Student Details", typeof(System.String));
dt.Columns.Add("School Name", typeof(System.String));
dt.Rows.Add("12", "binod 16 Maths","X");
dt.Rows.Add("12", "Alex 17 History", "Y");
dt.Rows.Add("12", "Sam 18 Biology", "Z");
I want to convert this datatable into this below new datatable where i have splitted the "Student Deatils" column into 3 columns and added the values of this column separted by space in new columsn
dtNew.Columns.Add("Class", typeof(System.String));
dtNew.Columns.Add("Name", typeof(System.String));
dtNew.Columns.Add("Age", typeof(System.String));
dtNew.Columns.Add("Subject", typeof(System.String));
dtNew.Columns.Add("School Name", typeof(System.String));
Class Name Age Subject School Name
12 binod 16 maths X
12 Alex 17 History Y
12 Sam 18 Biology Z
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You have got the general idea right.
Are you facing some issue?
The Copy[^] method might give you some ideas well.
This thread[^] might be useful to you as well.
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Try
System.Data.DataTable dt = new DataTable();
dt.Columns.Add("Class", typeof(System.String));
dt.Columns.Add("Student Details", typeof(System.String));
dt.Columns.Add("School Name", typeof(System.String));
dt.Rows.Add("12", "binod 16 Maths", "X");
dt.Rows.Add("12", "Alex 17 History", "Y");
dt.Rows.Add("12", "Sam 18 Biology", "Z");
DataTable dtNew = new DataTable();
dtNew.Columns.Add("Class", typeof(System.String));
dtNew.Columns.Add("Name", typeof(System.String));
dtNew.Columns.Add("Age", typeof(System.String));
dtNew.Columns.Add("Subject", typeof(System.String));
dtNew.Columns.Add("School Name", typeof(System.String));
foreach (DataRow r in dt.Rows)
{
string details = (string)r[1];
string[] row = details.Split(' ');
dtNew.Rows.Add(r[0], row[0], row[1], row[2], r[2]);
}
foreach (DataRow r in dtNew.Rows)
{
Console.WriteLine(r[0] + " " + r[1] + " " + r[2] + " " + r[3] + " " + r[4]);
}
Console.ReadKey();
I don't speak Idiot - please talk slowly and clearly
"I have sexdaily. I mean dyslexia. Fcuk!"
Driven to the arms of Heineken by the wife
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ihave problem when print datagridview
this coding me
public partial class Form1 : Form
{
PrintDocument dokprint = new PrintDocument();
String koneksidatabase = " Provider=Microsoft.ACE.OLEDB.12.0;Data Source=C:\\DatabaseMDB\\DBSALES.mdb";
public Form1()
{
InitializeComponent();
printDocument1.PrintPage += printDocument1_PrintPage;
----------------------------------------------------------------------------------
private void button2_Click(object sender, EventArgs e)
{
if (TXTBAYAR.Text == "")
{
MessageBox.Show("Please insert Buy");
return;
}
for (int i = 0; i < dataGridView2.Rows.Count; i++)
{
OleDbConnection con = new OleDbConnection(koneksidatabase);
OleDbCommand cmd = new OleDbCommand("insert into Sales ([Kode],[Nama Barang],[Harga],[Quantity],[Satuan],[Subtotal]) values (@Column1,@Column2,@Column3,@Column4,@Column5,@Column6)", con);
cmd.Parameters.AddWithValue("@Kode", dataGridView2.Rows[i].Cells[0].Value);
cmd.Parameters.AddWithValue("@Column2", dataGridView2.Rows[i].Cells[1].Value);
cmd.Parameters.AddWithValue("@Column3", dataGridView2.Rows[i].Cells[2].Value);
cmd.Parameters.AddWithValue("@Column4", dataGridView2.Rows[i].Cells[3].Value);
cmd.Parameters.AddWithValue("@Column5", dataGridView2.Rows[i].Cells[4].Value);
cmd.Parameters.AddWithValue("@Column6", dataGridView2.Rows[i].Cells[5].Value);
OleDbConnection con1 = new OleDbConnection(koneksidatabase);
OleDbCommand cmd1 = new OleDbCommand("insert into DetailSales ([Kode],[Nama Barang],[Harga],[Quantity],[Satuan],[Subtotal],[Total],[Bayar],[Kembalian],[DateTime]) values (@Column1,@Column2,@Column3,@Column4,@Column5,@Column6,@Total,@Bayar,@Kembalian,@DateTime)", con);
cmd1.Parameters.AddWithValue("@Kode", dataGridView2.Rows[i].Cells[0].Value);
cmd1.Parameters.AddWithValue("@Column2", dataGridView2.Rows[i].Cells[1].Value);
cmd1.Parameters.AddWithValue("@Column3", dataGridView2.Rows[i].Cells[2].Value);
cmd1.Parameters.AddWithValue("@Column4", dataGridView2.Rows[i].Cells[3].Value);
cmd1.Parameters.AddWithValue("@Column5", dataGridView2.Rows[i].Cells[4].Value);
cmd1.Parameters.AddWithValue("@Column6", dataGridView2.Rows[i].Cells[5].Value);
cmd1.Parameters.AddWithValue("@Total", txttotal1.Text);
cmd1.Parameters.AddWithValue("@Bayar", TXTBAYAR.Text);
cmd1.Parameters.AddWithValue("@Kembalian", TXTKEMBALIAN.Text);
cmd1.Parameters.AddWithValue("@DateTime", labelJam.Text);
con1.Open();
con.Open();
cmd.ExecuteNonQuery();
cmd1.ExecuteNonQuery();
con.Close();
con1.Close();
}
{
{
printDocument1.Print();(---this error)
dataGridView2.Rows.Clear();
MessageBox.Show("TRANSACTION COMPLITE!", "Complite");
TXTBAYAR.Clear();
TXTTOTAL.Clear();
TXTKEMBALIAN.Clear();
}
}
}
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Looks like you have an issue connecting to the printer.
Look at the error and try to figure out the problem.
Post the error here.
As a side note, add a try catch block to your code to handle the error.
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