C# Discussion Boards - CodeProject

1-Dec-06 4:46

How can I prevent items from an outside location from being accepted as drops? I'm making a dialog to move items between two listboxes, and need to keep external strings from being dropped into either.

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Rules of thumb should not be taken for the whole hand.

ed^nrgc1-Dec-06 5:27

ed^nrgc

1-Dec-06 5:27

Do checks in the OnDragOver event.

Dan Neely1-Dec-06 5:42

1-Dec-06 5:42

Where am I supposed to get the data to identify the source from? sender is the potential recipient, and DragEventArgs doesn't have a member indicating the souce.

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Rules of thumb should not be taken for the whole hand.

Dave Kreskowiak1-Dec-06 5:40

Dave Kreskowiak

1-Dec-06 5:40

Encapsulate your strings in a custom IDataObject impementation. When you check for the correct data type in your DragOver and DragDrop events, you just look for data of that custom type. If it's not there, well, you know you're getting data from an unauthorized source.

Dave Kreskowiak
Microsoft MVP - Visual Basic

Dan Neely1-Dec-06 5:42

1-Dec-06 5:42

Thank you. Smile | :)

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Rules of thumb should not be taken for the whole hand.

Dan Neely1-Dec-06 8:09

1-Dec-06 8:09

It appears I don't need to implement a custom IDataObject, just a custom type to put into the stock DataObject that gets passed around. Much less work this way.

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Rules of thumb should not be taken for the whole hand.

Dave Kreskowiak1-Dec-06 8:17

Dave Kreskowiak

1-Dec-06 8:17

Whatever works! I just thought of it off the top of my head. I never said I did it myself! Big Grin | :-D

Dave Kreskowiak
Microsoft MVP - Visual Basic

Dan Neely1-Dec-06 8:21

what is this used for --> @

1-Dec-06 8:21

No worry, without your idea, I'd've probably spent more time searching for what I ended up doing than I lost starting to implement the innerface.

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Rules of thumb should not be taken for the whole hand.

Making dates

digsy_1-Dec-06 4:36

digsy_

1-Dec-06 4:36

I have a web page where the user selects a month and year and submits it to the system.

I then need to create two dates - the first and last dates of that month - which are then sent to another page.

Whats the best way to do this ? I came up with the idea of subtracting the month from todays month, doing the same with the year and then creating the start date.

But this involves converting a string -> int -> date and then back to string - which seems like a lot of converting.

Re: Making dates

Guffa1-Dec-06 4:56

Guffa

1-Dec-06 4:56

Use the DateTime.DaysInMonth to get the number of days in the month. Then you can easily create DateTime structures from the values, and format the dates as you like them.

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Re: Making dates

Pete O'Hanlon1-Dec-06 4:59

Pete O'Hanlon

1-Dec-06 4:59

This looks suspiciously homeworky Big Grin | :-D

. Anyway, here's the easy way to do it:

// To get the start date.
DateTime startDate = new DateTime(selectedYear, selectedMonth, 1, 0, 0, 0, 0);
// Add 1 month to get the start of next month, and then subtract 1 day.
DateTime endDate = startDate.AddMonths(1).AddDays(-1);

You can use a similar trick to get the first and last days from any date:

// Set to the 26th November 2006
DateTime dt = new DateTime(2006, 11, 26,0,0,0,0);
// Gets the 1st November
DateTime startDate = dt.AddDays((-(dt.Day)) + 1);
// Gets the 30th November
DateTime endDate = startDate.AddMonths(1).AddDays(-1);

Arthur Dent - "That would explain it. All my life I've had this strange feeling that there's something big and sinister going on in the world."
Slartibartfast - "No. That's perfectly normal paranoia. Everybody in the universe gets that."

Deja View - the feeling that you've seen this post before.

karanba1-Dec-06 4:34

karanba

1-Dec-06 4:34

In some codes I saw @ character before string. I here that it is used in php sytax for breaking loops, but could not found any clue what it does in c#

karanba

eggsovereasy1-Dec-06 4:44

eggsovereasy

1-Dec-06 4:44

Makes it so escape characters are skipped.

string x = "What now man? \nWe are going to the store";
Console.WriteLine(x);

will output:

What now man?
We are going to the store

whereas this:

string x = @"What now man? \nWe are going to the store";
Console.WriteLine(x);

will output:

What now man? \nWe are going to the store

karanba1-Dec-06 4:57

karanba

1-Dec-06 4:57

thaks much.

karanba

Guffa1-Dec-06 5:00

Guffa

1-Dec-06 5:00

A @ delimited string has the double quote as only escape code.

These declarations are equivalent:

string a = "A string with \"quotes\" and a backslash: \\ in it.";
string b = @"A string with ""quotes"" and a backslash: \ in it.";

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