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hi friends
How i can delete data from data base(sql server) in C#?????
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this is simple script to delete using webform asp.net C#
here is my code:
1. adding connection in Web.config
Web.config
==========
<connectionStrings>
<add name="myConnection" providerName="System.Data.SqlClient" connectionString="server=.\SQLEXPRESS;Initial Catalog=MyDB;Integrated Security=True"/>
</connectionStrings>
2. in default.aspx
default.aspx
============
added namespace:
using System.Data.SqlClient;
using System.Configuration;
protected void Page_Load(object sender, EventArgs e)
{
if (!IsPostBack)
{
string connProvider = ConfigurationManager.ConnectionStrings["myConnection"].ToString();
using (SqlConnection cnn = new SqlConnection(connProvider))
{
cnn.Open();
string userid = "1";
string query = "Delete Users Where UserID = '" + userid + "'";
using (SqlCommand cmd = new SqlCommand(query, cnn))
{
cmd.ExecuteNonQuery();
}
}
}
}
hope this help. (Update)= this code not recommended for develop, you can try it for learn and you can improve your code.
regard,
Ade Ruyani
modified 24-Dec-13 3:49am.
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Reason for my downvote: Do not concatenate strings to build a SQL command. It leaves you wide open to accidental or deliberate SQL Injection attack which can destroy your entire database. Use Parametrized queries instead. Even in a simple example like this, it takes hardly any extra work to do it properly!
Never underestimate the power of stupid things in large numbers
--- Serious Sam
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Thank you sam, this is just a simple code, whether they can improve they're code using store procedure or else.
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Ade.Ruyani.Z wrote: this is just a simple code It is still a bad example, because it leads to careless coding.
Veni, vidi, abiit domum
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int RowsAffected = 0;
using(SqlConnection cn = new SqlConnection(ConnectionStringHere))
{
cn.Open();
using(SqlCommand cmd = new SqlCommand())
{
cmd.Connection = cn;
cmd.CommandType = CommandType.Text;
cmd.CommandText = "Delete from tablename where id = @id";
cmd.Parameters.AddWithValue("@id",id);
RowsAffected = cmd.ExecuteNonQuery();
}
}
Every day, thousands of innocent plants are killed by vegetarians.
Help end the violence EAT BACON
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hi friends
How i can delete data from data base(sql server) in C#?????
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I am using Visual Studio 2010 with Sql server Express Edition 2005 as backend DB. I've a form with DataGridView with following columns:
OrderID
ProductID
UnitPrice
Quantity
Total
DataGridView is bind to Dataset Table, "Total" is a Calculated column which I've added using following code:
column = new DataColumn();
column.DataType = Type.GetType("System.Double");
column.ColumnName = "Total";
ds.Tables[0].Columns.Add(column);
ds.Tables[0].Columns["Total"].Expression = "UnitPrice * Quantity";
Code works fine, it calculate the Total by multiplying UnitPrice to Quantity. The problem is this calculation is made when I move to new row. What I need is to it calculate Total when there is any change in UnitPrice or Quantity.
Is it possible? Any ideas/Suggestions will be highly appreciated.
Regards
Ahmed
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Have you tried to update the values in the CellLeave event for your datagrid.
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No, can you give me some sample code please?
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after looking a little more, it may be better to use the cellvaluechanged event...
sample
(note this was tested only in C# win32.forms, and the column ValueTypes are strings):
private void dataGrid_CellValueChanged(object sender, DataGridViewCellEventArgs e) {
if ((e.RowIndex >= 0) && e.ColumnIndex != DataGrid.Columns["Total"].Index) {
int r = e.RowIndex;
int Qty = 0;
int.TryParse((string)DataGrid["Quantity", r].Value, out Qty);
double Price = 0D;
double.TryParse((string)DataGrid["UnitPrice", r].Value, out Price);
DataGrid["Total", r].Value = Price * Qty;
}
}
modified 24-Dec-13 19:07pm.
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This helps a lot....big thanks...
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Hello All,
I have an ASP.Net label error message set at the top of the page. And for some reason MaintainScrollPositionOnPostback = false is not working. I would like the page to scroll back to top, so users can see this error message. It does not scroll to the top, and maintains its existing position, leaving the user to keep clicking submit button.
I have tried this:
Specified on the code behind of asp.net user control:
Page.MaintainScrollPositionOnPostBack = false;
It does not scroll back to top of the page, as i would like it to so the user can read the message at the top of the page.
am I missing anything?
Thanks!
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Hi all
I just moved a entire solution from my laptop to a server where VS 2012 is installed. When I try to debug step by step, one of string is always empty. VS 2012 said that it doesn't exist on this context . This is a very simple code which try to retrieve value of app.config file:
string attributeWindowsLogin = ConfigurationManager.AppSettings["WindowsLogin"].ToString();
string attributeFullName = ConfigurationManager.AppSettings["FullName"].ToString();
string attributeAlpSid = ConfigurationManager.AppSettings["ALPSID"].ToString();
attributeFullName is always unknown by VS.
