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Ain't me babe wrote: there is another way of doing
There are many ways of doing this, you have asked for an opinion on one of the basic precepts of developing applications, how to manage my data. It is unlikely you can get a satisfactory answer via a forum. This takes some years to get a good handle on.
It looks like you are doing all your data manipulation in the UI whereas most people will do it in the database or the object layer. EG I would have created a view in SQL to service the grid, but then I would not have used a grid in the first place, I would use a treeviw and implement drag and drop from listviews of players and comps.
You are also relying on the UI data controls to do your work - this will hurt you will quickly find their limitations (about now). Look into Data Access Layer (DAL), it is a complete change from what you are doing but will serve you in the future.
Good luck
Never underestimate the power of human stupidity
RAH
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Hi All,
Im experimenting with multithreading , now I have a question relating to a sample project that I did.
heres my code...
using System.Threading;
public partial class _Default : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{
Thread threadone = new Thread(new ThreadStart(ProcessOne));
threadone.Start();
Thread threadtwo = new Thread(new ThreadStart(ProcessTwo));
threadtwo.Start();
}
public void ProcessOne()
{
for (int i = 0; i < 10; i++)
{
while (i)
{
}
DropDownList1.Items.Add(i.ToString());
}
return;
}
public void ProcessTwo()
{
for (int i = 10; i < 20; i++)
{
DropDownList2.Items.Add(i.ToString());
}
return;
}
}
Ive got two dropdown lists that I populate with numbers, yet the result is different each time I run the program.
Sometimes one list is populated and the other is isnt and vice versa.
I guess the main question Im asking is how I make it consistently populate both of the lists each team.
Could somebody explain how this would be inappropriate and when is the best times to use multithreading?
Kind Regards
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The best time to use threads is when you have some long task that needs to be done while the user can still play around with the GUI.
I also use it alot with web browser type stuff, web scraping for example. I had an app where I needed to scrap like 5000 web pages for simple data off each, so I multithreaded it to run like 75 at a time, drastically reducing the wait time needed to run.
The best way to accelerate a Macintosh is at 9.8m/sec² - Marcus Dolengo
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Thanks for the advice, so its best to use it when doing big tasks.
As for my code I posted, could you somehow explain why the lists sometimes get populated and sometimes it doesnt?
Kind Regards
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It could be that the thread doesn't get its work done before the form draws itself. That would be my guess.
When working with threads, you need to make sure that each thread only messes with stuff that is on its own thread. Google thread safety and you should find what I am talking about. Fix that and it may work, if not, force the form to redraw itself after you add things to the list.
The best way to accelerate a Macintosh is at 9.8m/sec² - Marcus Dolengo
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I will be sure to have a look at the reference. Thanks again!
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No problem, I haven't used multithreading too extensively either, but some of the stuff you'll be doing as you learn it I should be able to help with, just post here on CP and your sure to get help.
The best way to accelerate a Macintosh is at 9.8m/sec² - Marcus Dolengo
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Hi,
two or more threads will execute their code at their own pace; the exact sequence of things overall cannot be predicted unless you enforce some ordering by synchronizing the threads.
Their independence is their biggest advantage, one thread could be searching a disk while another is crawling the web, all have their own unpredictable delays.
If you must protect a shared data structure against inconsistencies, or if your overall logic requires sequential access for some reason, you need synchronization (with locks, mutexes, whatever).
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So I guess that it is kind of pointless to have multithreads if they all do the same thing, whereas they are more useful if they do different tasks.
Thanks
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Hi,
it may make sense to have a few identical threads that each execute a sequence of various operations, say some calculations, some disk I/O, some networking; even when they start in sync, they will evolve differently and may well end up with one performing calculations, one waiting for the disk, and one waiting for the network; each in turn shifting their roles.
But indeed the more natural situation is where different kinds of things are organized in separate threads: one calculating, one performing disk I/O, one taking care of the network, etc.
BTW: that is what OO principles automatically make you do anyhow; the disk is an object, and you give it some threads if that seems appropriate; the network idem; etc.
