从后面的代码访问自定义控件的WPF模板

Question

我试图从代码隐藏的默认模板中访问自定义控件的命名网格.
但是,即使在调用ApplyTemplate()之后,控件的模板似乎也为null.
控件构造器内部是不可能的？
这是代码:

Generic.xaml:
...
<ControlTemplate TargetType="{x:Type local:TimeTableControl}">
    <Grid Name="ContentGrid">
    </Grid>
</ControlTemplate>
...

TimeTableControl.cs:

public TimeTableControl()
{
    ApplyTemplate();
    contentGrid = (Grid)(Template.FindName("ContentGrid", this));  
     //Line above causes null-pointer-exception
     ...
}

Answer 1

您应该将代码移动到重写的OnApplyTemplate并使用GetTemplateChild方法,如下所示:

public class TimeTableControl {

    private Grid contentGrid;

    protected override void OnApplyTemplate() {

        base.OnApplyTemplate();

        contentGrid = GetTemplateChild("ContentGrid") as Grid;

    }

}