protected void MeasureAndArrange() { XYChart xyChart = null; object el = FindName("xyChart"); if (el is XYChart) { xyChart = el as XYChart; Size size = new Size(xyChart.Width, xyChart.Height); // Measure and arrange the surface // VERY IMPORTANT xyChart.Measure(size); xyChart.Arrange(new Rect(size)); } }