Below is the summary from the MonoMac API.  My suggestions appear as comments.  In my opinion XxxCount was clearest in most cases.  I did not propose changes to the members of any of the [Model] classes, or NSBrowserDelegate, as I am not sure of the implications or what reads best.  <meta charset="utf-8">Make (or reject) any changes you want and I will implement.  <br>
<br><font class="Apple-style-span" face="&#39;courier new&#39;, monospace"><div>=========</div><div>Appkit.cs</div><div>=========</div><div><span class="Apple-tab-span" style="white-space:pre">        </span>interface NSBitmapImageRep {</div>
<div><span class="Apple-tab-span" style="white-space:pre">                </span>[Export (&quot;numberOfPlanes&quot;)]</div><div><span class="Apple-tab-span" style="white-space:pre">                </span>int Planes { get; }</div><div><span class="Apple-tab-span" style="white-space:pre">                </span>// use PlaneCount</div>
<div>--</div><div><span class="Apple-tab-span" style="white-space:pre">        </span>interface NSBrowser {</div><div><span class="Apple-tab-span" style="white-space:pre">                </span>[Export (&quot;numberOfVisibleColumns&quot;)]</div>
<div><span class="Apple-tab-span" style="white-space:pre">                </span>int VisibleColumns { get; }</div><div><span class="Apple-tab-span" style="white-space:pre">                </span>// use VisibleColumnCount</div><div>--</div><div><span class="Apple-tab-span" style="white-space:pre">        </span>interface NSBrowserDelegate {</div>
<div><span class="Apple-tab-span" style="white-space:pre">                </span>[Export (&quot;browser:numberOfRowsInColumn:&quot;), EventArgs (&quot;NSBrowserColumn&quot;)]</div><div><span class="Apple-tab-span" style="white-space:pre">                </span>int RowsInColumn (NSBrowser sender, int column);</div>
<div><span class="Apple-tab-span" style="white-space:pre">                </span></div><div><span class="Apple-tab-span" style="white-space:pre">                </span>[Export (&quot;browser:numberOfChildrenOfItem:&quot;)]</div><div><span class="Apple-tab-span" style="white-space:pre">                </span>int CountChildren (NSBrowser browser, NSObject item);</div>
<div>--</div><div><span class="Apple-tab-span" style="white-space:pre">        </span>interface NSColor {</div><div><span class="Apple-tab-span" style="white-space:pre">                </span>[Export (&quot;numberOfComponents&quot;)]</div><div>
<span class="Apple-tab-span" style="white-space:pre">                </span>int ComponentCount { get; }</div><div>--</div><div><span class="Apple-tab-span" style="white-space:pre">        </span>interface NSColorSpace {</div><div><span class="Apple-tab-span" style="white-space:pre">                </span>[Export (&quot;numberOfColorComponents&quot;)]</div>
<div><span class="Apple-tab-span" style="white-space:pre">                </span>int ColorComponents { get; }</div><div><span class="Apple-tab-span" style="white-space:pre">                </span>// use ComponentCount</div><div>--</div><div><span class="Apple-tab-span" style="white-space:pre">        </span>interface NSComboBox {</div>
<div><span class="Apple-tab-span" style="white-space:pre">                </span>[Export (&quot;numberOfVisibleItems&quot;)]</div><div><span class="Apple-tab-span" style="white-space:pre">                </span>int VisibleItems { get; set; }</div><div>
<span class="Apple-tab-span" style="white-space:pre">                </span>// use VisibleItemCount</div><div><br></div><div><span class="Apple-tab-span" style="white-space:pre">                </span>[Export (&quot;numberOfItems&quot;)]</div><div><span class="Apple-tab-span" style="white-space:pre">                </span>int Count { get; }</div>
<div><span class="Apple-tab-span" style="white-space:pre">                </span>// use ItemCount</div><div>--</div><div><span class="Apple-tab-span" style="white-space:pre">        </span>[Model]</div><div><span class="Apple-tab-span" style="white-space:pre">        </span>interface NSComboBoxDataSource {</div>