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Adding to what others said,
When you use such kind of threads in web applications, thread will be started and if it is doing some long job, ASP.NET will finish rendering the page and send back to client without waiting the thread to finish. So you need to use Thread.Join or wait handles to wait on the worker thread until it finishes. But this makes the usage of threads kinda pointless.
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 The add new method of the Currency Manager fails with my checkbox that is bounded to a data table.
This is how I bound my checkbox to my table.
cbxAvailable.Databindings.Add(“Checked”,invManTable,”IsAvailable”);
This is the Add code that runs when I click the Add button:
myPosition = invManManager.Position;
invManManager.AddNew();
When I run the program I cannot add a new row to my table. How can I fix this?
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I have an MDI form with a menu strip. When I open a child and maximize the child within the mdi parent an icon appears on the left of my menu items. When clicking on this item I get the options to restore, minimize, close, etc...
I have 2 questions regarding this. First, how can I change this icon? I've set the icon for the MDI parent, but the icon appearing here seems to be some type of default visual studio icon. Second, I've used a custom color table to set the menu colors in my form. This menu is not picking up my color table. How can I change these things?
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bcryner wrote: I've set the icon for the MDI parent,
You're putting child-forms into the MDI-parent, right? Don't they have their own .Icon property that defaults to the VS-default if you don't set it?
I are troll
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Good suggestion. However, I just tried it and still no luck 
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Hello,
I am try to edit an xml file via DataSet in my C# app, by adding a new table to the structure with multiple nodes to the structure - but the table should be a child table of one of the existing Tables in the structure I have read in.
In other words:
<parenttable>
<data1>FOO
Should end up like this:
<parenttable>
<data1>FOO
<mychildtable>
<test>BAR
I'm having problems getting the table in the correct place when I write the XML after I change it. I am adding the table/fields/records, and setting up the relations, but for some reason when I process the xml the new table I have added just appends to the end of the xml file and doesnt appear in the branch where it should.
Here is the code snippet of what I'm doing:
XmlTextReader xmlreader1 = new XmlTextReader("Test.xml");
DataSet ds = new DataSet();
ds.ReadXml(xmlreader1);
DataTable newTable = new DataTable();
newTable.TableName = "MyChildTable";
newTable.Columns.Add( "NewField" );
newTable.Columns.Add( "ParentTable_ID",System.Type.GetType("System.Int32") );
ds.Tables.Add( newTable );
ds.Tables["MyChildTable"].ParentRelations.Add( "MyChildTable", ds.Tables["ParentTable"].Columns["ParentTable_ID"], ds.Tables["MyChildTable"].Columns["ParentTable_ID"], true);
DataRow newRow;
newRow = ds.Tables["MyChildTable"].NewRow();
newRow["Test"] = "Value";
newRow["ParentTable_ID"] = "1";
ds.Tables["MyChildTable"].Rows.Add(newRow);
ds.AcceptChanges();
StreamWriter myStreamWriter = new StreamWriter("Out.xml" );
ds.WriteXml(myStreamWriter);
myStreamWriter.Close();
Can anyone see what I am doing incorrectly or have any suggestions?
Thanks,
Greg
greg@ram-software.com
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Hello all,
how to insert a space with patten matching in c#?
I need to find a string "[a-z][0-9]xyz"
and insert a space before "xyz" how can we achieve?
E.g.
"bddd"
should be changed to
"b ddd"
Character at place "b" can be anything but "ddd" will be static.
Can i use regular expression?
Thanks
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Member 2324483 wrote:
Can i use regular expression?
You could take the regex pattern (?<word>\w*)ddd and use the replace pattern ${word} ddd
Regex.Replace(someString, @"(?<word>\w*)ddd", "${word} ddd")
regards
modified 12-Sep-18 21:01pm.
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thanks that perfectly worked. I used it for single non-space character like below:
<code>Regex.Replace(someString, @"(?<word>\S)ddd", "${word} ddd")</code>
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Today i was attempting (for the first time) to make a simple application that will allow me to read XML file into Grid View control (via DataSet), and later on save back any changes back to xml file (Win forms application).
For time being i'm "ignoring" the "save" part, as i'm not able even to get the "view/load" part to work proerply, so i will try to get that working later on once i fix the initial problem i'm seeking help for.
