Delphi ArcEngine 根据条件添加文本注记 _arcengine如何在mapcontrol中添加文字注记-优快云博客

本文介绍了一个 DelphiArcEngine 中实现的函数，该函数可以在地图上根据指定条件为特定图层添加文本注记。函数允许设置注记的字段、颜色、条件表达式及文字大小。

摘要生成于 C知道，由 DeepSeek-R1 满血版支持，前往体验 >

来自： http://www.cnblogs.com/chinacodegear/archive/2009/04/03/1428866.html

function Annotation4Layer(aeMapControl: TMapControl; pLayer: ILayer; sField: string; pColor: IRgbColor;

sWhere: string = ''; iTextSize: SmallInt = 9): Boolean;

//带条件的文字标注，指定图层，字段，颜色和条件表达式，文字大小

var
pFeatureLayer: IFeatureLayer;
pFeatureCursor: IFeatureCursor;
pFeature: IFeature;
pFields: IFields;
pEnvelope: IEnvelope;
pPoint: IPoint;

pTextSymbol: ITextSymbol;
pTextElement: ITextElement;
pElement: IElement;

pActiveView: IActiveView;
pGraphicsContainer: IGraphicsContainer;
pQueryFilter: IQueryFilter;
i: Integer;
begin
pFeatureLayer := pLayer as IFeatureLayer;

if sWhere = '' then
begin
    pFeatureCursor := pFeatureLayer.Search(nil, True);
end
else
begin
    pQueryFilter := CoQueryFilter.Create as IQueryFilter;
    pQueryFilter.WhereClause := sWhere;
    try
      pFeatureCursor := pFeatureLayer.Search(pQueryFilter, True);
    except
      on E: Exception do
      begin
        ShowMessage('查询表达式错误!');
        Exit(False);
      end;
    end;
end;

pFeature := pFeatureCursor.NextFeature;

if pFeature = nil then //空图层时退出
    Exit(False);

pFields := pFeature.Fields;
i := pFields.FindField(sField);

if i < 0 then //字段错误退出
    Exit(False);

pActiveView := aeMapControl.ActiveView;
pGraphicsContainer := aeMapControl.Map as IGraphicsContainer;

//文本符号
pTextSymbol := CoTextSymbol.Create as ITextSymbol;
pTextSymbol.Size := iTextSize;
pTextSymbol.Color := pColor;

pPoint := CoPoint.Create as IPoint;
while pFeature <> nil do
begin
    //文本元素
    pTextElement := CoTextElement.Create as ITextElement;
    pTextElement.ScaleText := True;
    pTextElement.Symbol := pTextSymbol;
    pTextElement.Text := VarToStr(pFeature.Value[i]);

    pEnvelope := pFeature.Extent;
    pPoint.PutCoords(pEnvelope.XMin + pEnvelope.Width / 2, pEnvelope.YMin + pEnvelope.Height / 2);

    pElement := pTextElement as IElement;
    pElement.Geometry := pPoint;

    pGraphicsContainer.AddElement(pElement, 0);
    pFeature := pFeatureCursor.NextFeature;
end;
pActiveView.PartialRefresh(esriViewGraphics, nil, nil);
Result := True;
end;