Impossible for me to edit a class.
Please what's wrong with my project ?
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Does the 'FullName' element exist in the config file?
Getting information off the Internet is like taking a drink from a fire hydrant.
- Mitchell Kapor
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Hi
of course this attribute exists. When I execute the code on Watch window, it works.
Maybe it is a problem with key of projrct. It is impossible to edit the class!
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Weird. I am using VS2013, but I also have VS2012 installed. I have never seen this issue before, though. Not sure what is causing it.
Getting information off the Internet is like taking a drink from a fire hydrant.
- Mitchell Kapor
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How to upload flat file data to Oracle DB using C#?
Daljit S. Gill
modified 26-Dec-13 5:44am.
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Hi,
I have written the below code to read a larege text (1.5 gb) using background worker thread. Also I have used StreamReader.ReadLine() method.
But I am receiving OutOfMemoryException(I have mentioned where I am receiving the exception in code as comments).
Is there any any way to read data from large text file?
const string dataFile = @"D:\\test.txt";
string line;
public Form1()
{
InitializeComponent();
InitializeBackgroundWorker();
}
private void InitializeBackgroundWorker()
{
backgroundWorker1.DoWork +=
new DoWorkEventHandler(backgroundWorker1_DoWork);
backgroundWorker1.RunWorkerCompleted +=
new RunWorkerCompletedEventHandler(
backgroundWorker1_RunWorkerCompleted);
backgroundWorker1.ProgressChanged +=
new ProgressChangedEventHandler(
backgroundWorker1_ProgressChanged_1);
}
private void button1_Click(object sender, EventArgs e)
{
backgroundWorker1.RunWorkerAsync();
}
private void backgroundWorker1_DoWork(object sender, DoWorkEventArgs e)
{
StringBuilder sb = new StringBuilder();
using (FileStream fs = File.Open(dataFile, FileMode.Open, FileAccess.Read, FileShare.ReadWrite))
using (BufferedStream bs = new BufferedStream(fs))
using (StreamReader sr = new StreamReader(bs))
{
while ((line = sr.ReadLine()) != null)
{
if (backgroundWorker1.CancellationPending)
{
e.Cancel = true;
break;
}
sb.AppendLine(line + "\n");
e.Result = sb;
}
}
}
private void backgroundWorker1_RunWorkerCompleted(object sender, RunWorkerCompletedEventArgs e)
{
if (e.Cancelled)
{
MessageBox.Show("You've cancelled the backgroundworker!");
}
else
{
richTextBox1.AppendText(e.Result.ToString());
MessageBox.Show("Done");
}
}
private void backgroundWorker1_ProgressChanged(object sender, ProgressChangedEventArgs e)
{
progressBar1.Value = e.ProgressPercentage;
}
private void backgroundWorker1_ProgressChanged_1(object sender, ProgressChangedEventArgs e)
{
}
private void button2_Click(object sender, EventArgs e)
{
backgroundWorker1.CancelAsync();
}
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To respond meaningfully to your query, I think we need to know more about the context:
0. structure of the file ? flat ? cvs ? JSON, XML, compressed ?
1. reading from ... where ? a local drive, a network server, the web ?
2. hardware: how much ram do you, or your app's users' machines, have ?
3. use case: is it absolutely necessary to read the whole file, or, can you read it in chunks, and process/transform it chunk-by-chunk ? see: >[^] for an example of reading by chunks.
4. compression: is the file compressible in a way you could that there could be significant memory savings if you could compress the file first, load the compressed file into memory, and then operate on the compressed file as needed ... within the requirements of whatever you are doing with the file content, and the acceptable response times for operations on/with the file ?
“I'm an artist: it's self evident that word implies looking for something all the time without ever finding it in full. It is the opposite of saying : 'I know all about it. I've already found it.'
As far as I'm concerned, the word means: 'I am looking. I am hunting for it. I am deeply involved.'”
Vincent Van Gogh
modified 23-Dec-13 7:02am.
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0. structure of the file ? flat ? cvs ? JSON, XML, compressed ?
flat file
1. reading from ... where ? a local drive, a network server, the web ?
local drive
2. hardware: how much ram do you, or your app's users' machines, have ?
2gb ram
3. use case: is it absolutely necessary to read the whole file, or, can you read it in chunks, and process/transform it chunk-by-chunk ? see: >[^] for an example of reading by chunks.
Even if I read it in chunks it not an issue.But I have to read the file.
In my text file, I will have data like
12/12/2013 John 23/12/1978
New York USA 1234-567-897
What I am trying to say is,my data will span over two different lines to form one complete data.
4. compression: is the file compressible in a way you could that there could be significant memory savings if you could compress the file first, load the compressed file into memory, and then operate on the compressed file as needed ... within the requirements of whatever you are doing with the file content, and the acceptable response times for operations on/with the file ?
If you compress it can you read the data?
BR,
Arjun
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