270 lines
10 KiB
HTML
270 lines
10 KiB
HTML
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
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<html xmlns="http://www.w3.org/1999/xhtml" xmlns:xlink="http://www.w3.org/1999/xlink">
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<head>
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<meta content="text/html; charset=utf-8" http-equiv="Content-Type">
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<title>Item Reordering</title>
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<link href="style.css" rel="stylesheet" type="text/css">
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<link href="prettify.css" type="text/css" rel="stylesheet">
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<script type="text/javascript" src="prettify.js"></script><script type="text/javascript" src="lang-vb.js"></script><link href="../resources/main.css" media="screen" rel="stylesheet" type="text/css">
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</head>
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<body onload="prettyPrint()"><div class="placing">
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<br><table class="navigation"><tr>
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<td class="navigation-previous"><a href="chapter-item-hierarchy.html"><strong>
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« Item Hierarchy</strong></a></td>
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<td class="navigation-index"><a href="../../../quick-start-guide/better-listview/index.html"><strong>Index</strong></a></td>
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<td class="navigation-next"><a href="chapter-items.html"><strong>Items »
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</strong></a></td>
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</tr></table>
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<br><h1>Item Reordering</h1>
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<div class="banner">
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<a href="../../../blog/page/6/index.html"><img src="../resources/overview.gif" alt="Better ListView" class="ss"></a>
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<div class="inside">
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<div class="text">Better ListView: Ultimate .NET ListView replacement control for WinForms (C#, VB.NET)</div>
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<span class="dbtn-c dbtn-hilight"><span class="dbtn-w"><a href="../../../betterlistview.exe" class="dbtn">Download</a></span></span>
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<span class="dbtn-c"><span class="dbtn-w"><a href="../../../blog/page/6/index.html" class="dbtn">More Info</a></span></span>
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</div>
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</div>
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<p class="images"><img src="item-reorder.png"></p>
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<p>Changing item order by dragging items can be turned on by setting
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<span class="code">ItemReorderMode</span> to one of the following values:</p>
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<ul style="list-style:none">
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<li>
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<span class="code">Disabled</span><ul style="list-style:none"><li>
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<p>Item reordering is disabled (default value).</p>
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</li></ul>
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</li>
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<li>
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<span class="code">Enabled</span><ul style="list-style:none"><li>
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<p>Item reordering is enabled and automatic.</p>
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</li></ul>
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</li>
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<li>
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<span class="code">Custom</span><ul style="list-style:none"><li>
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<p>Item reordering is enabled, but the actual reordering is up to
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the user.</p>
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</li></ul>
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</li>
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</ul>
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<p>The reordering is realized through Drag and Drop mechanism.</p>
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<p>Item reordering can supports groups and item hierarchy.</p>
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<p>Target location of reordered items is displayed using <strong><em><a href="chapter-insertion-mark.html">Insertion mark</a></em></strong>. If the
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reordering cannot be performed (e.g. when inserting item between its own
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children), then the insertion mark is displayed as disabled and the
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reordering will not be performed.</p>
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<h2>Reordering Options</h2>
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<p>There are several item reordering options to adjust the feature for
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working with groups and hierarchical items. These options can be used as
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flags of the enumm property <span class="code">ItemReorderOptions</span>:</p>
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<ul style="list-style:none">
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<li>
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<span class="code">AllowCreateChild</span><ul style="list-style:none"><li>
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<p>Allow creating a child items by inserting item into another
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item without children.</p>
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</li></ul>
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</li>
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<li>
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<span class="code">AutoCollapse</span><ul style="list-style:none"><li>
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<p>Collapse item with children prior to reordering.</p>
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</li></ul>
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</li>
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<li>
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<span class="code">KeepGroups</span><ul style="list-style:none"><li>
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<p>Do not change item groups when reordering.</p>
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</li></ul>
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</li>
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<li>
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<span class="code">KeepItemHierarchy</span><ul style="list-style:none"><li>
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<p>Keep parent-child item relations when reordering.</p>
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</li></ul>
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</li>
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<li>
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<span class="code">None</span><ul style="list-style:none"><li>
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<p>No options are active.</p>
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</li></ul>
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</li>
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<li>
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<span class="code">SameParentOnly</span><ul style="list-style:none"><li>
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<p>Allow reordering items with same parent item only.</p>
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</li></ul>
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</li>
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</ul>
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<p>None of the extra options are on by default so the default value is
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<span class="code">ItemReorderOptions.None</span>.</p>
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<h2>Auto-Expansion Checking</h2>
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<p>Auto expansion checking is performed during item reordering and
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looks whether it is valid to auto expand item over which mouse cursor
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hovers. By default, there is only one situation when auto expansion is not
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allowed: Item which is auto-collapsed will not be than auto-expanded
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again.</p>
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<p>It is possible to add custom checking (e.g. when some items or
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groups should not expand when user drags items over it) by handling
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<span class="code">CheckAutoExpand</span> event and than set
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<span class="code">BetterListViewCheckAutoExpandEventArgs.IsValid</span> to
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<span class="code">false</span> whenever you want to deny auto-expansion. Event data
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contains both source and target items.</p>
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<h2>Item Reordering Checking</h2>
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<p>Checking for item reorder validity is performed during item
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reordering. It looks for possible reasons why the reordering may not be
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valid (e.g. reordering parent item into itself) and sets
