Datasets and Web Services - C# Discussion Boards

I'd like to use the column like the header column in DataGrid

20-Feb-05 16:29

There's a 3rd part component on my form that keeps turning my arrow cursor into a wait cursor. Is there a way to stop this?

uh, i'm pretty sure it's the 3rd party component...

/\ |_ E X E GG

yu-yu20-Feb-05 14:41

yu-yu

20-Feb-05 14:41

I'd like to use the column like the header column in DataGrid.
If I do it, I can the following action.

I create 4 columns. I set 2nd column for header column.
If I scroll the table, 1st and 2nd column fixed. And
3rd and 4th column moved.

please tell me some ideas.

regards,
yu-yu

Datasets and Web Services

ronin177020-Feb-05 14:01

ronin1770

20-Feb-05 14:01

HI,

I am trying to build a simple web services which simply get list of employee's last name from Sql server's database. The method in web-service class is supposed to read the data from the db and return the results in a form of DataSet and it is defined as :

---------------------------------------
//a web method which retrieves data (last names of about given
//thing in form of a data set
[WebMethod(BufferResponse=true)]
public DataSet getLastNames() {
//string var representing sql string
string sql = "";

//create a new temp dataset
DataSet ds = new DataSet();
try {
//open the connection
scConn.Open();

//create the sql
sql = "SELECT LastName FROM tblEmployees";

//create the command
cmd = new SqlCommand(sql,scConn);

//create the sql data adapter
SqlDataAdapter sda = new SqlDataAdapter(cmd);

sda.Fill(ds,"Employees");
Console.WriteLine(ds.Tables.Count);

//clean up code
sda=null;
cmd=null;
scConn.Close();

return ds;
}
catch(Exception ex) { Console.WriteLine(ex.ToString()); }
}
----------------------------------------------------

I want to display the data from the dataset in a DataGrid (in a Windows Form) in a DataGrid. Window form also contains one button which calls webmethod and fills out datagrid. The code is given as :

---------------------------
private void cmdConnect_Click(object sender, System.EventArgs e)
{
try
{
DataSet ds = new DataSet();

localhost.wsEmployees ws = new wsEmployeesClient.localhost.wsEmployees();
ds = ws.getLastNames();

Console.WriteLine(ds.Tables[0].Rows);
}
catch(Exception ex) { Console.WriteLine(ex.ToString()); }
}
------------------------------
note localhost = name of web reference
-----------------------------------

Problem : No records can be found. There is no table in dataset.

I just want to know what i am doing WRONG. Am I missing out something either in code or IIS Server's Administration.

thanx in advance

Re: Datasets and Web Services

Kodanda Pani20-Feb-05 18:24

Kodanda Pani

20-Feb-05 18:24

Hi,

Looks like the code is ok. Try running the webservice alone and see what output you are getting. There may be some problem in accessing the database itself.

Regards
SGS

Timer on a new thread

eggie520-Feb-05 12:15

20-Feb-05 12:15

Uh, i was messing around and came across a problem. I have form with a timer control that runs every 10ms and I wanted it on a new thread. However, I can never get it to work.

Look at this...

public void StartMyThread()
{
    Thread MyThread = new Thread(delegate()
    {
        timer1.Start();
    });
    MyThread.Start();
}

Now, why won't this have my timer run on a new thread?

/\ |_ E X E GG

S. Senthil Kumar20-Feb-05 13:20

S. Senthil Kumar

20-Feb-05 13:20

I don't know why it's not working, is timer1 System.Threading's Timer or System.Timer's Timer?

Why do you want the timer on a separate thread? timer1.Start() is not going to block, you are going to get callbacks/events correctly even if you start the timer without creating a new thread. Any special reasons?

Regards
Senthil
My Blog

eggie520-Feb-05 14:35

20-Feb-05 14:35

I want to put it on a new thread because my "tick" method is being called every 10 ms and the "thing" it does is very processor intensive and results in an un-responsive UI. When I run this code without an extra thread my CPU usgae is 100%.

/\ |_ E X E GG

eggie520-Feb-05 15:08

20-Feb-05 15:08

Take this for example..

private void Form1_Load(object sender, EventArgs e)
{
    Thread MyThread = new Thread(delegate()
    {
        timer1.Start();

    }); MyThread.Start();
}

private void timer1_Tick(object sender, EventArgs e)
{
    this.Text = DateTime.Now.ToLongTimeString();

}

This builds fine. However, the timer1_Tick isn't getting called (at least it isn't putting the time in the title bar). If I take out the threading code and just leave timer1.Start(); it runs fine. How can I get the whole timer opperation onto a new thread?

