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Can you define what an element means in this case.
“That which can be asserted without evidence, can be dismissed without evidence.”
― Christopher Hitchens
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Probably not. 
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Excellent, I'm delighted that you have the chance to display your abilities in developing an application. Now is your opportunity to prove that you were really listening in your lessons, and that you have the ability to go off and do some research and abstract thinking on your own.
Fortunately for you, the question provides several clues as to what you need to be looking at. The first thing is that you need a generic method. Now, this could mean a couple of things so I'll go over them both with you. The first thing it could mean is that it is a method that has a generic parameter, while the second thing is that it might accept a generic type as an input. I know that seems complicated but it makes more sense when you look at the next requirement that it will accept a list of elements.
Right, your method accepts a generic list. We still haven't decided whether it's a generic parameter or a generic type, but you have some clues that you need a generic list. I suggest you look up List<T> to get an understanding of what I'm talking about (now, you could be really clever and allow the method to accept any type that implements IList<T> but I think you should limit yourself to the basics for the moment). So, you have a List of type T - this is a generic. Now, you could either create your method using something like void MyMethod<TList, TType>(TList items) or void MyMethod<T>(List<T> items). It's up to you, but you need to decide now whether or not you need to apply generic constraints to T. At this point, you really need to decide what elements actually means - does it mean you limit to classes, or do you allow primitive types as well.
The iteration part is trivial - you really should be able to accomplish that on your own.
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You're like a breath of fresh air in this place +5
Everyone dies - but not everyone lives
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This doesn't require generics at all.
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I got the treeview displaying my xml right,
now I just need to get the listview working.
here is the code for the treeview
private void button1_Click(object sender, EventArgs e)
{
try
{
XmlDocument xDoc = new XmlDocument();
xDoc.Load(path + @"\Graw Mission Script\mission.xml");
xDoc.SelectSingleNode("mission_script");
treeView1.Nodes.Clear();
treeView1.Nodes.Add(new TreeNode(xDoc.DocumentElement.Name));
TreeNode tNode = new TreeNode();
tNode = treeView1.Nodes[0];
AddNode(xDoc.DocumentElement, tNode);
treeView1.CollapseAll();
}
catch (XmlException xmlEx) { MessageBox.Show(xmlEx.Message); }
catch (Exception ex) { MessageBox.Show(ex.Message); }
}
private void AddNode(XmlNode inXmlNode, TreeNode inTreeNode)
{
XmlNode xNode;
TreeNode tNode;
XmlNodeList nodeList;
int i;
if (inXmlNode.HasChildNodes)
{
nodeList = inXmlNode.ChildNodes;
for (i = 0; i <= nodeList.Count - 1; i++)
{
xNode = inXmlNode.ChildNodes[i];
inTreeNode.Nodes.Add(new TreeNode(xNode.Name));
tNode = inTreeNode.Nodes[i];
AddNode(xNode, tNode);
}
}
else
{
listView1.Items.Add(inXmlNode.OuterXml);
}
}
I really need help populating to listview
modified 28-Feb-14 17:38pm.
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Massive code-dumps are not the right way to get help here.
What is not working right now: is loading the TreeView not working; or, is it creating some TreeNodes, but what's created is not what you want ?
Where do any specific errors occur, and what are the error messages ?
You say you want to click on a TreeNode, and have it somehow show up in the ListView: but, I see no evidence you've defined an 'AfterSelect EventHandler for the TreeView that would update the ListView.
“The best hope is that one of these days the Ground will get disgusted enough just to walk away ~ leaving people with nothing more to stand ON than what they have so bloody well stood FOR up to now.” Kenneth Patchen, Poet
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daddy356 wrote: help populating to listview
If your goal is to populate the ListView with items linked to only TreeNodes that have no child nodes, then your code looks fine to me. Is there something wrong with the ListView's contents after the tree is constructed ?
How about your goal of synchronizing the ListView with the TreeView ? "click on a node in treeview and display and edit data in listview" can be interpreted a variety of ways, and I'm trying to imagine how that fits in with the state of the ListView after the TreeView is constructed, as shown in your code.
