/// <summary>
/// 设置存储在地图上的注记的字体和大小
/// </summary>
/// <param name="map"></param>
/// <param name="graphicsLayerName"></param>
/// <param name="fontName">注记字体（此值为""、空白字符或null，则不改变注记字体）</param>
/// <param name="size">注记大小（此值小于等于0，则不改变注记大小）</param>
public static void SetAnnotationFontOnMap(this IMap map, string graphicsLayerName, string fontName = null, int size = 0)
{
IGraphicsLayer graphicsLayer = map.GetGraphicsLayer(graphicsLayerName);
IGraphicsContainer graphicContainer = graphicsLayer as IGraphicsContainer;
var txtElements = graphicContainer.GetTextElements();
foreach (var txtElement in txtElements)
{
ITextSymbol txtSymbol = txtElement.Symbol;
//注意不能使用下面这一句，直接设置txtElement.Symbol.Size = size 是无效的，原因未知
//txtElement.Symbol.Size = size;
if (size > 0)
{
txtSymbol.Size = size;
}
if (!string.IsNullOrEmpty(fontName) && fontName.Trim() != string.Empty)
{
System.Drawing.Font font = new System.Drawing.Font(fontName, (float)txtSymbol.Size);
IFontDisp fontDisp = ESRI.ArcGIS.ADF.COMSupport.OLE.GetIFontDispFromFont(font) as IFontDisp;
txtSymbol.Font = fontDisp;
}
txtElement.Symbol = txtSymbol;
graphicContainer.UpdateElement(txtElement as IElement);
}
}