How to populate a treeview from a dataset - C# Discussion Boards

Richard W Allen17-Oct-07 21:24

Richard W Allen

17-Oct-07 21:24

Patrick Sears wrote:
I just adorned my objects and their properties with the appropriate Xml attributes

Thanks, XMLSerialization is just what I need, but I don't understand the bit about attributes. Could you please provide more information, or tell me where I might find it?

Patrick Etc.18-Oct-07 8:07

Patrick Etc.

18-Oct-07 8:07

Sure!

The XmlSerializer by default will serialize an object's public properties and fields using the names in your object.

Say you have an object called Person, and it has a Name and a Gender.

public class Person
{
  private string mName;
  private string mGender;

  public string Name
  { 
    get;set;
  }

  public string Gender
  { 
    get;set;
  }
}

By default the XmlSerializer will create something that looks like this:

< Person>
   <Name>Whatever</Name>
   <Gender>Whatever</Gender>
</Person>

But you can adorn the object to change the way the object is serialized. For example, if you want it to be serialized as a "Human" and the Name and Gender properties to be XML attributes instead of XML elements:

[XmlType("Human")]
public class Person
{
  private string mName;
  private string mGender;

  [XmlAttribute("Name")]
  public string Name
  { 
    get;set;
  }

  [XmlAttribute("Gender")]
  public string Gender
  { 
    get;set;
  }
}

This will create XML that looks like this:

<Human Name="Whatever" Gender="Whatever" />

You can read more about the XmlSerializer and how to use it here:
http://msdn2.microsoft.com/en-us/library/system.xml.serialization.xmlserializer(vs.80).aspx[^]

and here:
http://msdn2.microsoft.com/en-us/library/ms950721.aspx[^]

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Richard W Allen18-Oct-07 8:52

Richard W Allen

18-Oct-07 8:52

All is now clear. Many thanks for your help

backgroundworker vs threading

Patrick Etc.18-Oct-07 9:51

Patrick Etc.

18-Oct-07 9:51

Glad I could help Smile | :)

brsecu16-Oct-07 9:41

brsecu

16-Oct-07 9:41

Whats the difference?

Re: backgroundworker vs threading

il_masacratore16-Oct-07 9:44

il_masacratore

16-Oct-07 9:44

Backgroundworker is an easy way to open a different thread in an higher level implementation to make an isolated operation. Theading requires sometimes more control about states, semaphors...

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Re: backgroundworker vs threading

Scott Dorman16-Oct-07 13:33

Scott Dorman

16-Oct-07 13:33

Ultimately there is no difference as both will allocate a thread from the thread pool. The BackgroundWorker component is a "visual" component (something that can be dropped on to a form at design time) that was created to help simplify creating a multi-threaded application.

Using the background worker is not ideal for all situations and using it doesn't mean you shouldn't have an understanding of how threading behaves.

Scott.

—In just two days, tomorrow will be yesterday.

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How to populate a treeview from a dataset

KirkNew2C#16-Oct-07 9:32

KirkNew2C#

16-Oct-07 9:32

I am very new to C#. I need to create a Windows form that will read a SQL table and populate a treeview. I can connect to the DB, create the dataadapter, populate a data set. The problem is how to use the dataset to populate a treeview.

I have looked at a few examples here but none use a dataset, or the data structure was different and I could not modify to work with my data or the examples were more than I needed and too complex for a beginner. Can some one suggest a URL, book or show me an example of code that simply takes the data as shown and populates a treeview.

I would really appreciate the help.

Thank you.

I have a SQL Server 2005 table containing this data shown below.

Child Parent depth Hierachy
1 NULL 0 01
2 1 1 01.02
5 2 2 01.02.05
6 2 2 01.02.06
3 1 1 01.03
7 3 2 01.03.07
11 7 3 01.03.07.11
14 11 4 01.03.07.11.14
12 7 3 01.03.07.12
13 7 3 01.03.07.13
8 3 2 01.03.08
9 3 2 01.03.09
4 1 1 01.04
10 4 2 01.04.10
15 NULL 0 15
15 15 1 15.15
16 15 1 15.16
18 16 2 15.16.18
17 15 1 15.17

Send/Receive commands w/PS2 keyboard

JayHart16-Oct-07 8:24

JayHart

16-Oct-07 8:24

I need to send various ps2 commands to my keyboard as part of my apps functionality.
Example from the PS2 spec:
0xF5 = disable kybd
0XF2 = Read ID

Some commands like the Read ID also require the ability to get the response.

I Googled for awhile so I turn here for some ideas.
Thanks,

JayHart

led mike16-Oct-07 8:38

led mike

16-Oct-07 8:38

PS2 as in Play Station? So your writing PS2 games using C#? Wow... I need to do some Googling! Good luck.

JayHart16-Oct-07 8:39

JayHart

16-Oct-07 8:39

Nope, not playstation,
the old cruudy keyboard you plug into your PC instead.