One technique I've used a lot in synchronizing TreeViews and ListViews is to create "symmetric" Dictionaries, like this:
private readonly Dictionary<ListViewItem, TreeNode> dctLvItmToTNode = new Dictionary<ListViewItem, TreeNode>();
private readonly Dictionary<TreeNode, ListViewItem> dctTNodeToLvItm = new Dictionary<TreeNode, ListViewItem>();
private TreeNode currentNode;
private ListViewItem currentLVItem;
private bool dontRecurse;
private void treeView1_AfterSelect(object sender, TreeViewEventArgs e)
{
if (dontRecurse) return;
if (dctTNodeToLvItm.TryGetValue(e.Node, out currentLVItem))
{
dontRecurse = true;
currentLVItem.Selected = true;
dontRecurse = false;
}
}
private void listView1_SelectedIndexChanged(object sender, EventArgs e)
{
if (dontRecurse || listView1.SelectedItems.Count == 0) return;
if (dctLvItmToTNode.TryGetValue(listView1.SelectedItems[0], out currentNode))
{
dontRecurse = true;
treeView1.SelectedNode = currentNode;
dontRecurse = false;
}
}Use of Dictionaries provide fast look-up. Hope this is useful.
“The best hope is that one of these days the Ground will get disgusted enough just to walk away ~ leaving people with nothing more to stand ON than what they have so bloody well stood FOR up to now.” Kenneth Patchen, Poet
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Very strange: I just composed a reply to another post from the OP, "daddy356," dated March 3, which had revised code and some questions, and then got a "no permission" error to post that reply, and now, the post I replied to has disappeared !
Well, in case it might be useful: here it is:
Your first code example showed the ListView only being populated with 'inXmlNode items that had no child nodes.
The second code example shows the ListView being populated when the current selected TreeNode is not a root node (Parent == null), and where the selected node has more than 1 child node, in which case, you want to populate the ListView with all first-level child nodes of the SelectedNode.
I wonder if you didn't mean to test for:
tv.SelectedNode.Nodes.Count > 0 If that's the case then you could exclude the nodes you don't want to represent in the ListView by:
if (tv.SelectedNode.Parent == null || tv.SelectedNode.GetNodeCount(false) == 0) return; Note that the 'false argument to GetNodeCount means it will return the same number as if you executed: SelectedNode.Nodes.Count.
Your code is adding Columns to the ListView, not Items ! Try:
foreach (TreeNode tvNode in tv.SelectedNode.Nodes)
{
listView1.Items.Add(tvNode.Text);
}The secret to using the 'symmetric dictionaries trick I described above relies on making sure that each Node and ListViewItem have "matching" cross-references in the two Dictionaries. In the case that you re-populate the ListView, for cross-selection to work you must re-use the existing ListViewItems, not create new ones.
To make that work, you need to do something like this:
foreach (TreeNode tvNode in tv.SelectedNode.Nodes)
{
listView1.Items.Add(dctTNodeToLvItm[tvNode]);
}
“The best hope is that one of these days the Ground will get disgusted enough just to walk away ~ leaving people with nothing more to stand ON than what they have so bloody well stood FOR up to now.” Kenneth Patchen, Poet
modified 8-Mar-14 10:14am.
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I tried your code, I just don't think I'm including it right in my code.
I managed to get the node text listed in columns and their values
listed below each node.
Now I need to figure out how to edit the value in list view and then save them, also apply an image list to the tree view with
different images for nodes.
