How to draw an line-arrow?(如何画直线箭头) NPOI-V2.6.1

[SummerCSharp]

How to use HSSFClientAnchor、HSSFSimpleShape draw an line-arrow?
（画一个直线上带一个箭头）
Like the screenshot below：

Divider-------------------------------------------------------------------------------------------------------

HSSFClientAnchor c1 = new HSSFClientAnchor(dx1, dy1, dx2, dy2, start_x, start_y, end_x, end_y);
HSSFSimpleShape shape = patriarch.CreateSimpleShape(c1);
shape.ShapeType = HSSFSimpleShape.OBJECT_TYPE_LINE;
shape.LineStyle = HSSFShape.LINESTYLE_SOLID;
//在NPOI中线的宽度12700表示1pt,所以这里是0.5pt粗的线条。
shape.LineWidth = _lineWidth;
shape.SetLineStyleColor(110, 10, 110);

Modify one of the enumeration values(shape.ShapeType 、shape.LineStyle) ?

是修改shape.ShapeType 、shape.LineStyle其中的某个值吗

[SummerCSharp]

I have found a solution.

void AddArrow(HSSFSimpleShape shape)
{
Type type = shape.GetType();
MethodInfo methodInfo = type.GetMethod("SetPropertyValue", BindingFlags.Instance | BindingFlags.NonPublic);
if (methodInfo != null)
{
var escherSimpleProperty2 = new EscherSimpleProperty(EscherProperties.LINESTYLE__LINESTARTARROWHEAD, false, false, 0x01);
methodInfo.Invoke(shape, new object[] { escherSimpleProperty2 });
}
}

void AddArrowOverTurn(HSSFSimpleShape shape)
{
Type type = shape.GetType();
MethodInfo methodInfo = type.GetMethod("SetPropertyValue", BindingFlags.Instance | BindingFlags.NonPublic);
if (methodInfo != null)
{
var escherSimpleProperty2 = new EscherSimpleProperty(EscherProperties.LINESTYLE__LINEENDARROWHEAD, false, false, 0x01);
methodInfo.Invoke(shape, new object[] { escherSimpleProperty2 });
}
}