problem ado.net application

[mo/-/sin]

hi. i m mohsin
i m making a gui application using c# at front end and sql server 2005
at backend...... i made a table in sql server 2005 with 4 columns and
in gui i used 4 text boxes and 4labels and three buttons. my full code
is mentioned below....... button1 is for add button2 is for save and
button3 is for delete...
the table is empty..but the lines prefix with ---- are giving
errors............ plz tel me why............ i also used a binding
navigator and bind all the columns correctly.............

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;
using System.Data.SqlClient;

namespace CITY_HOSPITAL
{

public partial class Form20 : Form
{
DataTable dt;
DataRow dr;
string code;
public Form20()
{
InitializeComponent();

}

private void textBox3_TextChanged(object sender, EventArgs e)
{

}

private void Form20_Load(object sender, EventArgs e)
{
// TODO: This line of code loads data into the
'cITY_HOSPITALDataSet.SERVICESMAINTENANCE' table. You can move, or
remove it, as needed.

this.sERVICESMAINTENANCETableAdapter.Fill(this.cIT Y_HOSPITALDataSet.SERVICESMAINTENANCE);
textBox1.Enabled = false;
textBox2.Enabled = false;
textBox3.Enabled = false;
textBox4.Enabled = false;
button2.Enabled = false;
}

private void button1_Click(object sender, EventArgs e)
{
button2.Enabled = true;
textBox2.Enabled = true;
textBox3.Enabled = true;
textBox4.Enabled = true;
textBox2.Text = "";
textBox3.Text = "";
textBox4.Text = "";
int ctr, len;
string codeval;
dt = cITY_HOSPITALDataSet.Tables["SERVICESMAINTENANCE"];
----- len = dt.Rows.Count - 1;
---- dr = dt.Rows[len];
code = dr["SERVICEID"].ToString();
codeval = code.Substring(1, 5);
ctr = Convert.ToInt32(codeval);
if ((ctr >= 1) && (ctr < 9))
{
ctr = ctr + 1;
textBox1.Text = "SER00" + ctr;
}
else if ((ctr >= 9) && (ctr < 99))
{
ctr = ctr + 1;
textBox1.Text = "SER0" + ctr;
}
else if (ctr >= 99)
{
ctr = ctr + 1;
textBox1.Text = "SER" + ctr;
}
button1.Enabled = false;
}

private void button2_Click(object sender, EventArgs e)
{
dt = cITY_HOSPITALDataSet.Tables["SERVICESMAINTENANCE"];
dr = dt.NewRow();
dr[0] = textBox1.Text;
dr[1] = textBox2.Text;
dr[2] = textBox3.Text;
dr[3] = textBox3.Text;
dt.Rows.Add(dr);

sERVICESMAINTENANCETableAdapter.Update(cITY_HOSPIT ALDataSet);
textBox2.Text = System.Convert.ToString(dr[0]);
textBox1.Enabled = false;
textBox2.Enabled = false;
textBox3.Enabled = false;
textBox4.Enabled = false;

this.sERVICESMAINTENANCETableAdapter.Fill(this.cIT Y_HOSPITALDataSet.SERVICESMAINTENANCE);
button1.Enabled = true;
button2.Enabled = false;
}

private void button3_Click(object sender, EventArgs e)
{
string code;
code = textBox1.Text;
if (textBox1.Text.Length == 0)
{
MessageBox.Show("PLEASE SELECT A VALID RECORD");
}
else
{
dr =
cITY_HOSPITALDataSet.Tables["SERVICESMAINTENANCE"].Rows.Find(code);
dr.Delete();

sERVICESMAINTENANCETableAdapter.Update(cITY_HOSPIT ALDataSet);
}

}

}

}

[Marc Gravell]

but the lines prefix with ---- are giving errors

What errors? (please copy the exact error message)

The code you posted gives an idea, but we can't use that "as is" to
investigate anything. But if you give us the error message we might be
able to help.

Can I guess "NullReferenceException", "Object reference not set to an
instance of an object."?

In which case either the table isn't called "SERVICESMAINTENANCE"
inside the DataSet (just enumerate the .Tables to see what *is*
there), or you haven't loaded it correctly. Try using the table as:
dt = cITY_HOSPITALDataSet.SERVICE*SMAINTENANCE;

Or simply check that your DataSet is not completely empty.

