make databound checkbox checked in C#.net2005 winform application

normal checkbox can use checkbox1.checked = true;

databound checkbox needs to change the checkstate: checkbox1.checkstate = checkstate.checked;

make databound checkbox checked in C#.net2005 winform application

normal checkbox can use checkbox1.checked = true;

databound checkbox needs to change the checkstate: checkbox1.checkstate = checkstate.checked;

check whether form is already opened in C#.net 2k5 winform application

created the form object in application settings

Code to open the form:
private void button1_Click(object sender, EventArgs e) {

if ( Properties.Settings.Default.frmReg == null )
{
Properties.Settings.Default.frmReg = new frmRegistration();
Properties.Settings.Default.frmReg.Show( this );
}
else if ( Properties.Settings.Default.frmReg != null && Properties.Settings.Default.frmReg.WindowState ==

FormWindowState.Minimized)
{
Properties.Settings.Default.frmReg.WindowState = FormWindowState.Normal ;
}
else
{
Properties.Settings.Default.frmReg.Focus();
}
}

Code to close the opened form:
Properties.Settings.Default.frmReg = null;

something wrong with goggle?

what's happening with blogger.com? the whole weekend and this monday morning, sometimes can't create a new post, sometimes changes to the template are not reflected, come on!!!!!

check whether form is already opened in C#.net 2k5 winform application

created the form object in application settings

Code to open the form:
private void button1_Click(object sender, EventArgs e) {

if ( Properties.Settings.Default.frmReg == null )
{
Properties.Settings.Default.frmReg = new frmRegistration();
Properties.Settings.Default.frmReg.Show( this );
}
else if ( Properties.Settings.Default.frmReg != null && Properties.Settings.Default.frmReg.WindowState == FormWindowState.Minimized)
{
Properties.Settings.Default.frmReg.WindowState = FormWindowState.Normal ;
}
else
{
Properties.Settings.Default.frmReg.Focus();
}
}

Code to close the opened form:
Properties.Settings.Default.frmReg = null;

testing post

testing post

using OleDbCommand class to update a database table based on one or more variable values C#.net 2005 winform app

using ( OleDbConnection connection = new OleDbConnection( Properties.Settings.Default.HPMConnectionString ) )
{
connection.Open();
OleDbCommand changeActiveToNoCommand = new OleDbCommand( "UPDATE staff SET active = no WHERE staff_id = @staff_id" , connection );
changeActiveToNoCommand.Parameters.AddWithValue( "@staff_id" , Convert.ToInt64( staff_id ) );
changeActiveToNoCommand.ExecuteNonQuery();
}

using OleDbDataReader class to retrieve a value based on one or more variable values C#.net 2005 winform app

string staff_no = staffDataGridView.CurrentRow.Cells[0].Value.ToString();

string staff_id="";

using (OleDbConnection connection = new OleDbConnection(Properties.Settings.Default.HPMConnectionString))
{
//OleDbCommand findStaffIDCommand = new OleDbCommand("SELECT staff_id FROM staff WHERE staff_no = '" + staff_no + "'", connection);
OleDbCommand findStaffIDCommand = new OleDbCommand( "SELECT staff_id FROM staff WHERE staff_no = @staff_no",connection );
findStaffIDCommand.Parameters.AddWithValue( "@staff_no" , staff_no );

connection.Open();
OleDbDataReader reader = findStaffIDCommand.ExecuteReader();

while (reader.Read())
{
staff_id = (reader[0].ToString());
}
reader.Close();
}
MessageBox.Show( staff_id.ToString() );

dataGridView show value of any cell on selected row (multiRow select = false) C#.net 2005