Jay

led mike16-Oct-07 8:59

led mike

16-Oct-07 8:59

I had a page fault

I have no experience using a keyboard for anything other than input.

Dan Neely16-Oct-07 9:41

Dan Neely

16-Oct-07 9:41

I don't believe you can send any output beyond the status of the num, scroll, and capslock keys to change the indicator lights. You'll need to read up on the hardware implementation to match what your device is expecting to see with what signals are generated when the states of those keys are altered on the PC.

--
If you view money as inherently evil, I view it as my duty to assist in making you more virtuous.

[Message Deleted]

Trustapple16-Oct-07 8:21

Trustapple

16-Oct-07 8:21

[Message Deleted]

Dave Kreskowiak16-Oct-07 8:29

Dave Kreskowiak

16-Oct-07 8:29

Oh God...

SERIOUSLY, you need to pick up a book on C# for beginners. The questions you've asked go back to the frist day of any beginning programming class.

A guide to posting questions on CodeProject[^]

Dave Kreskowiak
Microsoft MVP
Visual Developer - Visual Basic
2006, 2007

Anthony Mushrow16-Oct-07 9:46

Anthony Mushrow

16-Oct-07 9:46

Does sound like a set of questions you'd get near the beginning of a programming course...

My current favourite word is: Waffle

Cheese is still good though.

led mike16-Oct-07 8:36

led mike

16-Oct-07 8:36

Do I need to find J4amieC?

In case you didn't understand what Jamie said, you should STOP typing messages into forums and spend more time READING.

MasterSharp16-Oct-07 11:08

MasterSharp

16-Oct-07 11:08

You almost sound like me... Frown | :(

^);P

The most knowledge doesn't mean the most wise...

Help with SQL Parameter

kallileo16-Oct-07 8:08

kallileo

16-Oct-07 8:08

What am I doing wrong?

SqlConnection conn = new SqlConnection("Data Source=(local)\\SQLEXPRESS;Initial Catalog=opc;Integrated Security=True");
conn.Open();
SqlCommand selCmd = new SqlCommand("SELECT COUNT(*) FROM data WHERE timestamp>@pdate1 AND timestamp<@pdate2", conn);

SqlParameter date1 = new SqlParameter();
date1.ParameterName = @pdate1;
date1.Value = TextBox1.Text;
SqlParameter date2 = new SqlParameter();
date2.ParameterName = @pdate2;
date2.Value = TextBox2.Text;

selCmd.Parameters.Add(date1);
selCmd.Parameters.Add(date2);

int count = (int)selCmd.ExecuteScalar();
Label1.Text = count.ToString();
conn.Close();

I get 2 errors:
Error 1 The name 'pdate1' does not exist in the current context
Error 2 The name 'pdate2' does not exist in the current context

Giorgi Dalakishvili16-Oct-07 8:48

Giorgi Dalakishvili

16-Oct-07 8:48

It should look like this:
date1.ParameterName = "@pdate1";
date2.ParameterName = "@pdate2";

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kallileo16-Oct-07 9:07

kallileo

16-Oct-07 9:07

Yes I found it few minute later...Thanks

But now I get another error.

protected void Button_Click(object sender, EventArgs e)
{
SqlConnection conn = new SqlConnection("Data Source=(local)\\SQLEXPRESS;Initial Catalog=opc;Integrated Security=True");
conn.Open();
SqlCommand selCmd = new SqlCommand("SELECT COUNT(*) FROM data WHERE timestamp>@date1 AND timestamp<@date2", conn);
SqlParameter param1 = new SqlParameter();
SqlParameter param2 = new SqlParameter();
param1.ParameterName = "@date1";
param1.Value = TextBox1.Text;
selCmd.Parameters.Add(param1);

param2.ParameterName = "@date2";
param2.Value = TextBox2.Text;
selCmd.Parameters.Add(param2);

int count = (int)selCmd.ExecuteScalar();
Label1.Text = count.ToString();
conn.Close();

}
I get this Sql Exception:

Arithmetic overflow error converting expression to data type datetime.

In line "int count = (int)selCmd.ExecuteScalar();"

I need to count the rows between these two dates...

Giorgi Dalakishvili16-Oct-07 9:18

Giorgi Dalakishvili

16-Oct-07 9:18

It means that when date1 and date2 are replaced with values from the textbox they are not formated correctly and inside the query they can't be compared. Try running the query manually in sql server to see what error you will get. Also, if I remember it correctly, datetime variables need ' in the query

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kallileo16-Oct-07 9:32

kallileo

16-Oct-07 9:32

I tried the below query

SELECT COUNT(*) AS Expr1
FROM data
WHERE (timestamp > 19 / 08 / 2007) AND (timestamp < 23 / 08 / 2007)

manually but got 0

The column is

19/8/2007 10:25:40 am
19/8/2007 10:25:59 am
20/8/2007 6:10:56 am
20/8/2007 6:11:49 am
20/8/2007 6:20:20 am
20/8/2007 6:20:32 am
20/8/2007 6:20:38 am