How can I adjust the textstyle of text object?

[tommy.yang]

I want to draw a text string in my dwg file, but the style of text always remains left alignment, how can I adjust it ?
DBText text = new DBText();
text.TextString = label;
text.Rotation = angle;
text.Position = insPt;
text.Color = Autodesk.AutoCAD.Colors.Color.FromColor(System.Drawing.Color.Plum);
text.Height = DwgUtil.Property.LabelHeight;

This may be a simple question, but I can find the correct way from object browser, please help me, thank you in advance.