[WPF]怎么在样式里定义Grid的行列

Question

<Style x:Key="g" TargetType="Grid">
            <Setter Property="RowDefinitions">
                <Setter.Value>
                    <RowDefinition Height="*"/>
                    <RowDefinition Height="*"/>
                </Setter.Value>
            </Setter>
        </Style>提示RowDefinitions没有set访问器我本来想表达的是:
Grid.RowDefinitions.Add(..)看来IDE理解成:
Grid.RowDefinitions= new ....;怎么写呢?