Marc

[mo/-/sin]

On Aug 19, 12:59*pm, Marc Gravell <[e-mail]:

but the lines prefix with ---- are giving errors

What errors? (please copy the exact error message)

The code you posted gives an idea, but we can't use that "as is" to
investigate anything. But if you give us the error message we might be
able to help.

Can I guess "NullReferenceException", "Object reference not set to an
instance of an object."?

In which case either the table isn't called "SERVICESMAINTENANCE"
inside the DataSet (just enumerate the .Tables to see what *is*
there), or you haven't loaded it correctly. Try using the table as:
dt = cITY_HOSPITALDataSet.SERVICE*SMAINTENANCE;

Or simply check that your DataSet is not completely empty.

Marc

ok buddy.......
the error is "there is no row at position -1" however if i change to 0
or +1 the error is there is no row at position 0 or +1 respectively....

[mo/-/sin]

On Aug 19, 6:14*pm, "mo/-/sin" <[e-mail]:

On Aug 19, 12:59*pm, Marc Gravell <[e-mail]:

but the lines prefix with ---- are giving errors

What errors? (please copy the exact error message)

The code you posted gives an idea, but we can't use that "as is" to
investigate anything. But if you give us the error message we might be
able to help.

Can I guess "NullReferenceException", "Object reference not set to an
instance of an object."?

In which case either the table isn't called "SERVICESMAINTENANCE"
inside the DataSet (just enumerate the .Tables to see what *is*
there), or you haven't loaded it correctly. Try using the table as:
dt = cITY_HOSPITALDataSet.SERVICE*SMAINTENANCE;

Or simply check that your DataSet is not completely empty.

Marc

ok buddy.......
the error is"INDEXOUTOFRANGEEXCEPTION" below this it is written that
"there is no row at position -1" however if i change to 0
or +1 the error is there is no row at position 0 or +1 respectively...

[mo/-/sin]

On Aug 19, 6:23*pm, "mo/-/sin" <[e-mail]:

On Aug 19, 6:14*pm, "mo/-/sin" <[e-mail]:

On Aug 19, 12:59*pm, Marc Gravell <[e-mail]:

but the lines prefix with ---- are giving errors

What errors? (please copy the exact error message)

The code you posted gives an idea, but we can't use that "as is" to
investigate anything. But if you give us the error message we might be
able to help.

Can I guess "NullReferenceException", "Object reference not set to an
instance of an object."?

In which case either the table isn't called "SERVICESMAINTENANCE"
inside the DataSet (just enumerate the .Tables to see what *is*
there), or you haven't loaded it correctly. Try using the table as:
dt = cITY_HOSPITALDataSet.SERVICE*SMAINTENANCE;

Or simply check that your DataSet is not completely empty.

Marc

ok buddy.......
the error is"INDEXOUTOFRANGEEXCEPTION" below this it is written that
"there is no row at position -1" however if i change to 0
or +1 the error is there is no row at position 0 or +1 respectively...

as per your suggestion i insert two rows directly into that table
using sql server 2005... but now the error is in the line " ctr =
Convert.ToInt32(codeval); " and the error is formatexception was
unhandled and below that it is written that INPUT STRING WAS NOT IN A
CORRECT FORMAT'.............

[Marc Gravell]

OK, so the original error was that there weren't any rows and you
weren't checking for this...

The second error; what is a typical "codeval" value when you debug it?

Marc

[mo/-/sin]

On Aug 19, 7:40*pm, Marc Gravell <[e-mail]:

OK, so the original error was that there weren't any rows and you
weren't checking for this...

The second error; what is a typical "codeval" value when you debug it?

Marc

as i told u there are three buttons in my application and when i debug
that application i m not able see the application instead of that i
see this error.............

[Marc Gravell]

as i told u there are three buttons in my application and when i debug

that application *i m not able see the application instead of that i
see this error.............

There are lots of ways of getting a value if the debugger isn't happy
- write the value to the console, the trace, the event log or just a
flat file if you need to! You're going to have to know what it thinks
that value is to debug it.

Marc