Here is what I have:
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.IO;
using System.Linq;
using System.Text;
using System.Windows.Forms;
using System.Xml;
namespace TestXml
{
public partial class test : Form
{
public test()
{
InitializeComponent();
}
private string path = Environment.GetFolderPath(Environment.SpecialFolder.ApplicationData);
XmlDocument xDoc = new XmlDocument();
List<string> values = new List<string>();
private void test_Load(object sender, EventArgs e)
{
textBox1.Text = path + @"\Graw Mission Script\mission.xml";
}
private void button1_Click(object sender, EventArgs e)
{
xDoc.Load(textBox1.Text);
StreamReader sr = new StreamReader(path + @"\Graw Mission Script\mission.xml");
textBox2.Text = sr.ReadToEnd();
try
{
treeView1.Nodes.Clear();
treeView1.Nodes.Add(xDoc.DocumentElement.Name);
AddNode(xDoc.DocumentElement, treeView1.Nodes[0]);
treeView1.CollapseAll();
}
catch (Exception ex) { MessageBox.Show(ex.Message); }
}
public void AddNode(XmlNode inXmlNode, TreeNode inTreeNode)
{
XmlAttributeCollection atts = inXmlNode.Attributes;
TreeNode tNode = new TreeNode("Attributes");
if (atts.Count != 0)
{
foreach (XmlAttribute att in atts)
{
tNode.Nodes.Add(att.Name).Nodes.Add(att.Value);
}
inTreeNode.Nodes.Add(tNode);
}
foreach (XmlNode xNode in inXmlNode.ChildNodes)
{
switch (xNode.NodeType)
{
case XmlNodeType.Element:
tNode = new TreeNode("<" + xNode.Name + ">");
AddNode(xNode, tNode);
break;
case XmlNodeType.Comment:
tNode = new TreeNode("<!--" + xNode.Value + "-->");
break;
case XmlNodeType.CDATA:
tNode = new TreeNode("#cdata " + xNode.Value);
break;
default:
throw new Exception("Unexpected NodeType: " + xNode.NodeType.ToString());
}
inTreeNode.Nodes.Add(tNode);
}
}
private void treeView1_AfterSelect(object sender, TreeViewEventArgs e)
{
listView1.Clear();
TreeView tv = (TreeView)sender;
if (tv.SelectedNode.Text != "Attributes")
{
return;
}
if (tv.SelectedNode.Parent == null || tv.SelectedNode.GetNodeCount(false) == 0) return;
{
foreach (TreeNode tvNode in tv.SelectedNode.Nodes)
{
listView1.Columns.Add(tvNode.Text);
values.Add(tvNode.Nodes[0].Text);
}
ListViewItem item = listView1.Items.Add(values[0]);
values.RemoveAt(0);
if (values.Count > 0)
{
item.SubItems.AddRange(values.ToArray());
}
}
}
private void listView1_SelectedIndexChanged(object sender, EventArgs e)
{
}
}
}
any help with that would be greatly appreciated.
modified 9-Mar-14 18:16pm.
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I will take a look at your current code later today (GMT + 07 here). cheers, Bill
“The best hope is that one of these days the Ground will get disgusted enough just to walk away ~ leaving people with nothing more to stand ON than what they have so bloody well stood FOR up to now.” Kenneth Patchen, Poet
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I really appreciate it cheers
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If you go with the "symmetric dictionary" strategy I suggested, then synchronized updating of edits of the Labels of TreeView Nodes, or ListView Items is easy:
private void treeView1_AfterLabelEdit(object sender, NodeLabelEditEventArgs e)
{
currentNode = e.Node;
if (dctTNodeToLvItm.TryGetValue(currentNode, out currentLVItem))
{
currentLVItem.Text = e.Label;
}
}
private void listView1_AfterLabelEdit(object sender, LabelEditEventArgs e)
{
currentLVItem = listView1.Items[e.Item];
if (dctLvItmToTNode.TryGetValue(currentLVItem, out currentNode))
{
currentNode.Text = e.Label;
}
}More later today, as I have time.
“The best hope is that one of these days the Ground will get disgusted enough just to walk away ~ leaving people with nothing more to stand ON than what they have so bloody well stood FOR up to now.” Kenneth Patchen, Poet
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I'm not really clear on exactly what your intended structure for the TreeView and ListView contents, and interaction are; the reason you create ListView Columns from some TreeNodes escapes me.
And, it is clear that I'd have to really know the details of your data, and the Application structure, to really give you useful feedback. However, I don't have time to really "get my head" into the deep structure of your Application.
I think the most helpful thing I can do is to send you a zipped .NET 4.0 sample (source code) Application that demonstrates TreeView and ListView synchronization via "symmetric" Dictionaries, demonstrates Node and ListViewItem synchronized text/label editing, etc. : [^]. The file has had the executables ripped out to make it smaller: you will need to re-compile. Let me know if you have any problem opening/using the sample Application.
It's always helped me to have working code to study, and then to learn by altering the code.
Hope it's helpful !
I will continue to monitor this thread to see if more specific questions come up.
“The best hope is that one of these days the Ground will get disgusted enough just to walk away ~ leaving people with nothing more to stand ON than what they have so bloody well stood FOR up to now.” Kenneth Patchen, Poet
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Bill,
I just don't know how to apply the code to my code
I tried, so I must be doing something wrong.
and Obviously no one here knows how to do it.
cause if they did I would have an answer.
