In windows form, if you don't want user to close the form by pressing Alt+F4 or Cross (x) button accidently and without saving existing form status, you may need to capture the form close event.

In the FormClosing event of form, FormClosingEventArg has a property called CloseReason. This is very usefull because if you want the Form to stop closing if the closing reason was CloseReason.UserClosing or some thing else.

You can do e.Cancel = true to prevent form being closed, then do something in your code and finally close the form programatically.

e.g.

        private void Form1_FormClosing(object sender, FormClosingEventArgs e)
        {
                e.Cancel = true;

                //Check the status of form, Save form status if required or other logic

                this.Close();
        }

In windows form, if you have richtextbox or multiline textbox then usually enter key use to enter a new line.

But if AcceptButton property of Form is set for some action/button press, then pressing enter key in richtextbox or multiline textbox doesn't enter a new line rather AcceptButton calls.

To supress this set the property AcceptsTab to true in richtexbox. In case of multiline textbox / control set AcceptsReturn and AcceptTab property to true.

Tonight in windows form, using C# language I required to use key combination like we use Ctrl+S to save form, CTRL+F to find etc.

In windows form, its quite easy. Just enable KeyPreview property to true. This property makes the form get the key events before the controls, so you can set the KeyPress event on the form.

Form1.KeyPreview = true;

After that, set the form event for the keypress/key down

this.KeyDown += new KeyEventHandler(this.Form1_KeyDown);

Now shortcut part comes here, follow like this

private void Form1_KeyDown(object sender, KeyEventArgs e)
{
 if (Control.ModifierKeys == Keys.Control && e.KeyCode == Keys.S)
 {  
  //SaveData();
 }
 else if (Control.ModifierKeys == Keys.Control && e.KeyCode == Keys.F)
 {  
  //Find();
 }
}

Hope it helps some one.

Today I need to convert between string and hexadecimal in C#...

         public string StrToHex(string plainText)
        {
            char[] charArray = plainText.ToCharArray();
            StringBuilder sb = new StringBuilder();
            int num;
            string hex;
            for (int i = 0; i < charArray.Length; i++)
            {
                if (i > 0)
                {
                    sb.Append("-");
                }
                num = Convert.ToInt32(charArray[i]);
                hex = num.ToString("x");
                sb.Append(hex);
            }
             return sb.ToString();
        }

 ===========

         public string HexToStr(string hexaText)
        {
           string[] strArray = hexaText.Split(new char[] { '-' });
            StringBuilder sb = new StringBuilder();
            for (int i = 0; i < strArray.Length; ++i)
            {
                sb.Append((char)Convert.ToInt32(strArray[i], 16));
            }
            return sb.ToString();
        }

 ============ 

Implementation as

string str = "TestString";
string hexStr = StrToHex(str);   // => 54-65-73-74-53-74-72-69-6e-67
str = HexToStr(hexStr); // => TestString

Sample Code Oracle stored procedure - In this simple implementation, call commit at the end of work done, and Rollback if any exception occur.

PROCEDURE SAVE_TWO_THINGS(
IN_THING_ONE IN VARCHAR2,
IN_THING_TWO IN VARCHAR2)
IS

BEGIN

INSERT INTO TABLEONE
(ACTIVE, THING_DESC)
VALUES
('Y', IN_THING_ONE);


INSERT INTO TABLETWO
(ACTIVE, THING_DESC)
VALUES
('N', IN_THING_TWO);

COMMIT;

EXCEPTION WHEN OTHERS THEN 
ROLLBACK;
END;

Today I need to implement transaction in .NET. Front end language was VB.NET and database was Oracle.

This transaction is being implemented using Oracle Data Access Provider - ODP.NET.

Simple implementation is that create and open a connection, begin transaction using that connection, create command using that connection, call stored procedures or statments using command(s), if every thing gone fine and success then call commit of that transaction else rollback, and in last close and dispose connection and transaction.

Be sure not to use commit, rollback or statement that causes transaction invalidate inside the procedure that is being called within .NET transaction, otherwise that .NET transaction scope will no longer valid as within that connection commit or rollback have been called.

Sample code that make my work done is :-

=============

Private Sub Save()
Dim conn As New OracleConnection("ConnString")
Dim trans As OracleTransaction
Dim success as Boolean = False

Try
conn.Open()
 trans = conn.BeginTransaction
success =  saveThingOne(conn)
If success Then
success = saveThingTwo(conn)
End If

If success  Then
 trans.Commit()
else
trans.Rollback()
End If

Catch ex As Exception
 trans.Rollback()
Finally
trans.Dispose()
conn.Close()
conn.Dispose()
End Try
End Sub