Question

I want to create an app that has a listbox on the left side (I’ll style it to make it look good later).

On the right side, I want to have an area where I can add controls, etc

So the question is what do I need to do to split the Window into two unequal parts
(left side approx 350 pixels wide and height should be the entire window) and the remainder is for my “canvas.”

Answer 1

You can use a Grid:

<Grid>
    <Grid.ColumnDefinitions>
        <ColumnDefinition Width="350" /> <!-- Or Auto -->
        <ColumnDefinition Width="*" />
    </Grid.ColumnDefinitions>
    <ListBox Grid.Column="0" />
    <Canvas Grid.Column="1" />
</Grid>

Or you could use a DockPanel:

<DockPanel>
    <ListBox DockPanel.Dock="Left" Width="350" />
    <Canvas />
</DockPanel>

The benefit of the Grid is you have finer control over the layout and could allow the end user to dynamically resize the columns using a GridSplitter.