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You're right, Senthil. 
I was trying to print the member's value directly instead of assigning a value, and got an error. I assumed that it was because the variable was not created. 
Cheers,
Vikram.
"When I read in books about a "base class", I figured this was the class that was at the bottom of the inheritence tree. It's the "base", right? Like the base of a pyramid." - Marc Clifton.
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A value type is always allocated whenever it is in scope, that means that it always has a value. If you haven't assigned a value to it, the value is undefined (e.g. unknown or "random").
Most of the time, though, the compiler won't let you use a variable that has an undefined value.
The Point class has an IsEmpty property and an Empty field that you can use to specify an unassigned value:
private Point _wallLocation = Point.Empty;
The _wallLocation.IsEmpty property returns true when the location is undefined.
---
b { font-weight: normal; }
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-Rowan- wrote: What is the best way to allocate a ValueType that has nothing stored in it if I can't null it?
If you're the author of the type, you could have a special static property to do that, something like
struct MyStruct
{
static MyStruct Empty
{
return new MyStruct(<Some Invalid Value>);
}
}
-Rowan- wrote: If I use the first example does that mean that the Point is actually allocated? If so does it have random data in it? This would imply that the two options above cost exactly the same processor wise.
Almost but not quite true. Your first example does result in a stack allocation. The compiler forces you to initialize all fields before using the instance, so you won't run into random data.
The second line of code causes the compiler to emit a .initobj IL instruction, which results in all fields in the struct being initialized to their default values.
Regards
Senthil
_____________________________
My Blog | My Articles | WinMacro
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Hi.
I have a website where i want to pass some values from one site to another.
my problem is that i store the values in an array, but the length must not be longer or shorter than needed.
example:
http://mywebsite.com/graph.aspx?item1=cat&item2=horse&item3=dog
string item1 = Page.Request.Params["item1"].ToString();
string item2 = Page.Request.Params["item2"].ToString();
string[] labels = { item1, item2, item3 };
but if the user inserts "&item4=cow" into the url, then it would give an error.
i need the labels array to extend so that it gets item4 if item4 exsist in the URL.
I new to this, please help me.
-- modified at 5:26 Wednesday 14th December, 2005
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You can't change the size of an array, so you either have to determine how many items you need before you create the array, or use a collection (like ArrayList or Hashtable).
---
b { font-weight: normal; }
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Or......
At startup allocate one receive buffer that will accomodate that largest message you expect (plus a little overhead is OK too). Then on your message received function, New a temp buffer of the exact size of the received message and then Array.Copy the new message into a buf, then use it however you wish.
Mike Luster
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in a Extended column, if the entry is invalid i want to keep focus, but when user presses direction key i lose focus.
2. Problem is, in a datagrid which all columns are extended xolumns, when the user press tab key, cursor moves 2 cells.
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I extend DataGridTextBoxColumn class as DataGridDateTimeExtendedColumn class
I use this class for date entries. When user pushes to 3rd number -for month- i automatically add string a point for separator. Bur whenever adds something to entry , Commit event raised so it doesnt work properly. What can be problem?
All i want is a control which user can input in format "dd.mm.yyyy"
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hi.
I need a sample code to use Add.parameters of command object for SQLClient, please.
Best wishes
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Hello
Ok, Lets imagine we have a Table in sqlServer with these fields:
id (int) , name (nVarChar) , sex (bit)
I show you examples about UPDATE Query with Parameters :
strSQLUpdate = "UPDATE Table SET name=@name,sex=@sex WHERE idu=@idu" ;<br />
cmd = new SqlCommand(strSQLUpdate,Connection) ;<br />
cmd.Parameters.Add ("@id",SqlDbType.Int, 4,"id") ;<br />
cmd.Parameters ["@id"].Value = txtID.Text ;<br />
cmd.Parameters.Add ("@name",SqlDbType.NVarChar, 20,"name") ;<br />
cmd.Parameters ["@name"].Value = txtUsername.Text ;<br />
cmd.Parameters.Add ("@sex",SqlDbType.Bit, 1,"sex") ;<br />
cmd.Parameters ["@sex"].Value = radioButton.Value ;<br />
cmd.ExecuteNonQuery() ;
If you need more codes please alert me and wait 5 hours.
Bye.
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And same sample code using oledb & odbc, please?
Best wishes
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Hi Friends,
I am developing application based on .net Remoting. In my client application i have accessed the remote object by Activator.GetObject function. In this GetObject function, i have passed the second argument as URL, like "tcp://localhost:8384/Container". From my client program how can i validate this URL ? i.e., before using this url i need to identify whether any service is published on this URL or not. Please help me to solve this issue.
Regards,
Prakash.
A Journey of thousand miles must begin with a single step.
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Hi friends,
Am having a grid with a TextBoxColumn which has a combobox...
What eventhandler should be used if ,after selecting the item from the combo,i use the up and down arrow keys to move up and down the rows of the grid.?
Combobox's Leave event is getting fired when i use tab key or mouse alone...
Need urgent help..plz...