An interesting note is that I am using the System.Windows.Forms.Timer timer...

/\ |_ E X E GG

S. Senthil Kumar20-Feb-05 15:33

S. Senthil Kumar

20-Feb-05 15:33

There you go, the WindowsForms Timer requires a message loop to be running on the calling thread, that's why it never triggers the Tick event. If you start the timer from the current thread, which happens to be a thread with a message loop (because Form1_Load is called from the main application thread), it works fine. And because it works with the message loop, it can get in the way of other UI messages, that's why your UI might seem unresponsive.

I'd suggest that you use System.Threading.Timer. It doesn't use the message loop.

Anyway, if your timer triggers operations that are CPU intensive, then the usage is going to remain at 100% whether you start the Timer from this thread or a new thread. Your UI might be more responsive though, because the message loop doesn't need to process the Timer messages (which you say are very expensive) every 10ms.

Regards
Senthil
My Blog

eggie520-Feb-05 16:25

Checking the attributes of a directory?

20-Feb-05 16:25

Well, im using the XYgraph component, doing many graphs per second and wanted to put it on a different thread so my UI responds better, which it does.

/\ |_ E X E GG

Marlun20-Feb-05 11:40

Marlun

20-Feb-05 11:40

Hello!

I'm trying to create a windows explorer like treeview and I've got some problems with the "System Volume Information" directory.

Everytime my code tries to work with it the UnauthorizedAccessException is thrown. I was told it is because it's a system folder or something and that I should check the directories attributes and only show the directorys that is not system folders or hidden folders.

How can I check this?

The DirectoryInfo class has the Attributes property but I can't figure out how to use it even though I have tested myDir.Attributes.ToString(); and then I've seen that some directories is hidden and system and so on.

Thanks in advance for any help!

~~~~~~~~~~~~~~
Martin Lundberg
Student, Sweden

I have to thank every member of the Code Project for making it such a great place for a beginner to learn!

How to arrange attribute of PropertyGrid

lee meng20-Feb-05 9:44

lee meng

20-Feb-05 9:44

My propertyGrid looks a bit jumble up...
I have used [CategoryAttribute("abc")] but it is still messy.

How can i arrange my attribute(up or down) to my preperences in the property grid when it is in "categorized" view?

Thank you in advance.

Mathew Hall20-Feb-05 13:47

Mathew Hall

20-Feb-05 13:47

You need to create a TypeConverter for your object and override the GetProperties() method

[TypeConverter(typeof(MyClassConverter))]<br />
public class MyClass <br />
{<br />
  ...<br />
}<br />
<br />
public class MyClassConverter : TypeConverter<br />
{<br />
  public override PropertyDescriptorCollection GetProperties(ITypeDescriptorContext context, object value, Attribute[] attributes)<br />
  {<br />
    // set the order in which the properties appear <br />
    // in the property window<br />
			<br />
    PropertyDescriptorCollection collection = TypeDescriptor.GetProperties(typeof(MyClass), attributes);<br />
<br />
    string[] s = new string[3];<br />
    s[0] = "XYZPropertyName";<br />
    s[1] = "ABCPropertyName";<br />
    s[2] = "IJKPropertyName";<br />
<br />
    return collection.Sort(s);<br />
  }<br />
}

So when you look at the properties of MyClass in the property grid, they appear in the specified order

"I think I speak on behalf of everyone here when I say huh?" - Buffy

lee meng21-Feb-05 6:41

lee meng

21-Feb-05 6:41

I assume MyClass is the propertygrid.SelectedObject class.
Then i do like what u told but the code:

string[] s = new string[3];
s[0] = "XYZPropertyName";
s[1] = "ABCPropertyName";
s[2] = "IJKPropertyName";

i follow exactly cause i don't know what is it?
My program runs the same before and after i added this code.

Please help again, i m very beginner...

Thanks so much for helping.

Mathew Hall21-Feb-05 15:12

Mathew Hall

21-Feb-05 15:12

I assume MyClass is the propertygrid.SelectedObject class.
Yes.

Instead of

public class MyClassConverter : TypeConverter

try replacing it with

public class MyClassConverter : ExpandableObjectConverter

instead

"I think I speak on behalf of everyone here when I say huh?" - Buffy