Have I gone completely mad? [modified]
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Wait... don't answer that. So at work I'm doing up a quick and dirty ASP.NET application that uses a
TreeView. I'm still a bit of a beginner to programming for the web so I've been through the installed MSDN docs quite a bit for the past couple of weeks but I just ran across something that utterly blew my mind. Anybody who has worked withTreeViewknows it's got a few quirks, namely dealing with the fact that it's biased towards hierarchical data (why else would you use it?). I haven't had a lot of experience using .NET collections for a lot of things so combine that fact with the fun hierarchical nature ofTreeViewnodes and I have a lot of help doc reading to catch up on. So I'm trying to find some sort of way to get at aTreeNodeCollectionindex without having to loop through anIEnumeratorlike so:'enumerate through the nodes on this level and find out what the currently selected
'node's index is
Dim nodeEnumerator As IEnumerator
If selectedNode.Parent Is Nothing Then
nodeEnumerator = trvTasks.Nodes.GetEnumerator
Else
nodeEnumerator = selectedNode.Parent.ChildNodes.GetEnumerator
End If'Counter code goes here
I'm hitting random members and I happen to land on the
RemoveAtpage. No big deal, right? There's no good information here on finding an index or anything... Whiskey. Tango. Foxtrot. :omg: From the integrated VS2005 help:C++
void button2_Click( Object^ /*sender*/, EventArgs^ /*e*/ )
{
// Delete the first TreeNode in the collection
// if the Text property is S"Node0."
if ( this->treeView1->Nodes[ 0 ]->Text->Equals( "Node0" ) )
{
this->treeView1->Nodes->RemoveAt( 0 );
}
}Now I've dabbled in C++, and I've even done a little MFC in school, but is this really what you have to do in Managed C++? If C# is supposed to be all the best things about C++ then this looks like all the worst... No wonder nobody wants to touch the stuff.
Why are you using an IEnumerator variable in your VB sample? Can't you use a NodeCollection variable and do a foreach loop instead?
This blanket smells like ham
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Well, when I was learning C++, ^ meant to the power of, /* */ meant some sort of comment, and -> meant accessing something through a pointer. From that stance, the method signature above contains an Object and an EventArgs to the power of... something, as well as two parameters that are essentially comments. Also, the first executable line tells me that you're going through the this pointer to hit the treeView1 pointer, which hits the Nodes pointer, which dereferences to the Text property, which somehow is also a pointer and must be dereferenced to hit the Equals method. Am I missing something or shouldn't there be a dot or two in there somewhere? As for the index, I need to know where my selected node is so I can insert nodes before and after it.
TreeNodeCollectiondoes give me anAddAtmethod that takes an integer index parameter... but the collection doesn't give me any way to access a node's index.Robert Royall wrote:
when I was learning C++, ^ meant to the power of
in C++ ^ is the XOR operator, not power of operator... though i have no idea what its supposed to be doing there in the function you posted :|
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Well, when I was learning C++, ^ meant to the power of, /* */ meant some sort of comment, and -> meant accessing something through a pointer. From that stance, the method signature above contains an Object and an EventArgs to the power of... something, as well as two parameters that are essentially comments. Also, the first executable line tells me that you're going through the this pointer to hit the treeView1 pointer, which hits the Nodes pointer, which dereferences to the Text property, which somehow is also a pointer and must be dereferenced to hit the Equals method. Am I missing something or shouldn't there be a dot or two in there somewhere? As for the index, I need to know where my selected node is so I can insert nodes before and after it.
TreeNodeCollectiondoes give me anAddAtmethod that takes an integer index parameter... but the collection doesn't give me any way to access a node's index.May I ask you where you learned c++, since to my recollection the ^ symbol was never user as power of but was and is used as an BIT wise Exclusive OR. In Managed C++ however the ^ is also used as pointer to managed objects 'newed' with gcnew instead of new.
codito ergo sum
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May I ask you where you learned c++, since to my recollection the ^ symbol was never user as power of but was and is used as an BIT wise Exclusive OR. In Managed C++ however the ^ is also used as pointer to managed objects 'newed' with gcnew instead of new.
codito ergo sum
Wow, I had completely forgotten that from my one year varsity of C++ back in '96. I still don;t remember the power operator.
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Wow, I had completely forgotten that from my one year varsity of C++ back in '96. I still don;t remember the power operator.
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May I ask you where you learned c++, since to my recollection the ^ symbol was never user as power of but was and is used as an BIT wise Exclusive OR. In Managed C++ however the ^ is also used as pointer to managed objects 'newed' with gcnew instead of new.
codito ergo sum
Sorry, you are correct, ^ is XOR in C++. I got it mixed up with my VB syntax, which uses ^ as the power operator.
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Why are you using an IEnumerator variable in your VB sample? Can't you use a NodeCollection variable and do a foreach loop instead?
This blanket smells like ham
I could have used foreach instead, but I wanted my code to reflect the fact that I was enumerating the collection only to count it. I tend to think of using foreach as "I'm doing something to each of these items in the collection", so I thought I'd use IEnumerator to specifically call out to myself that I'm only walking the collection and not making any edits.