<div><span class="Apple-tab-span" style="white-space:pre">                </span>[Export (&quot;numberOfItemsInComboBox:&quot;)]</div><div><span class="Apple-tab-span" style="white-space:pre">                </span>int ItemCount (NSComboBox comboBox);</div>
<div>--</div><div><span class="Apple-tab-span" style="white-space:pre">        </span>interface NSFont {</div><div><span class="Apple-tab-span" style="white-space:pre">                </span>[Export (&quot;numberOfGlyphs&quot;)]</div><div><span class="Apple-tab-span" style="white-space:pre">                </span>int GlyphCount { get; }</div>
<div>--</div><div><span class="Apple-tab-span" style="white-space:pre">        </span>interface NSGradient {</div><div><span class="Apple-tab-span" style="white-space:pre">                </span>[Export (&quot;numberOfColorStops&quot;)]</div>
<div><span class="Apple-tab-span" style="white-space:pre">                </span>int ColorStopsCount { get; }</div><div><span class="Apple-tab-span" style="white-space:pre">                </span>// use ColorStopCount</div><div>--</div><div><span class="Apple-tab-span" style="white-space:pre">        </span>interface NSMenu {</div>
<div><span class="Apple-tab-span" style="white-space:pre">                </span>[Export (&quot;numberOfItems&quot;)]</div><div><span class="Apple-tab-span" style="white-space:pre">                </span>int Count { get; }</div><div>--</div><div><span class="Apple-tab-span" style="white-space:pre">        </span>[Model]</div>
<div><span class="Apple-tab-span" style="white-space:pre">        </span>interface NSMenuDelegate {</div><div><span class="Apple-tab-span" style="white-space:pre">                </span>[Export (&quot;numberOfItemsInMenu:&quot;)]</div><div><span class="Apple-tab-span" style="white-space:pre">                </span>int MenuItemCount (NSMenu menu);</div>
<div>--</div><div><span class="Apple-tab-span" style="white-space:pre">        </span>interface NSOpenGLPixelFormat {</div><div><span class="Apple-tab-span" style="white-space:pre">                </span>[Export (&quot;numberOfVirtualScreens&quot;)]</div>
<div><span class="Apple-tab-span" style="white-space:pre">                </span>int NumberOfVirtualScreens { get; }</div><div><span class="Apple-tab-span" style="white-space:pre">                </span>//use VirtualScreenCount</div><div>--</div><div>
<span class="Apple-tab-span" style="white-space:pre">        </span>[Model]</div><div><span class="Apple-tab-span" style="white-space:pre">        </span>interface NSOutlineViewDataSource {</div><div><span class="Apple-tab-span" style="white-space:pre">                </span>[Export (&quot;outlineView:numberOfChildrenOfItem:&quot;)]</div>
<div><span class="Apple-tab-span" style="white-space:pre">                </span>int GetChildrenCount (NSOutlineView outlineView, NSObject item);</div><div>--</div><div><span class="Apple-tab-span" style="white-space:pre">        </span>interface NSMatrix {</div>
<div><span class="Apple-tab-span" style="white-space:pre">                </span>[Export (&quot;numberOfRows&quot;)]</div><div><span class="Apple-tab-span" style="white-space:pre">                </span>int Rows { get; }</div><div><span class="Apple-tab-span" style="white-space:pre">                </span>// use RowCount</div>
<div><br></div><div><span class="Apple-tab-span" style="white-space:pre">                </span>[Export (&quot;numberOfColumns&quot;)]</div><div><span class="Apple-tab-span" style="white-space:pre">                </span>int Columns { get; }</div><div>
<span class="Apple-tab-span" style="white-space:pre">                </span>// use ColumnCount</div><div>--</div><div><span class="Apple-tab-span" style="white-space:pre">        </span>interface NSLevelIndicator {</div><div><span class="Apple-tab-span" style="white-space:pre">                </span>[Export (&quot;numberOfTickMarks&quot;)]</div>
<div><span class="Apple-tab-span" style="white-space:pre">                </span>int TickMarkCount { get; set; }</div><div><br></div><div><span class="Apple-tab-span" style="white-space:pre">                </span>[Export (&quot;numberOfMajorTickMarks&quot;)]</div>