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<pre lang="xml">I have Two Subscribers 1.SubA 2.SubB I have a table. Table name : Names
I have City column(nvarchar) in my Names table and it is unique key.
User 'A' connects to SubA. user 'B' connects to SubB.
A inserts a row with 'ABC' in to Names table @ 10:30 am.
It will take 20 min to update the publisher. 'B' inserts a row with 'ABC' in to Names table @10:35 am.
I have the unique constraint on the table so.User A's input is updated in the publisher @10:50.
But user B's input caught in the conflicts.
I want the city column should be unique across all the subs.
How could i handle this?How should i display proper message for user B?How should i do validation across all the subscribers</pre></pre>
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I would create a table that stores locks and then lock each row as a user accesses it, so if User A creates a row and is still using that you leave the lock on until User A commits that record. When User B tries to access a row or create a row you check if that row is locked before allowing User B to do anything.
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Probably the safest way to do this is to:
A: catch the exception thrown by the database and bubble it up to the user (in a friendly way)
or
B: add a where clause to your insert (insert into ... where cityname <> '[cityname]'). Retrieve the updated number of rows of your insert query. If it is 0, tell the user the insert was not successfull.
Putting a lock on things poses many new problems.
hope this helps.
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Wow that is really ugly, you have 2 subscriber databases where users enter data and it takes 20 minutes for that information to propagate to the publisher and you want the unique constraint validation on publisher.
I know nothing about distributed database design but this seems completely wrong. I would think the data entry should target the publisher and the subscriber should then take the results.
How do you proposed to get over the 20 minute time lag, forward quantum computing has not been invented yet.
Never underestimate the power of human stupidity
RAH
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@MycroftHolmes,I am new to this distributed database design.When they told me this I was shocked as well.Can anybody please suggest any documents on winform applications with replicated data base.
thanks
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private void AddProducts()
{
int i = 1;
foreach (TabPage tp in tabControl1.TabPages)
{
ObjectQuery<tblProducts> filteredProduct=new ObjectQuery<tblProducts>("Select value p from tblProducts as p where p.ProductType="+i,afos);
FlowLayoutPanel flp = new FlowLayoutPanel();
flp.Dock = DockStyle.Fill;
foreach(tblProducts tprod in filteredProduct)
{
Button b = new Button();
b.Size = new Size(100, 100);
b.Image = tprod.ProductImage;
b.Text=tprod.ProductName;
b.Tag = tprod;
b.Click += new EventHandler(UpdateProductList);
flp.Controls.Add(b);
}
tp.Controls.Add(flp);
i++;
}
}
Please help. I want to automatically call an image from the database and make it an image in the button..I have managed to have the Button automatically add depending on the number of Products on the database, there's no solid button. My only problem is to have the button's image set automatically from the images in the database.
Thank you so much.
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And what is the result of the code that you show?
It's not clear what problem you are having.
The difficult we do right away...
...the impossible takes slightly longer.
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I am using the following code to convert from one type of object to another. It works fine, but I am looking for a way to improve performance:
public static object ConvertObject(object source, Type targetType)
{
object result;
Type sourceType = source.GetType();
DataContractSerializer sourceSerializer = new DataContractSerializer(sourceType);
using (MemoryStream ms = new MemoryStream())
{
DateTime start = DateTime.Now;
sourceSerializer.WriteObject(ms, source);
TimeSpan writeObjectTime = DateTime.Now - start;
ms.Seek(0, SeekOrigin.Begin);
DataContractSerializer targetSerializer = new DataContractSerializer(targetType);
XmlReader r = XmlReader.Create(ms);
DynamicObjectSerializer.MyReader myreader = new DynamicObjectSerializer.MyReader(r);
start = DateTime.Now;
result = targetSerializer.ReadObject(myreader);
TimeSpan readObjectTime = DateTime.Now - start;
LoggerHolder.LogDebug("\"{0}\" Write Time = {1}, Read Time = {2}", source.GetType().Name, writeObjectTime, readObjectTime);
}
return result;
}
Using the MemoryStream actually slows the process down since the object is first being written to it and then read from it. If it was possible to serialize the source object to the target one directly it would have been taken half the time. Any idea how this can be done?
Thanks.
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