MessageBox.Show(clientsDataGridView.CurrentRow.Cells[0].Value + "");

tooltip in VS2005 winform and asp applications

in winform applications, there is a component called "tooltip", which can be referenced by other visual components

in asp.net applications, there is a property called "tooltip" for most of the visual components, which can be used to enter single line tooltipss.
There is a third party tooltip utility called "cooltip", which is much more powerful:
http://www.acooltip.com/index.html#

make combobox readonly in C#.net 2005 winform application

change the value of property "DropDownStyle" to "DropDownList)

referencing other classes C#.NET 2005

if you create a class within a subfolder of a winform project, you can't reference it within he code of a class in the root folder of project.
Solution:
to create the class in the same folder/rootlevel as the class that needs to have referencing code, and then move the class into anyother folder

access application settings in code C#.NET 2005

to access the values predefined in application settings, do this:
label1.Text = Properties.Settings.Default.aaa;
aaa is the name of the variable;

to persist the change, do this:
Properties.Settings.Default.aaa = "bbb";
Properties.Settings.Default.Save();

i am back

it's been a while.....
busy doing my masters and working at the same time. have to submit a report next monday, another one is coming soon.

feel lost.....

force number input in .NET

This built-in function can be used to force user to input numbers:

if (!char.IsNumber(e.KeyPress))
messagebox.show("plz enter numbers only")

also, "decimal.tryparse" can be used to check if the input is a number after input

my babies

some of them are alomost 2 months old, majority are 3 wks or 1 wks old, happy begging for food all the time, never enough~

They energize my study and work as well as relax me when I am tired:)

Fibonacci Sequence number calculation (int16)

this chunk of code calculates Fibonacci Sequence number base on user input using C#.NET:

private void btnGetNumber_Click(object sender, EventArgs e)
{
try
{
if (txtInput.Text == "" txtInput.Text == null) //to avoid empty input
{
MessageBox.Show("Please input a positive Integer between 0 and 62", "Error: Empty Input", MessageBoxButtons.OK, MessageBoxIcon.Warning);
txtInput.Clear();
txtInput.Focus();
}
else
{
int theNum = Convert.ToInt16(txtInput.Text);
if (theNum == 0) //to avoid zero input
{ MessageBox.Show("Please input a positive Integer between 0 and 62", "Error: Zero Input", MessageBoxButtons.OK, MessageBoxIcon.Warning);
txtInput.Clear();
txtInput.Focus();
}
else if (theNum <> 46) //to avoid overflow result, if the variables are defined for bigger values, this condition should be commented out and use OverflowException
{
MessageBox.Show("Please input a positive Integer between 0 and 62", "Error: Result Overflew", MessageBoxButtons.OK, MessageBoxIcon.Error);
txtInput.Clear();
txtInput.Focus();
}
else //all conditions met, calculate the result
{
int numA = 0; int numB = 1; int numC;
for (int i = 1; i <= theNum; i++)
{
numC = numA;
numA = numB;
numB = numC + numB;
}
//print result to screen
lblAnswer.Text = numA.ToString();
} } }
//uncomment the code below for catching overflow exception when the variables are
//defined as uint64 or ulong, that is, too big to guess the limit
//catch (OverflowException)
//{
// MessageBox.Show("Please try again with another smaller positive Integer", "Error: Result OverFlow", MessageBoxButtons.OK, MessageBoxIcon.Error);
// txtInput.Clear();
// txtInput.Focus();
//}
//throw error for string or decimal inputs
catch (FormatException)
{
MessageBox.Show("Please input a positive Integer between 0 and 62", "Error: String or decimal Input", MessageBoxButtons.OK, MessageBoxIcon.Error);
txtInput.Clear();
txtInput.Focus();
}
//throw error for unknown errors
catch (Exception ee) { MessageBox.Show("Error: Unknown", ee.Message); Application.Exit(); } }

validate positive integer from user input

uint holds only positive numbers, this event checks if the input is a validate positive integer, otherwise throw error using C#.NET

private void button1_Click(object sender, EventArgs e)

{

uint value = 0;

if (!uint.TryParse(textBox1.Text, out value) value == 0)

{MessageBox.Show("Wrong format");

return;}

textBox2.Text = value.ToString();

}

PHP sample login code

just done a sample, hope its helpful for newbies like me
Click here to download phploginsample.rar. Don't forget to create a db called news_users, with 3 columns "username" (varchar/char, PK), "passwd" (varchar/char), and "access_level"(smallint, 0 or 1).

lesson learnt from PHP Parse error

silly word wrap, some environment doesnt support automatically word wrap when copy and paste code. so the solution is:

put "//" in front of every line of comment to prevent the error caused by a multiline comment led by only have "//" in front of first line.

copy-pasters be aware!