I've tried something thats throwing me exception but since i've never tried binding a dataset to XML i'm probably doing something stupid or missing something...
i've made simple xml file (named it: XMLFile1.xml) with the following content:
<?xml version="1.0" encoding="utf-8" ?>
<item_list>
<item>
<title>item 1</title>
<des>item 1 description</des>
</item>
<item>
<title>item 2</title>
<des>item 2 description</des>
</item>
</item_list>
on the form i added:
1. button with default name of button1.
2. DataGridView with default name of dataGridView1.
3. DataSet with default name of dataSet1.
inside the data grid i've created 2 columns with names "title" & "des".
finally created click event for button with the following:
private void button1_Click(object sender, EventArgs e)
{
string xmlPath = @"..\..\XMLFile1.xml";
dataSet1.ReadXml( xmlPath, XmlReadMode.ReadSchema );
dataGridView1.DataMember = "item";
}
Now the problem i have is the line:
dataGridView1.DataMember = "item";
is thowing exception of "Child list for field item cannot be created".
The truth is i'm not sure if this error is result of invalid xml file i've created, or i'm not using properly the DataMember property.
I would appreciate if anyone could help me & point me in right direction of what i'm doing wrong here.
best regards,
Idan B.
"Assumptions is the mother of all f***ups"
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I just quickly browsed your post, so I may be way off on the answer, but it looks like you are on the right track.
DataSet dsXml = new DataSet();
dsXml.ReadXml(fileName);
Within a DataSet you can have multiple DataTable objects depending on the format of the XML. What I've done in the past is to create a dynamic combo box that gets the name of every single table in the DataSet.
You would want to set the DataSource of you DataGridView to the DataSet object we read (dsXml). Then when your combo box changes you can set the data member to the name of the selected item.
private void LoadComboBox()
{
foreach (DataTable tbl in dsXml.Tables)
{
ComboBox1.Items.Add(tbl.TableName);
}
}
private void SetSource()
{
DataGridView1.DataSource = dsXml;
}
private void OnComboChanged()
{
DataGridView1.DataMember = ComboBox1.Text;
}
You could also set the source to a specific table in the DataSet.
DataGridView1.DataSource = dsXml.Tables[0];
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Thank you very much for your reply.
While i was reading your reply, i came aware of the Tables[] collection and assigning the Tables[0] was half of the solution for my problem.
i had in my code 2 problems:
1. Seems columns werent created properly.
Adding this line:
dataGridView1.AutoGenerateColumns = true;
Solved it. Wierd thing is i had already 2 coulmns with names "title" & "des".
2. As mentioned in begining, nothing was showing up on GridView, till i've pointed DataSource to be Tables[0].
Solution looks like this:
private void button1_Click(object sender, EventArgs e)
{
string xmlPath = @"..\..\XMLFile1.xml";
dataSet1.ReadXml(xmlPath);
dataGridView1.AutoGenerateColumns = true;
dataGridView1.DataSource = dataSet1.Tables[0];
}
EDIT:
I found why the columns i previously added wouldnt show up the values i wanted.
Previously neglected to set on the column the DataPropertyName to "title" & "des" as well.
I wrongly assumed that the "name" of field was enough.
With the DataPropertyName set properly, code looks like:
private void button1_Click(object sender, EventArgs e)
{
string xmlPath = @"..\..\XMLFile1.xml";
dataSet1.ReadXml(xmlPath);
dataGridView1.DataSource = dataSet1.Tables[0];
}
the only problem was need to set source to table 0.
"Assumptions is the mother of all f***ups"
modified on Thursday, December 18, 2008 11:30 AM
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Instead of: dataGridView1.DataMember = "item";
try: dataGridView1.DataMember = "item_list";
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thanks for your reply.
I'm afraid that solution does not work. This also result with "Child list for field item_list cannot be created." exception.
See my reply to the other answer given to me, that helped me find the solution to problem.
Solution involved setting dataSource to first table only (Tables[0]) (and i've also neglected to set DataPropertyName before which was also the problem).
"Assumptions is the mother of all f***ups"
modified on Thursday, December 18, 2008 11:31 AM
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