<div><span class="Apple-tab-span" style="white-space:pre">                </span>int MajorTickMarkCount { get; set; }</div><div>--</div><div><span class="Apple-tab-span" style="white-space:pre">        </span>interface NSLevelIndicatorCell {</div>
<div><span class="Apple-tab-span" style="white-space:pre">                </span>[Export (&quot;numberOfTickMarks&quot;)]</div><div><span class="Apple-tab-span" style="white-space:pre">                </span>int TickMarkCount { get; set; }</div><div>
<br></div><div><span class="Apple-tab-span" style="white-space:pre">                </span>[Export (&quot;numberOfMajorTickMarks&quot;)]</div><div><span class="Apple-tab-span" style="white-space:pre">                </span>int MajorTickMarkCount { get; set; }</div>
<div>--</div><div><span class="Apple-tab-span" style="white-space:pre">        </span>interface NSPopUpButton {</div><div><span class="Apple-tab-span" style="white-space:pre">                </span>[Export (&quot;numberOfItems&quot;)]</div><div>
<span class="Apple-tab-span" style="white-space:pre">                </span>int ItemCount { get; }</div><div>--</div><div><span class="Apple-tab-span" style="white-space:pre">        </span>interface NSPopUpButtonCell {</div><div><span class="Apple-tab-span" style="white-space:pre">                </span>[Export (&quot;numberOfItems&quot;)]</div>
<div><span class="Apple-tab-span" style="white-space:pre">                </span>int Count { get; }</div><div><span class="Apple-tab-span" style="white-space:pre">                </span>// use ItemCount</div><div>--</div><div><span class="Apple-tab-span" style="white-space:pre">        </span>interface NSSlider {</div>
<div><span class="Apple-tab-span" style="white-space:pre">                </span>[Export (&quot;numberOfTickMarks&quot;)]</div><div><span class="Apple-tab-span" style="white-space:pre">                </span>int TickMarksCount { get; set; }</div><div>
<span class="Apple-tab-span" style="white-space:pre">                </span>// use TickMarkCount</div><div>--</div><div><span class="Apple-tab-span" style="white-space:pre">        </span>interface NSSliderCell {</div><div><span class="Apple-tab-span" style="white-space:pre">                </span>[Export (&quot;numberOfTickMarks&quot;)]</div>
<div><span class="Apple-tab-span" style="white-space:pre">                </span>int TickMarks { get; set; }</div><div><span class="Apple-tab-span" style="white-space:pre">                </span>// use TickMarkCount</div><div>--</div><div><span class="Apple-tab-span" style="white-space:pre">        </span>interface NSTableView {</div>
<div><span class="Apple-tab-span" style="white-space:pre">                </span>[Export (&quot;numberOfColumns&quot;)]</div><div><span class="Apple-tab-span" style="white-space:pre">                </span>int ColumnCount { get; }</div><div><br></div>
<div><span class="Apple-tab-span" style="white-space:pre">                </span>[Export (&quot;numberOfRows&quot;)]</div><div><span class="Apple-tab-span" style="white-space:pre">                </span>int RowCount { get; }</div><div>--</div><div><span class="Apple-tab-span" style="white-space:pre">                </span>[Export (&quot;numberOfSelectedColumns&quot;)]</div>
<div><span class="Apple-tab-span" style="white-space:pre">                </span>int SelectedColumnsCount { get; }</div><div><span class="Apple-tab-span" style="white-space:pre">                </span>// use SelectedColumnCount</div><div>--</div><div>
<span class="Apple-tab-span" style="white-space:pre">                </span>[Export (&quot;numberOfSelectedRows&quot;)]</div><div><span class="Apple-tab-span" style="white-space:pre">                </span>int SelectedRowCount { get; }</div><div>--</div>
<div><span class="Apple-tab-span" style="white-space:pre">        </span>[Model]</div><div><span class="Apple-tab-span" style="white-space:pre">        </span>interface NSTableViewDataSource {</div><div><span class="Apple-tab-span" style="white-space:pre">                </span>[Export (&quot;numberOfRowsInTableView:&quot;)]</div>