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I could have used foreach instead, but I wanted my code to reflect the fact that I was enumerating the collection only to count it. I tend to think of using foreach as "I'm doing something to each of these items in the collection", so I thought I'd use IEnumerator to specifically call out to myself that I'm only walking the collection and not making any edits.
Interesting, I've never made that distinction before. I've had to avoid using foreach when I was modifying the collection (adding and removing elements), but for everything else I just use foreach. Personally I find the IEnumerator interface rather ugly and suspect it was designed to be hidden under the covers, so I'm content to leave it there. I definitely respect any conventions that make code easier to follow and understand though.
This blanket smells like ham
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Interesting, I've never made that distinction before. I've had to avoid using foreach when I was modifying the collection (adding and removing elements), but for everything else I just use foreach. Personally I find the IEnumerator interface rather ugly and suspect it was designed to be hidden under the covers, so I'm content to leave it there. I definitely respect any conventions that make code easier to follow and understand though.
This blanket smells like ham
It is eerily reminiscent of COM, isn't it? Just when you thought you were free from interface coclasses... :~ Actually, thinking on some of the comments in this topic, I ended up going back and rewriting it as a
forloop this morning anyway, which let me keep the same counter variable and get rid of the IEnumerator. -
It is eerily reminiscent of COM, isn't it? Just when you thought you were free from interface coclasses... :~ Actually, thinking on some of the comments in this topic, I ended up going back and rewriting it as a
forloop this morning anyway, which let me keep the same counter variable and get rid of the IEnumerator.At one point in my life IDL actually started to make sense to me. X| :wtf:
This blanket smells like ham
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At one point in my life IDL actually started to make sense to me. X| :wtf:
This blanket smells like ham
I'm very sorry and I hope you can find the help you need. :doh:
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Wait... don't answer that. So at work I'm doing up a quick and dirty ASP.NET application that uses a
TreeView. I'm still a bit of a beginner to programming for the web so I've been through the installed MSDN docs quite a bit for the past couple of weeks but I just ran across something that utterly blew my mind. Anybody who has worked withTreeViewknows it's got a few quirks, namely dealing with the fact that it's biased towards hierarchical data (why else would you use it?). I haven't had a lot of experience using .NET collections for a lot of things so combine that fact with the fun hierarchical nature ofTreeViewnodes and I have a lot of help doc reading to catch up on. So I'm trying to find some sort of way to get at aTreeNodeCollectionindex without having to loop through anIEnumeratorlike so:'enumerate through the nodes on this level and find out what the currently selected
'node's index is
Dim nodeEnumerator As IEnumerator
If selectedNode.Parent Is Nothing Then
nodeEnumerator = trvTasks.Nodes.GetEnumerator
Else
nodeEnumerator = selectedNode.Parent.ChildNodes.GetEnumerator
End If'Counter code goes here
I'm hitting random members and I happen to land on the
RemoveAtpage. No big deal, right? There's no good information here on finding an index or anything... Whiskey. Tango. Foxtrot. :omg: From the integrated VS2005 help:C++
void button2_Click( Object^ /*sender*/, EventArgs^ /*e*/ )
{
// Delete the first TreeNode in the collection
// if the Text property is S"Node0."
if ( this->treeView1->Nodes[ 0 ]->Text->Equals( "Node0" ) )
{
this->treeView1->Nodes->RemoveAt( 0 );
}
}Now I've dabbled in C++, and I've even done a little MFC in school, but is this really what you have to do in Managed C++? If C# is supposed to be all the best things about C++ then this looks like all the worst... No wonder nobody wants to touch the stuff.
Were you just trying to delete the treeview thingy you clicked on via index? try this: Private Sub TreeView1_MouseUp(ByVal sender As Object, ByVal e As System.Windows.Forms.MouseEventArgs) Handles TreeView1.MouseUp me.TreeView1.Controls.RemoveAt( me.TreeView1.Controls.GetChildIndex(me.TreeView1.GetChildAtPoint(new Drawing.Point(e.x,e.Y))) End Sub
GaltSalt maker of .Net thingys
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Were you just trying to delete the treeview thingy you clicked on via index? try this: Private Sub TreeView1_MouseUp(ByVal sender As Object, ByVal e As System.Windows.Forms.MouseEventArgs) Handles TreeView1.MouseUp me.TreeView1.Controls.RemoveAt( me.TreeView1.Controls.GetChildIndex(me.TreeView1.GetChildAtPoint(new Drawing.Point(e.x,e.Y))) End Sub
GaltSalt maker of .Net thingys
No, actually I was just trying to access a node's index in the TreeNodeCollection in order to be able to insert another node before or after it in the collection. I just noticed the somewhat incomprehensible code in the Managed C++ section of the MSDN help for that method while I was browsing around.
Please don't bother me... I'm hacking code right now. Doesn't anybody remember what "hacking" really means? :sigh: