wpf - XAML - The property 'Content' is set more than once -

wpf - XAML - The property 'Content' is set more than once -

very new wpf , xaml. can't head around why can't place wpf command in next code. issue <canvas></canvas> tags are. set in place gives me 'the property 'content' set more once'

if explain in simple terms content property set helpful.

i have checked out next articles no avail: the property 'content' set more once the property content set more once property content set more once the property 'content' set more 1 time button wpf controltemplate causeing error "the property 'content' set more once"

<window x:class="pdfindexer.mainwindow" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" title="mainwindow" height="350" width="525"> <grid x:name="parentgrid"> <grid.rowdefinitions> <rowdefinition height="auto" /> <rowdefinition height="1*" /> <rowdefinition height="25" /> </grid.rowdefinitions> <menu grid.row="0" > <menuitem header="file" > <menuitem header="open project" click="menuitem_click_1"></menuitem> <menuitem header="save project"></menuitem> <menuitem header="close project"></menuitem> <separator></separator> <menuitem header="exit"></menuitem> </menuitem> <menuitem header="edit"></menuitem> </menu> <tabcontrol grid.row="1"> <tabitem header="document flow" > outline of entire document placed. <canvas></canvas> </tabitem> <tabitem header="preview"> preview drawn screen. </tabitem> <tabitem header="resources"> resources { graphic files, fonts, info files } </tabitem> <tabitem header="code library"> user can save re-usable bits of code. useful when adding intel barcodes or address blocks etc... </tabitem> </tabcontrol> <statusbar grid.row="2"> items </statusbar> </grid>

by adding text description tabitem added content when added canvas added additional item of content not allowed tabitem. need utilize command can hold collection of children such canvas, grid, stackpanel etc. seek this.

<tabcontrol grid.row="1"> <tabitem header="document flow"> <canvas> <textblock> outline of entire document placed. </textblock> </canvas> </tabitem> <tabitem header="preview"> preview drawn screen. </tabitem> <tabitem header="resources"> resources { graphic files, fonts, info files } </tabitem> <tabitem header="code library"> user can save re-usable bits of code. useful when adding intel barcodes or address blocks etc... </tabitem> </tabcontrol>

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