第九讲 图层文本标注
上一讲中,我们实现了图层属性表的浏览功能,这一讲给大家讲解图层标注的实现方法。
本文实现的最终效果如下:
图层标注实现起来并不复杂,本例仅做一个简单示范,只加载AE的样式库,标注选定的字段,旨在抛砖引玉。更高级的功能,如自定义样式和修改样式,由读者自己实现。
主要思路:
加载图层字段 –> 加载文本样式 -> 设置文本样式
实现过程:
创建标注设置窗体 -> 创建图层标注的Command -> 添加Command到图层右键菜单
9.1创建标注设置窗体
(1)添加一个Windows窗体,命名为LabelLayerFrm.cs。添加控件如下:
(2)为LabelLayerFrm类添加两个成员变量:
public ILayer pLayer;
private IStyleGalleryItem pStyleGalleryItem;
(3)重载一个构造函数:
public LabelLayerFrm(ILayer layer)
{
InitializeComponent();
pLayer = layer;
}
(4) 添加成员函数ReadRegistry,用于从注册表中读取ArcGIS的安装路径。
///
/// 读取注册表中的制定软件的路径
///
///
///
private string ReadRegistry(string sKey)
{
//Open the subkey for reading
Microsoft.Win32.RegistryKey rk = Microsoft.Win32.Registry.LocalMachine.OpenSubKey(sKey, true);
if (rk == null) return "";
// Get the data from a specified item in the key.
return (string)rk.GetValue("InstallDir");
}
(5)添加LabelLayerFrm窗体的Load事件,以加载图层字段到下拉模型,加载文本样式到SymbologyControl控件。
private void LabelLayerFrm_Load(object sender, EventArgs e)
{
//加载图层字段
ITable pTable = pLayer as ITable;
IField pField = null;
for (int i = 0; i < pTable.Fields.FieldCount; i++)
{
pField = pTable.Fields.get_Field(i);
cbbField.Items.Add(pField.AliasName);
}
cbbField.SelectedIndex = 0;
//获得ArcGIS的安装路径
string sInstall = ReadRegistry("SOFTWARE\\ESRI\\CoreRuntime");
//加载ESRI.ServerStyle 样式文件到SymbologyControl
this.axSymbologyControl1.LoadStyleFile(sInstall + "\\Styles\\ESRI.ServerStyle");
this.axSymbologyControl1.GetStyleClass(esriSymbologyStyleClass.esriStyleClassTextSymbols).SelectItem(0);
}
(6)添加axSymbologyControl1控件的OnItemSelected事件,以设置选定的样式。
private void axSymbologyControl1_OnItemSelected(object sender, ISymbologyControlEvents_OnItemSelectedEvent e)
{
pStyleGalleryItem = (IStyleGalleryItem)e.styleGalleryItem;
}
(7)添加确定按扭的Click事件,为选定图层中的选定的字段以选定的样式标注。
private void btnOK_Click(object sender, EventArgs e)
{
IGeoFeatureLayer pGeoFeatureLayer = pLayer as IGeoFeatureLayer;
pGeoFeatureLayer.AnnotationProperties.Clear();//必须执行,因为里面有一个默认的
IBasicOverposterLayerProperties pBasic = new BasicOverposterLayerPropertiesClass();
ILabelEngineLayerProperties pLableEngine = new LabelEngineLayerPropertiesClass();
ITextSymbol pTextSymbol = new TextSymbolClass();
pTextSymbol = (ITextSymbol)pStyleGalleryItem.Item;
//你可以在这里修改样式的颜色和字体等属性,本文从略
//pTextSymbol.Color
//pTextSymbol.Font
string pLable = "[" + (string)cbbField .SelectedItem + "]";
pLableEngine.expression_r = pLable;
pLableEngine.Isexpression_rSimple = true;
pBasic.NumLabelsOption = esriBasicNumLabelsOption.esriOneLabelPerShape;
pLableEngine.BasicOverposterLayerProperties = pBasic;
pLableEngine.Symbol = pTextSymbol;
pGeoFeatureLayer.AnnotationProperties.Add(pLableEngine as IAnnotateLayerProperties);
pGeoFeatureLayer.DisplayAnnotation = true;
}
至此,标注设置窗体已经完成,如果你编译通不过,看看是不是忘了添加相关引用了。
9.2创建图层标注的Command
(1)创建一个新类,以ArcGIS的BaseCommand为模板,命名为LabelLayerCmd.cs。
注意:在新建Base Command模板时,会弹出一个对话框让我们选择模板适用对象,这时我们要选择MapControl、PageLayoutControl,即选择第二项或者倒数第二项。
(2)添加LabelLayerCmd类的成员变量。
private ILayer pLayer = null;
IMapControl3 pMap;
(3)修改默认构造函数如下:
public LabelLayerCmd(ILayer lyr,IMapControl3 map)
{
//
// TODO: Define values for the public properties
//
base.m_category = ""; //localizable text
base.m_caption = "标注"; //localizable text
base.m_message = "标注"; //localizable text
base.m_toolTip = "标注"; //localizable text
base.m_name = "标注"; //unique id, non-localizable (e.g. "MyCategory_MyCommand")
pLayer = lyr;
pMap = map;
try
{
//
// TODO: change bitmap name if necessary
//
string bitmapResourceName = GetType().Name + ".bmp";
base.m_bitmap = new Bitmap(GetType(), bitmapResourceName);
}
catch (Exception ex)
{
System.Diagnostics.Trace.WriteLine(ex.Message, "Invalid Bitmap");
}
}
(4)修改OnClick函数为:
///
/// Occurs when this command is clicked
///
public override void OnClick()
{
// TODO: Add LabelLayerCmd.OnClick implementation
LabelLayerFrm labelLyrFrm = new LabelLayerFrm(pLayer);
labelLyrFrm.ShowDialog();
pMap.Refresh(esriViewDrawPhase.esriViewGraphics, null, null);
}
9.3添加Command到图层右键菜单
回到3sdnMap主窗体类,找到axTOCControl1_OnMouseDown事件响应函数,修改如下代码片断:
//弹出右键菜单
if (item == esriTOCControlItem.esriTOCControlItemMap)
m_menuMap.PopupMenu(e.x, e.y, m_tocControl.hWnd);
if (item == esriTOCControlItem.esriTOCControlItemLayer)
{
m_menuLayer.AddItem(new OpenAttributeTable(layer), -1, 2, true , esriCommandStyles.esriCommandStyleTextOnly);
//动态添加图层标注的Command到图层右键菜单
m_menuLayer.AddItem(new LabelLayerCmd(layer, m_mapControl), -1, 3, false, esriCommandStyles.esriCommandStyleTextOnly);
//弹出图层右键菜单
m_menuLayer.PopupMenu(e.x, e.y, m_tocControl.hWnd);
//移除菜单项
m_menuLayer.Remove(3);
m_menuLayer.Remove(2);
}
至此,已经完成图层文本标注,编译运行吧,是不是看到开篇的效果了?
以上代码在Windows XP Sp3 + VS2005 + AE9.2/9.3环境下编译通过。