Xamarin Grid的RowSpan/ColSpan无法拉伸问题求助

Hey there! Let’s work through that frustrating height-stretching issue with your rotated custom view in the 5×5 Grid. Rotated elements can throw layout systems for a loop, so here are some targeted fixes to get your view filling the full height of the first column:

• Fix the rotated view's size reporting
  When you rotate a view 90 degrees, its width and height effectively swap—but the layout system doesn’t automatically account for this. Override the OnMeasure method in your custom view to swap the width/height constraints and return the corrected size. This tells the parent Grid exactly how much space the rotated view needs:

protected override SizeRequest OnMeasure(double widthConstraint, double heightConstraint)
{
    // Swap constraints since we're rotated 90°
    var measuredSize = base.OnMeasure(heightConstraint, widthConstraint);
    // Return swapped dimensions so the layout system uses the correct bounds
    return new SizeRequest(
        new Size(measuredSize.Request.Height, measuredSize.Request.Width),
        new Size(measuredSize.Minimum.Height, measuredSize.Minimum.Width)
    );
}

• Ensure your Grid's row definitions are set to expand
  If the rows in your 5×5 Grid are set to Auto, they’ll only take up the space needed by the Entry controls in the first column. Instead, set all row heights to * so they distribute the available height evenly, which gives your custom view (spanning all 5 rows) a consistent full-height container:

<Grid.RowDefinitions>
    <RowDefinition Height="*" />
    <RowDefinition Height="*" />
    <RowDefinition Height="*" />
    <RowDefinition Height="*" />
    <RowDefinition Height="*" />
</Grid.RowDefinitions>

• Clear fixed size requests and set proper layout options
  Fixed WidthRequest/HeightRequest values can override the layout system’s ability to stretch your view. Remove those first, then set these properties on your custom view:

  • VerticalOptions="FillAndExpand"
  • HorizontalOptions="FillAndExpand"
  • Grid.RowSpan="5" (to span all 5 rows)
  • Make sure the second column’s definition is <ColumnDefinition Width="*" /> so it takes up remaining space in the Grid.

• Double-check your custom view's internal Grid
  The two side-by-side charts inside your custom view might be limiting its height too. Make sure that internal Grid has:

  • VerticalOptions="FillAndExpand"
  • Row definitions set to * (if applicable) so the charts fill the full height of the custom view.

• Verify your rotation implementation
  If you’re using the Rotation property, ensure you’re setting AnchorX="0.5" and AnchorY="0.5" to rotate around the center—this prevents the view from shifting outside the Grid cell’s bounds. For some frameworks, using a LayoutTransform instead of the Rotation property can yield more reliable layout behavior for rotated elements.

Try these steps one by one—start with overriding OnMeasure, as that’s the most common culprit for rotated view layout issues. You should see your custom view stretch to match the first column’s height once the layout system correctly understands its rotated dimensions.

内容的提问来源于stack exchange，提问作者Catimus