<div><span class="Apple-tab-span" style="white-space:pre">                </span>int GetRowCount (NSTableView tableView);</div><div>--</div><div><span class="Apple-tab-span" style="white-space:pre">        </span>[Model]</div><div><span class="Apple-tab-span" style="white-space:pre">        </span>interface NSTableViewSource {</div>
<div><span class="Apple-tab-span" style="white-space:pre">                </span>[Export (&quot;numberOfRowsInTableView:&quot;)]</div><div><span class="Apple-tab-span" style="white-space:pre">                </span>int GetRowCount (NSTableView tableView);</div>
<div>--</div><div><span class="Apple-tab-span" style="white-space:pre">        </span>interface NSTabView {</div><div><span class="Apple-tab-span" style="white-space:pre">                </span>[Export (&quot;numberOfTabViewItems&quot;)]</div>
<div><span class="Apple-tab-span" style="white-space:pre">                </span>int Count { get; }</div><div><span class="Apple-tab-span" style="white-space:pre">                </span>// use TabViewItemCount </div><div>--</div><div><span class="Apple-tab-span" style="white-space:pre">        </span>interface NSTextTable {</div>
<div><span class="Apple-tab-span" style="white-space:pre">                </span>[Export (&quot;numberOfColumns&quot;)]</div><div><span class="Apple-tab-span" style="white-space:pre">                </span>int Columns { get; set; }</div><div><span class="Apple-tab-span" style="white-space:pre">                </span>// use ColumnCount</div>
<div>--</div><div><span class="Apple-tab-span" style="white-space:pre">        </span>interface NSRuleEditor {</div><div>        <span class="Apple-tab-span" style="white-space: pre; ">        </span>[Export (&quot;numberOfRows&quot;)]</div>
<div>        <span class="Apple-tab-span" style="white-space: pre; ">        </span>int NumberOfRows { get; }</div><div><span class="Apple-tab-span" style="white-space:pre">                </span>// use RowCount</div><div>--</div><div><span class="Apple-tab-span" style="white-space:pre">        </span>[Model]</div>
<div>  <span class="Apple-tab-span" style="white-space:pre">        </span>interface NSRuleEditorDelegate {</div><div>        <span class="Apple-tab-span" style="white-space: pre; ">        </span>[Export (&quot;ruleEditor:numberOfChildrenForCriterion:withRowType:&quot;), DelegateName (&quot;NSRuleEditorNumberOfChildren&quot;), DefaultValue(0)]</div>
<div>        <span class="Apple-tab-span" style="white-space: pre; ">        </span>int NumberOfChildren (NSRuleEditor editor, NSObject criterion, NSRuleEditorRowType rowType);</div><div><br></div><div>============</div><div>coreimage.cs</div>
<div>============</div><div>    <span class="Apple-tab-span" style="white-space:pre">interface CIColor {
        </span>[Export (&quot;numberOfComponents&quot;)]</div><div><span class="Apple-tab-span" style="white-space:pre">        </span>int NumberOfComponents { get; }</div><div><span class="Apple-tab-span" style="white-space:pre">        </span>//use ComponentCount</div>
<div><span class="Apple-tab-span" style="white-space:pre">        </span></div><div>==================</div><div>nslayoutmanager.cs</div><div>==================</div><div>    <span class="Apple-tab-span" style="white-space:pre">interface NSLayoutManager {
        </span>[Export (&quot;numberOfGlyphs&quot;)]</div><div><span class="Apple-tab-span" style="white-space:pre">        </span>int NumberOfGlyphs { get; }</div><div><span class="Apple-tab-span" style="white-space:pre">        </span>//use GlyphCount</div>
<div><span class="Apple-tab-span" style="white-space:pre">        </span></div><div>============</div><div>src/qtkit.cs</div><div>============</div><div><div>    interface QTSampleBuffer {</div></div><div><span class="Apple-tab-span" style="white-space:pre">        </span>[Export (&quot;numberOfSamples&quot;)]</div>
<div><span class="Apple-tab-span" style="white-space:pre">        </span>int SampleCount { get; }</div><div><br></div></font>