Thanx...
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Hi friends,
I tried myself and got the solution....
if anyone needs the solution, ask me.....
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I'm having the source code of the web site with streams,response and request.Then i must find the links in sourcecode.i have got a regex that email finds.
string mail=@"(href=)((')|(""))(mailto (?<mail>(.*))((')|(""))";
So i need another regex that about link.How can i learn the regex writing regulation in C# or how can i write linkregex.
i need have only the website url on this code.
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Hi!
If you want to learn how to use RegEx, just search in google. Helpful is one of the regex trainer which let you test your regex search-string before you use it.
But here is an example to catch URLs:
// Clear old data in listboxes
listBox1.Items.Clear();
listBox2.Items.Clear();
// example HTML document
string lsCode = "<HTML><BODY>test1<BR><A HREF='LinkURL1'>Link1</A><BR>test2<BR>" +
"<A HREF='LinkURL2'>Link2</A><BR></BODY></HTML>";
// Regex object to search
System.Text.RegularExpressions.Regex loCheck = null;
// search-string for regex (improtant: ignorecase-option)
loCheck = new System.Text.RegularExpressions.Regex("href=[\"']{0,1}([^\"'> ]*)", System.Text.RegularExpressions.RegexOptions.IgnoreCase);
System.Text.RegularExpressions.MatchCollection loLinks = loCheck.Matches(lsCode);
// write every value in the list
foreach (System.Text.RegularExpressions.Match loResult in loLinks)
{
// loResult.Groups[0].Value = "HREF='LinkURL1"
// loResult.Groups[1].Value = "LinkURL1"
listBox1.Items.Add(loResult.Groups[1].Value.ToString());
}
// search-string for regex (improtant: ignorecase-option)
loCheck = new System.Text.RegularExpressions.Regex("[\"']>{0,1}>([^<]*)</A>", System.Text.RegularExpressions.RegexOptions.IgnoreCase);
System.Text.RegularExpressions.MatchCollection loLinksText = loCheck.Matches(lsCode);
// write every value in the list
foreach (System.Text.RegularExpressions.Match loResult in loLinksText)
{
// loResult.Groups[0].Value = "'>Link1</A>"
// loResult.Groups[1].Value = "Link1"
listBox2.Items.Add(loResult.Groups[1].Value.ToString());
}
In listBox1, all Link addresses will be added. In listBox2, all link text (within <A HREF>???</A>) will be added.
Marcel Erz
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Hallo C# Friends  ,
I've a problem and hope for help.
I've created an automation addin for excel with .Net 1.1. It works fine.
Now, the same addin should work with fw 2.0.
I created a new Project with vs2005 (Addin Project). Same settings like the old addin.
I installed the addin and want getting started. But the addin won't start. The Function OnConnect never get started.
Has anybody else the same Problem or can anybody give me help?
Thank for attention
Mario
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hi,
I want to design a report (Crystal report) programmatically but I can't find any document to help me . Please help me.
Thanks for your help
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Dear group:
I have this Marco witch I wanna run it from my C# App.
Sub Macro1()<br />
If ActiveWindow.View.SplitSpecial <> wdPaneNone Then<br />
ActiveWindow.Panes(2).Close<br />
End If<br />
If ActiveWindow.ActivePane.View.Type = wdNormalView Or ActiveWindow. _<br />
ActivePane.View.Type = wdOutlineView Then<br />
ActiveWindow.ActivePane.View.Type = wdPrintView<br />
End If<br />
ActiveWindow.ActivePane.View.SeekView = wdSeekCurrentPageHeader<br />
Selection.TypeText Text:="<big>a header here</big>"<br />
ActiveWindow.ActivePane.View.SeekView = wdSeekMainDocumentEnd Sub
This is what I did but got an error in *oWord.
oWord.ActiveWindow.ActivePane.View.SeekView = Word.WdSeekView.wdSeekCurrentPageHeader;<br />
*oWord.Selection.TypeText text = "<big>a header here</big>";<br />
oWord.ActiveWindow.ActivePane.View.SeekView = Word.WdSeekView.wdSeekMainDocument;
My goal is adding a Header with Dynamic Text.
Tnx in advance.
Always ,
Hovik Melkomian.
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i'm trying to use " in a string variable but can't.
So:
string x=""";
how can i do that?
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\ <-- is the escape char
string myString = "Hello \"World\"";
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Escape the quote using the \ escape character:
string x = "\"";
or use a @-quoted string and double quotes:
string x = @"""";
---
b { font-weight: normal; }
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Hi!
In C# you cannot do that in that way, this is just possible in VB. But you can use excape sequences for that:
string x = "\"";
The Backslash shows the compiler: 'the next charcater is a control character and not an normal character!'.
Her are other Escape-sequences:
\n = new line
\r = carriage return
\t = tab stop
Marcel Erz
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Yes, it's possible in C#. @-quoted strings in C# works just like strings in VB:
string x = @"""";
---
b { font-weight: normal; }
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Hi!
Thx! Didn't know!
Marcel Erz
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