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<span class="code">BetterListViewItemReorderEventArgs.InvalidationReasons</span>
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property. The property can have the following flags:</p>
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<ul style="list-style:none">
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<li>None<ul style="list-style:none"><li>
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<p>Item reorder is valid.</p>
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</li></ul>
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</li>
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<li>NotTopLevel<ul style="list-style:none"><li>
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<p>Item reorder is invalid in case of data binding when other
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than top-level item is being reordered.</p>
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</li></ul>
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</li>
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<li>NotSameParent<ul style="list-style:none"><li>
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<p>Item is being reordered under different parent when
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SameParentOnly item reordering option is turned on.</p>
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</li></ul>
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</li>
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<li>PutInItself<ul style="list-style:none"><li>
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<p>Item is being reordered under itself.</p>
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</li></ul>
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</li>
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<li>AnotherGroup<ul style="list-style:none"><li>
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<p>Item is being reordered in differenet group while changing
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groups is not allowed.</p>
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</li></ul>
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</li>
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<li>Custom<ul style="list-style:none"><li>
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<p>User-specified reason for invalid item reorder.</p>
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</li></ul>
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</li>
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</ul>
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<p>You can override the <span class="code">OnCheckItemReorder</span> method or add
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<span class="code">CheckItemReorder</span> event handler to add your own
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validation.</p>
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<p>Event data contains read-only property called <span class="code">IsValid</span>,
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which is true whenever <span class="code">InvalidationReasons</span> property is equal
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to <span class="code">BetterListViewInvalidationReasons.None</span>.</p>
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<p>Item reorder validity influences appearance of insertion mark (will
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be displayed in disabled state) and whether the reordering will be
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performed.</p>
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<h2>Item Reordering Info</h2>
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<p>When user releases mouse button, the <span class="code">ItemReorder</span> event
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is raised. You can find useful properties in the event data:</p>
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<ul style="list-style:none">
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<li>Locations<ul style="list-style:none"><li>
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<p>Item locations before and after reordering structured as
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key-value pairs within dictionary.</p>
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</li></ul>
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</li>
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<li>SourceItems<ul style="list-style:none"><li>
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<p>Items being reordered.</p>
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</li></ul>
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</li>
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<li>TargetAddress<ul style="list-style:none"><li>
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<p>Target item address before reordering.</p>
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</li></ul>
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</li>
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<li>TargetAddressAdjusted<ul style="list-style:none"><li>
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<p>Target item address after reordering. When doing custom
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reordering, this <strong><em>adjusted</em></strong> address is relevant
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when source items are removed from the list.</p>
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</li></ul>
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</li>
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</ul>
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<h2>Sample Source Code</h2>
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<p><strong>C#</strong></p>
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<pre class="prettyprint"><code class="lang-cs">this.listView.BeginUpdate();
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this.listView.Columns.Add("column");
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this.listView.Items.AddRange(
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new[]
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{
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"first item",
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"second item",
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"third item",
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"fourth item",
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"fifth item"
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});
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// enable item reordering
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this.listView.ItemReorderMode = BetterListViewItemReorderMode.Enabled;
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this.listView.EndUpdate();</code></pre>
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<p><strong>Visual Basic</strong></p>
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<pre class="prettyprint"><code class="lang-vb">ListView.BeginUpdate()
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ListView.Columns.Add ("column")
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ListView.Items.AddRange (
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New String() { _
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"first item",
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"second item",
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"third item",
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"fourth item",
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"fifth item"
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})
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' enable item reordering
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ListView.ItemReorderMode = BetterListViewItemReorderMode.Enabled
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ListView.EndUpdate()</code></pre>
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<br><div class="banner">
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<a href="../../../blog/page/6/index.html"><img src="../resources/overview.gif" alt="Better ListView" class="ss"></a>
|
||
<div class="inside">
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||
<div class="text">Better ListView: Ultimate .NET ListView replacement control for WinForms (C#, VB.NET)</div>
|
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<span class="dbtn-c dbtn-hilight"><span class="dbtn-w"><a href="../../../betterlistview.exe" class="dbtn">Download</a></span></span>
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||
<span class="dbtn-c"><span class="dbtn-w"><a href="../../../blog/page/6/index.html" class="dbtn">More Info</a></span></span>
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||
</div>
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||
</div>
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<table class="navigation"><tr>
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||
<td class="navigation-previous"><a href="chapter-item-hierarchy.html"><strong>
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« Item Hierarchy</strong></a></td>
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<td class="navigation-index"><a href="../../../quick-start-guide/better-listview/index.html"><strong>Index</strong></a></td>
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<td class="navigation-next"><a href="chapter-items.html"><strong>Items »
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</strong></a></td>
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</tr></table>
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<br><table class="footer"><tr>
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<td class="footer-title">Better ListView Documentation
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</td>
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<td class="footer-copyright">
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Copyright © 2010-2012 <a href="../../../index.html" target="_blank">ComponentOwl.com</a>
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</td>
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</tr></table>
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</div></body>
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</html>
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